Weather Communications Codes
            A Breathless Overview by Hugh Stegman NV6H

Sources are many, but mostly:
World Meteorological Organization http://www.wmo.ch/
National Oceanic and Atmospheric Agency
http://www.nws.noaa.gov/

0. Why Weather Reporting Codes?
===============================

   In a word, clarity.

   Weather observation codes are very similar from one country to 
another, facilitating the exchange of information despite the 
Babel of languages, measurement units, and time zones.  
Meteorological groups meet regularly to deal with these issues.  
The resulting codes are appropriate to the type of information 
being exchanged.  They also provide well-documented national 
practice exceptions such as the use of inches, feet, and miles for 
pressure, clouds, and visibility in United States aviation 
weather.

   In another word, brevity.

   When these codes were invented, back in the age of mechanical 
teleprinters, 50 WPM wasn't bad and 75 was screaming.  There was 
no alternative to compact coding systems, if weather wires were to 
move a whole world's information in anything approaching a timely 
manner.  After all, nothing's older than yesterday's weather 
forecast.

   Extreme brevity is no longer as important in an age of real-
time binary observations being plotted in 3 dimensions on wide-
area networked computer screens, but standardization is.  
Standards are currently maintained by the World Meteorological 
Organization, a UN body in Geneva with over 150 members.  Changes 
are periodically agreed on and codified in the canonic WMO 
Handbook No. 306, available from the WMO web site.  (Be ready to 
pay in Swiss francs.)

   Most current issues in the text-based communications have to do 
with the very gradual changeover from the practices of different 
countries into the more standard WMO formats.  These changes are 
minor.  In the US, for example, the two big ones are the switch to 
Celsius in reporting airport temperatures and dewpoints, and a 
gradual change from one bulletin heading syntax to another.

1. Weather Bulletin Structure
=============================

   Most of the world's thousands of different weather reports use 
a standard format.  The United States is adopting this, however 
slowly, for its 6000+ products.

   Here's an example of the kind of thing one will copy on utility 
radio stations.  Landlines (the "weather wire" aka the "big wire") 
and computer servers use very similar structures:

ZCZC
SAUS80 KWBC 011200 RRC
METAR
KDAL 011150Z 00000KT SKC 14/11 A3010 RMK 10170 20133=
[more lines of data]
NNNN

Item One : START SIGNAL
-----------------------
       In this example: ZCZC
       Some standard starting signal such as a Telex code, ASCII
string, or whatever is used by the particular network.

Item Two: STANDARD INTERNATIONAL HEADER (in WMO format)
-------------------------------------------------------
       In this example: SAUS80 KWBC 011200 RRC
       The header identifies the type of product, and to whom it 
applies.
       Syntax:
    
         TTLLii CCCC DDHHMM (BBB),

where TT=Type, LL=Location, ii=Number, CCCC=Collection center ID, 
DDHHMM = date/time group of day/hour/minute, and (BBB) is an extra 
information string not always used.

   These headers contain a great deal of information in their 
compact text strings, with many characters pointing into the 
infamous "WMO tables" of very highly organized information on just 
about every weather possibility anywhere in the world.
   There are a number of computer programs, and even web sites, 
that allow the decoding of these headers.  One drops the header 
into a text box and gets back several lines of information.  A 
useful decoder of this type is at the US National Weather Service 
site.  The URL is:

http://www.nws.noaa.gov/oso/hdecode.shtml.

   Sometimes US bulletins have a slightly different header, either 
by itself or next to the WMO format.  This is the notorious "AFOS 
PIL," formerly the standard wire ID for all US weather product.
   AFOS is the Automated Field Operations and Services network 
used since 1982, currently being phased out for AWIPS, the 
Advanced Weather Interactive Processing System.  AFOS uses an 
older ID number called the PIL for "Product Inventory Lookup," but 
all AWIPS communications will use either the WMO style or both.

Item 3: Text
------------
       The content of the bulletin.
       In our example:
       METAR
KDAL 011150Z 00000KT SKC 14/11 A3010 RMK 10170 20133=
[.]

   METAR is a code specifier, indicating that the following lines 
of data will be in the METeorological observation, Aviation, 
Routine format, as currently set forth in WMO standard code FM 15-
IX, Extended.  This is a very common single-line format for hourly 
aviation reports.  If more timely information needs to be passed 
it's done in the similarly structured SPECI (SPECIal weather 
change notice, WMO FM-16).  There are also standards for TEMPO 
(TEMPOrary), and TAF (Terminal Aerodrome Forecast).  For example, 
FTUS in a header always means a standard set of TAF.
   Since METARs use a lot of plain text, it's easy to decode them 
in your head.  In fact, their expansion into ordinary language 
provides much of the ATIS (Automated Terminal Information System) 
and VOLMET ("Flying Weather") transmissions we hear.  They can 
also be automatically stored on web sites that provide weather 
information for pilots, and expanded when looked up.
   For a start, KDAL is the 4-letter ICAO international airport 
identifier (for Love Field, Dallas, TX).  The next two groups are 
a date/time stamp and a wind direction/speed, followed by a number 
of observations that change with type of weather station and 
country.  Finally there's an optional RMK (ReMarKs) field followed 
by the appropriate codes for things like storm activity, dust, 
snow, and such.  The = at the end of the METAR is a terminator, 
corresponding roughly to the old CW BT (short-break) signal.
   The key word in METAR is Routine.  Significant, non-routine, 
weather features that affect aviation will be passed in numbered 
warnings called SIGMET, for SIGnificant METeorological.  It the 
US, these are divided into convective SIGMETs (thunderstorms, 
tornadoes) and non-convective SIGMETs (turbulence, icing, etc.).
    Along with all these aviation formats, we will also see 
surface synoptic observations in their own codes.  These will be 
designated as AAXX or SYNOP (land synoptic code, WMO FM-12), and 
BBXX or SHIP (ship synoptic code, WMO FM-13)  Moored weather buoys 
can be treated as stationary ships.  Drifting ones, or those with 
special observations, have a BUOY code (SSVX, WMO FM-18X , 
replaces DRIFTER) for them.
   We'll have way more about all these codes.

Item 4: End-Of-Message signal
-----------------------------
       A standard ending signal such as the NNNN in our example.

2. Special Weather Identifiers
==============================

   Weather stations use three different types of identifiers.  One 
is the numeric WMO form that we see in some data fields.  These 
can be looked up in a list available online or from WMO as a 
loose-leaf publication that is updated frequently by subscription.  
The list is hundreds of pages long in ASCII text, unfortunately, 
so it is not reproduced here.

   Another is the radio callsign, which we typically see only for 
Volunteer Observation System (VOS) "ships of opportunity," which 
have agreed to put certain standard instruments aboard and train 
one or more crew members in their proper use.  The Beaufort wind 
arrows and sky condition reports shown on oceanic weather charts 
are usually labeled with these callsigns, as are their synoptic 
reports in SHIP code.

   Sometimes a hurricane warning or other advisory will also show 
the callsign of a VOS ship whose report has been used.  These are 
the only times, typically, that radio calls appear in a weather 
product.  WMO maintains a database of those callsigns.  A 
semicolon-delimited record dump from 1999 is available on their 
web site, or a subscription can be purchased for more timely data.

   More important for our uses, though, are the 4-letter 
identifiers that show in the CCCC field of bulletin headings, or 
in the source field of many coded observations.  These look like 
radio callsigns, but they are international IDs that happen to 
mimic the ICAO 4-letter airport convention, and in fact actually 
use it in the case of civilian airport METARs.  However, many of 
these identifiers can also refer to central weather offices, 
information collection and relay points, or even automated 
instruments in the field.

   CONUS airports form the 4-character ICAO ID by prepending K to 
the three-letter IATA identifiers we're used to seeing on our 
baggage.  Alaskan IDs begin with PA, Hawaiian with PH, and Puerto 
Rico with TJ.

   The actual callsigns of the transmitters subsequently used to 
pass information from this system will vary.  Many US military 
broadcasts are in fact completely unidentified except for the 
product sources in the headers, which have nothing to do with who 
ultimately broadcasts the information.

   US military transmitters are usually at Elkhart, NE, near 
Offutt Air Force Base; Saddlebunch Key, near the Key West Naval 
Communication Station; Roosevelt Roads, the US Navy base in Puerto 
Rico.  Schedules change almost weekly, as all remaining US 
military HF weather transmissions are by request from the fleet or 
the Air Force.

   Here are some commonly seen identifiers:

ID    Country/Agency   Office
----  ---------------  ----------------------------------------
AMMC  Australia        Bureau Of Meteorology, Brisbane
BABJ  China            Beijing
CWAO  Canada           Canadian Met. Centre, CN
CWEG  Canada           Alberta Weather Centre, AB
CYYZ  Canada           Toronto Weather Centre, ON
EBBR  Belgium          Brussels
EDZW  Germany          Met. Communications Office
EGRR  UK               British Met. Office, Bracknell, GB
EHAM  Netherlands      Amsterdam
EKMI  Denmark          Met. Institute
FABL  South Africa     Bloemfontein
FAJS  South Africa     Johannesburg
FAPR  South Africa     Pretoria
KAWN  US Air Force     Aviation Weather Network, Offutt AFB, NE
KGWC  US Air Force     Global Weather Center, Offutt AFB, NE
KKCI  NWS/NCEP         Aviation Weather Center, Kansas City, MO
KMKC  NWS/NCEP         SIGMET Center, Kansas City, MO
KNGU  US Navy          US Navy Weather Center, Norfolk, VA
KNHC  NOAA/NWS/NCEP    National Hurricane Center, Tropical
                        Prediction Center, FL
KWBC  NWS/NCEP         NWS Central Operations, MD
KWBx  NCEP             Output from NWS models, per table below
KWNC  NWS/NCEP         Climate Prediction Center
KWNO  NWS/NCEP         Aviation Weather Center, Kansas City, MO
KWNS  NWS/NCEP         Storm Prediction Center
LEMM  Spain            Met. Communication Center, Madrid
LFPW  Meteo France     Met. Center, Toulouse
LIIB  Italy            Met. Communication Center, Rome
LIMC  Italy            Milan
LOWM  Austria          TAF, Surface Observations
MMGL  Mexico           Guadalajara/Miguel Hidalgo y Costilla
                        Int'l (See Mexican METAR sources below)
MMMD  Mexico           Merida/Lic. Manuel Crecencio Rejon Int'l
MMMX  Mexico           Mexico/Lic. Benito Juarez Int'l
MMMZ  Mexico           Mazatlan/General Rafael Beulna Int'l
MNMG  Nicaragua        Managua, Surface Observations
MPTO  Panama           Tocumen, Surface Observations
MYNN  Bahamas          Nassau METAR, Bahamas
NZKL  New Zealand      Metservice Wellington, NZ
NZWN  New Zealand      Wellington
PAFA  NWS/NCEP         Fairbanks, AK
PAJN  NWS/NCEP         Juneau, AK
PANC  NWS/NCEP         Anchorage, AK
PHNL  NWS/NCEP         Honolulu, HI
RJAA  Japan            New Tokyo Airport
RJTD  Japan            Japanese Met. Agency, Tokyo
RPLL  Philippines      Aquino International Airport
RUMS  Russia           Moscow
SABM  Argentina        Natl. Met. Office, Buenos Aires 
SBBR  Brazil           INMET, Brasilia Airport
TJSJ  NWS/NCEP         Puerto Rico
TJNR  US Navy          Roosevelt Roads Naval Station, PR
TTPP  Trinadad&Tobago  Caribbean METAR
VTBB  Thailand         Bangkok METAR
YBBN  Australia        Airport Met. Office, Brisbane
YMMC  Australia        Met. Centre, Melbourne

In KWBx, (x) can be:
 C = NCEP AVN and all other products not listed below
 D = Eta/Early Eta
 E = ETA/mesoEta
 F = Nested Grid Model
 G = Rapid Update Cycle
 H = Medium Range Forecast Model
 I = Sea Surface Temperature Analysis
 J = Wind/Wave model
 K = ENS/Global Ensemble FCST
 L = ENS/Regional Ensemble FCST
 M = Ocean Analysis Models
 N = Ocean Forecast Models
 O = Merge of Models
 Z = NCEP "tiles" from models

Mexican METAR sources are as follows:

SAMX41 MMMX
METAR
MMAA - Acapulco/General Juan N. Alvarez Int'l
MMBT - Bahias Dehuatulco
MMCB - Cuernavaca
MMMX - Mexcio/Lic. Benito Juarez Int'l
MMOX - Oaxaca
MMPA - Poza Rica
MMPB - Puebla
MMPS - Puerto Escondido
MMQT - Queretaro
MMTL - Tulancingo
MMTM - Tampico/General Francisco Javier Mina Int'l
MMTO - Toluca/Lic. Adolfo Lopez M.
MMVR - Veracruz/General Heriberto Jara Int'l
MMZH - Zihuatanejo

SAMX42 MMGL
METAR
MMAS - Aguascalientes
MMEP - Tepic
MMGL - Guadalajara/Miguel Hidalgo y Costilla Int'l
MMIA - Colima
MMLO - Del Bajio/Int'l Guanajuato
MMMM - Morelia
MMPN - Uruapan
MMPR - Puerto Vallarta/Lic. Gustavo Dias Ordaz Int'l
MMSP - San Luis Potosi
MMZC - Zactecas
MMZO - Manzanillo Int'l

SAMX43 MMMZ
METAR
MMCL - Culiacan
MMCN - Ciudad Obregon
MMDO - Durango
MMGM - Guaymas/General Jose Maria Yanez Int'l
MMHO - Hermosillo/Int'l
MMLM - Los Mochis
MMLP - La Paz/General Manuel Marquez de Leon Int'l
MMLT - Loreto Int'l
MMML - Mexicali/General Rodolfo Sanchez Taboada Int'l
MMMZ - Mazatlan/General Rafael Beulna Int'l
MMSD - San Jose del Cabo Int'l
MMTJ - Tijuana/General Abelardo L. Rodriguez Int'l

SAMX44 MMMD
METAR
MMCE - Ciudad del Carmen
MMCM - Chetumal Int'l
MMCP - Campeche
MMCZ - Cozumel/Int'l
MMMD - Merida/Lic. Manuel Crecencio Rejon Int'l
MMMT - Minatitlan
MMTG - Tuxtla Gutierrez (mil)
MMTP - Tapachula Int'l
MMUN - Cancun Int'l
MMVA - Villahermosa

SAMX45 MMMY
METAR
MMAN - Monterrey Int/Aeropuerto del Norte
MMCS - Ciudad Juarez/Abraham Gonzales Int'l
MMCU - Chihuahua/Int'l
MMCV - Ciudad Victoria
MMIO - Satillo
MMMA - Matamoros/Int'l
MMMY - Monterrey/General Marianao Escobedo Int'l
MMNL - Nuevo Laredo Int'l
MMRX - Reynosa/Genral Lucio Blanco Int'l
MMTC - Torreon Int'l.

3. A Few North American Military Weather Frequencies
====================================================

   Most frequencies are assigned channel center.  The dial/window 
frequency for FAX is usually 1.9 kHz lower, as we tune it in USB.  
RTTY can vary as much as 2 kHz either way, depending on receiver 
and habits of the operator.

   RTTY is 850 Hz shift, 75 baud, ITA2 Baudot code.  FAX is 120 
lines per minute, with an Index Of Cooperation of 576.  The US Air 
Force transmissions are not necessarily parallel, and not all 
frequencies are in use at all times.

   This list is far from exhaustive, and frequencies change a 
couple of times in the average year.  Consult Internet and 
published lists for more recent data.

 3231.0  KAWN  RTTY (Tune in LSB)
 3131.0  KGWC  FAX  (Tune in USB)
 4271.4  CFH   FAX  (Canadian Forces, Halifax; also RTTY)
 4855.0  KGWC  FAX
 6496.4  CFH   FAX  (Canadian Forces, Halifax; also RTTY)
 7398.0  KGWC  FAX
 7784.0  KAWN  RTTY
 7870.0  KGWC  FAX
10536.0  CFH   FAX  (Canadian Forces, Halifax; also RTTY)
11120.0  KAWN  RTTY (Tune in LSB)
11120.0  KGWC  FAX  (Tune in USB)
13510.0  CFH   FAX  (Canadian Forces, Halifax; also RTTY)
13530.0  KAWN  RTTY
15781.0  KGWC  FAX
19324.5  KAWN  RTTY
19363.0  KGWC  FAX
19530.0  KAWN  RTTY (Usually "fox" marker)

4. "Old" Bulletin Type Codes
============================

   These use the first two letters TT in the group TTLLii at the 
beginning of the heading.  These provide a quick indication most 
of the time, but WMO has subsequently adopted a far more detailed 
system which we will see in the appendices to this document.

Syntax: TTLL, where: 

TT       Explanation
======   ===========
AB       Weather summaries
AC       Convective outlooks
AS       Surface analyses
AU       Upper level analyses
AX       Tropical discussions
CS       Climatic data
CU       Upper air climatic data
FA       Area forecasts
FB       Aviation forecasts
FC       Recovery forecasts
FD       Winds aloft forecasts
FE       Extended forecasts
FK       Air stagnation forecasts
FO       Model output forecasts
FP       Public forecasts
FQ       Metropolitan forecasts
FS       Surface forecasts
FT       Terminal forecasts
FU       Upper level forecasts
FV       Avalanche forecasts
FW       Recreational forecasts
FX       Prog discussions
FZ       Marine forecasts
NF       Special notices
NO       General notices
RW       River conditions, flood info and forecasts
SA       Surface observations
SD       Radar observations
SE       Earthquake observations
SF       Sferics weather data
SH       Synoptic ship reports
SI       Intermediate synoptic reports
SM       Synoptic observations
SP       Special reports
SR       River and rainfall observations
SS       Ship reports
ST       Ice reports
SX       Miscellaneous observations
TB       Satellite data
UA       Pilot reports
UC,UE,UF Upper air data from ships
UG,UH,UI Pibal/Rawinsonde data
UJ,UK,UM Radiosonde data
UN,UQ    Radiosonde data
UP       Pibal/Rawinsonde data
UR       Aircraft reconnaissance data
US,UW,UX Radiosonde data
UT       Aircraft reports
UY,UZ    Upper air data
WF       Tornado warnings
WO       Tropical depression advisories
WR       Flash flood warnings
WS       Sigmets
WT       Tropical storm/hurricane advisories
WU       Severe thunderstorm warnings
WW       Special weather statements and weather watches

5. WMO Heading Regional Codes

   These are used in most bulletin headings in the LL or AA part 
of the TTLLii / TTAAii group.

LL       Region
==       ======
AB       Albania
AG       Argentina
AH       Afghanistan
AI       Ascension Island
AJ       Azerbaijan, Republic of
AK       Alaska
AL       Algeria
AN       Angola
AT       Antigua, St. Kitts & British islands in the vicinity
AU       Australia
AY       Armenia. Republic of
AZ       Azores Islands
BA       Bahamas
BC       Botswana
BD       Brunei Darussalam
BE       Bermuda
BG       Bosnia & Herzegovina
BH       Belize
BI       Burundi
BJ       Benin
BK       Banks Islands
BM       Myanmar (Burma)
BN       Bahrain
BO       Bolivia
BR       Barbados
BU       Bulgaria
BV       Bouvet Island
BW       Bangladesh
BX       Belgium, Luxembourg
BY       Belarus, Republic of
BZ       Brazil 
CD       Chad
CE       Central African Rep
CG       Congo
CH       Chile
CI       China
CM       Cameroon
CN       Canada
CR       Canary Islands (Spain)
CS       Costa Rica
CT       Canton Island
CU       Cuba
CV       Cape Verde Islands
CY       Cyprus
CZ       Czech Republic
DJ       Djibouti
DL       Germany
DN       Denmark
DO       Dominica
DR       Dominican Republic
DY       Democratic Yemen
EG       Egypt
EO       Estonia
EQ       Ecuador
ER       United Arab Emirates
ES       El Salvador
ET       Ethiopia
FA       Faeroes Islands
FG       French Guyana
FI       Finland 
FJ       Fiji Islands
FK       Falkland Isl. (Malvinas)
FP       Saint Pierre Island & Miquelon
FR       France  
FW       Wallis and Futuna Isl.
GB       Gambia
GC       Cayman Islands
GD       Grenada 
GE       Gough Island
GG       Georgia, Republic of
GH       Ghana
GI       Gibraltar
GL       Greenland
GM       Guam Island
GN       Guinea
GO       Gabon
GQ       Equatorial Guinea
GR       Greece
GU       Guatemala
GW       Guinea-Bissau
GY       Guyana
HA       Haiti
HE       St. Helena Island
HK       Hong Kong
HO       Honduras
HU       Hungary
HV       Burkina Faso
HW       Hawaiian Islands
IC       Comoros
ID       Indonesia
IE       Ireland
IL       Iceland
IN       India
IQ       Iraq
IR       Iran
IS       Israel
IV       Cote d'Lvoire
IY       Italy
JD       Jordan
JM       Jamaica
JP       Japan
KA       Caroline Islands
KB       Kiribati
KG       Kirgiristan, Republic of
KI       Christmas Islands
KK       Cocos Islands
KN       Kenya 
KO       Korea, Republic of
KP       Cambodia
KR       Democratic People's Republic of Korea
KU       Cook Island
KW       Kuwait  
KY       Kyrghyzstan, Republic of
KZ       Kazakhstan,Republic of
LA       Lao People's Democratic Rep
LB       Lebanon 
LC       Saint Lucia
LI       Liberia 
LJ       Slovenia
LN       Southern Line Islands
LS       Lesotho 
LT       Lithuania
LV       Latvia 
LY       Libyan Arab Jamahiriya
MA       Mauritius
MB       Marion Island
MC       Morocco
MD       Madeira Island
MF       Saint-Martin, Saint-Bartholomew, Guadeloupe, etc
MG       Madagascar  
MH       Marshall Islands
MI       Mali
MJ       Former Yugoslav Rep. of Macedonia
ML       Malta
MN       St.Maarten, St.Eustatius & Saba
MO       Mongolia
MR       Martinique Island
MS       Malaysia
MT       Mauritania
MU       Macao
MV       Maldives Islands 
MW       Malawi
MX       Mexico
MY       Mariana Islands
MZ       Mozambique
NC       New Caledonia Island
NG       Papua New Guinea
NI       Nigeria
NK       Nicaragua
NL       Netherlands
NM       Namibia
NO       Norway
NP       Nepal
NR       Niger
NU       Netherlands Antilles (Aruba, Bonaire, Curacao)
NV       Vanuatu
NW       Nauru Island
NZ       New Zealand
OM       Oman 
OR       South Orkney Islands
OS       Austria 
PF       French Polynesia Islands
PH       Philippines
PI       Phoenix Islands
PK       Pakistan
PL       Poland
PM       Panama
PO       Portugal
PR       Peru
PT       Pitcairn Island
PU       Puerto Rico
PY       Paraguay
QT       Qatar
RA       Russia, Republic of (East)  
RE       Reunion and assoc. islands
RH       Croatia
RM       Republic of Moldova
RO       Romania
RS       Russia, Republic of (West)
RW       Rwanda
SB       Sri Lanka
SC       Seychelles Islands
SD       Saudi Arabia
SG       Senegal
SI       Somalia
SK       Sarawak
SL       Sierra Leone
SM       Suriname 
SN       Sweden
SO       Solomon Islands
SP       Spain 
SQ       Slovakia 
SR       Singapore
SU       Sudan 
SV       Swaziland 
SW       Switzerland
SX       Santa Cruz Island
SY       Syria 
SZ       Spitzbergen Islands
TC       Tristan da Cunha
TD       Trinidad and Tobago
TG       Togo
TH       Thailand 
TI       Turks and Caicos Islands
TK       Tokelau Islands
TM       Timor 
TN       Tanzania, United Rep of
TO       Tonga
TP       Sao Tome and Principe
TR       Turkmenistan, Republic of
TS       Tunisia
TU       Turkey
TV       Tuvalu
TZ       Tajikistan, Republic of
UG       Uganda
UK       United Kingdom of Great Britain and Northern Ireland
UR       Ukraine, Republic of
US       United States of America
UY       Uruguay
UZ       Uzbekistan, Republic of
VG       St. Vincent and the Grenadines
VI       Virgin Islands
VN       Venezuela
VS       Vietnam 
YE       Yemen
YG       Yugoslavia
ZA       South Africa
ZB       Zambia
ZM       Western Samoa
ZR       Zaire
ZS       American Samoa
ZW       Zimbabwe

6. Full List Of Weather Codes
=============================

Text-Based Codes
----------------

   Text-based codes pass data as letters and numbers 
(alphanumerics), as opposed to a continuous bit stream.  They are 
usually broken up into standard groups for readability.
   Baudot (ITA2), SITOR, and ASCII (ITA 5) are examples of text-
based transmission modes.  These codes are usually substitutions 
into lookup tables of longer strings or amounts, though 
occasionally raw data is transmitted this way, as numbers or 
encoded into alphanumerics that represent the appropriate binary 
bits for direct crunching by computers.

SYNOP             (WMO FM-12)   Surface Synoptic Reports
SHIP              (WMO FM-13)   Ship Synoptic Reports

                  Both of the above use a ship callsign or a
                  WMO sea or land station number, followed by a
                  time stamp. Up to four more sections follow,
                  in 5 number groups except for the word ICE + a
                  short text string, if ice observations are
                  being passed in that section of the synopsis.

METAR             (WMO FM-15)   Aviation Routine Observations
                  Hourly reports, usually at airports.

SPECI             (WMO FM-16)   Special Aviation Weather Change
                  For important changes before the next scheduled
                  METAR.  Expands to word "SPECIAL" in voice ATIS
                  or VOLMET, both of which use an altered METAR
                  format.

DRIFTER           (WMO FM-18IX) Drifting Buoy Obs, now BUOY

BUOY              (WMO FM-18X)  Buoy Observations
                   Weather buoys can be treated as ships and
                   pass data in SHIP code, or use this special
                   format labeled SVXX in bulletins.

RADOB             (WMO FM-20)   Radar Observations
RADREP            (WMO FM-22)   Radiological Data

PILOT             (WMO FM 32)   Upper Level Wind
PILOT SHIP        (WMO FM 33)   Upper Level Wind
PILOT MOBIL       (WMO FM 34)   Upper Level Wind
TEMP              (WMO FM-35)   Upper Level Observations
TEMP SHIP         (WMO FM-36)   Upper Level Observations
TEMP DROP         (WMO FM-37)   Aircraft Dropsonde Obs.
TEMP MOBIL        (WMO FM-38)   Upper Level Observations

ROCOB             (WMO FM-39)   Rocketsonde Reports
ROCOB SHIP        (WMO FM-40)   Rocketsonde Reports

CODAR             (WMO FM-41)   Aircraft Report
AMDAR             (WMO FM-42)   Aircraft Report
ICEAN             (WMO FM-44)   Ice report
IAC               (WMO FM-45)   Ship surface observation
IAC FLEET         (WMO FM-46)   Ship surface observation

GRID              (FM 47-IX Ext)   Gridded Data (sent as text)
                  GRID provides observation data and information
                  on how to plot it.  The result is a picture.

WINTEM            (WMO FM-50)   Upper-level Winds, Temperatures

TAF               (WMO FM-51)   Terminal Aerodrome Forecasts
                  A series of standard groups for valid times,
                  starting FM "(in voice, "from") for the first,
                  then with BCMG (in voice, "becoming,").  If
                  weather is expected to change before the first
                  valid time, a TEMPO ("temporarily") group is
                  included.  TAF, when expanded into plain speech,
                  is part of the VOLMET.

ARFOR             (WMO FM-53)   Aviation Routine Forecasts
ROFOR             (WMO FM-54)   On-Route Aviation Forecasts
RADOF             (WMO FM-57)   Radiological Dose Predictions
MAFOR             (WMO FM-61)   Shipping Area Forecasts

TRACKOB           (WMO FM-62)   Oceanographic Data
BATHY             (WMO FM-63)   Oceanographic Data
TESAC             (WMO FM-64)   Oceanographic Data
WAVEOB            (WMO FM-65)   Oceanographic Data

HYDRA             (WMO FM-67)   Hydrological River Reports
HYFOR             (WMO FM-68)   Hydrological Forecast

CLIMAT            (WMO FM-71)   Surface climatic data
CLIMAT SHIP       (WMO FM-72)   Surface marine climatic data
NACLI, CLINP,
SPCLI, CLISA,
INCLI             (WMO FM-73)   Oceanic climatic data
CLIMAT TEMP       (WMO FM-75)   Upper-air climatic data
CLIMAT TEMP SHIP  (WMO FM-76)   Upper-air marine climatic data

SFAZI             (WMO FM-81)   Special Atmospheric Reports
SFLOC             (WMO FM-82)   Special Atmospheric Reports
SAREP             (WMO FM-85)   Satellite Cloud Interpretations
SATEM             (WMO FM-86)   Satellite Remote Upper Soundings
SARAD             (WMO FM-87)   Satellite Radiance Observations
SATOB             (WMO FM-88)   Satellite Temps & Radiance Balance

CREX              (None A.P.)   Coded raw data table driven obs.

AIRMET                          Aviation Weather Advisory
                  Like a SIGMET, in a special clipped text format,
                  but for less serious weather features.

AIREP                           ICAO Air Report, like a PIREP

PIREP                           Pilot Report of standard items
                  PIREPs go into a database, to be used by weather
                  offices when briefing pilots.

RECCO                           Aircraft Reconnaissance Report
                  One important use of the RECCO format is for
                  data returned by hurricane aircraft every 30
                  minutes.

TEMPO                           Rapidly Changing Weather
                  TEMPO is usually part of a TAF, describing
                  weather expected to change within the hour.

SIGMET                          SIGnificant METeorological warning
                  A weather feature that poses a hazard to
                  aviation. In the US, divided into convective
                  (severe thunderstorms or tornadoes), and non-
                  convective (things like turbulence and icing).
                  Interestingly, SIGMET is also an officially
                  defined hypertext markup document type.
                  SIGMETs are in a clipped text format.

VORTEX                          Aircraft Hurricane Observations
                  Data passed from dropsonde aircraft while on
                  the actual pass through the hurricane, including
                  position fix, pressure, wind, and eye structure.

Binary Codes
-----------

BUFR              (WMO FM-94)   Binary Universal Form for the
                                 Representation of met. data
                  BUFR is a completely binary code for computer
                  crunching, passing data in octets as a binary
                  stream, beginning with the designator BUFR in
                  CCITT ITA5)

GRIB              (FM 92-IX Ext)   Gridded Binary Data
                  GRIB provides observation data and information
                  on how to plot it, but unlike GRIB the data is
                  intended for computer crunching alone.  It, too
                  is passed as octets, but in a text form these
                  can show as hexadecimal bytes 00 through FF.
                  The result looks like a "hex dump" with numbers
                  and letters A through F.

7. Weather Code FAQ
===================

Here are some common questions seen on Internet, and in mail to
Utility World:

1. Q. I found an unid RTTY transmission that looks like "numbers," 
but the format is weird and some groups have letters.
   A. Look for things we've talked about, like AAXX, BBXX, METAR,
SPECI, TEMPO, or KAWN, and you might be surprised.

2. Q. I went to the Air Force frequencies you wrote about, but 
nothing happened.
   A. Since all US HF military weather is on request, the 
schedules and frequencies are nearly as changeable as, well, the 
weather.

3. Q. I found the US Air Force FAX you talk about, and I seem to 
be in sync, but all I get is a skinny white line.
   A. A lot of these faxes are apparently some sort of raster 
grid, and if there's no significant weather to plot, all that 
comes out on the amateur's typical computer screen is the sync 
beep at the edge.  When there is significant weather, it can 
show up as standard synoptic symbols such as the two lines and a 
jagged arrow meaning "thunderstorm," or as a number, presumably 
for a SIGMET or similar.
   Everything else is black, except for a few groups looking like 
WMO headers, and maybe a couple of chicken scratchings that are there
just because the equipment does these things.
   This is a good reason not to leave the printer on for Air Force 
weather fax.

4. Q. I'm getting good copy of the RTTY, but it's all numbers and 
doesn't fit any of these codes.
   A. Yes, you've noticed this too. My guess is that it's raw 
output in some military version of something like GRID, GRIB, or 
BUFR.

5. Q. So where is the KAWN transmitter anyway?
   A. It's wherever the US Air Force Automated Weather Network, 
formerly the Aviation Weather Network, is being picked up and 
relayed onto the radio.  Since KAWN is not a radio callsign, it 
contains no information as to transmitter locations.  The same 
holds for KGWC, KNHC, etc..

6. Q. What is QNH?
   A. Altimeter setting in international and/or Metric units.  
Below a certain altitude, pilots manually offset their altimeters 
to compensate for changing barometric pressures which would 
otherwise cause measurement errors.  It comes from an old 
international procedural "Q" signal from the days of Morse code.  
Simplified meaning of the old prosign is:

    QNH? = "What is your station's altimeter setting (usually in
           Hectopascals) [at -?]," and
    QNH  = "Set your altimeter to - [at - hours]."

   In the US national practice, "Altimeter" is substituted for 
"QNH," and the unit is inches of mercury.  This is one way to tell 
whether a voice bulletin is coming from the US or somewhere else.

8. Useful WWW URLs
==================

BUFR Code Specifications:
http://www-dd.fsl.noaa.gov/bufrFormat.html

Details of "Hurricane Hunter" use of RECCO and VORTEX codes:
http://www.hurricanehunters.com/

Entry point into weather station designator database:
http://www.nws.noaa.gov/oso/oso1/oso12/siteid.htm

NCDC Weather Station Locator:
http://www.ncdc.noaa.gov/ol/climate/stationlocator.html

SHIP synoptic code, with US Navy extensions
http://waves.ncdc.noaa.gov/ship/sec1-ch1.htm

Terminal Aerodrome Forecast code:
http://www.nws.noaa.gov/oso/oso1/oso12/d31/D31links.htm

UK Meteorological Office:
http://www.met-office.gov.uk/index.html

US Federal Meteorological Handbook:
http://www.nws.noaa.gov/oso/oso1/oso12/fmh1.htm

WMO Technical Library:
http://www.wmo.ch/web/arep/lib1/index.html

Appendices to this document
===========================

1. Full WMO Heading Decoder
2. Guide to the (BBB) Codes
3. The METAR Code
4. The SYNOP Code
5. The SVXX/BUOY Code

Appendix #1: Full WMO Heading Decoder, With Tables
==================================================

The FULL symbolic form of the WMO abbreviated heading is:

                T1T2A1A2ii CCCC YYGGgg (BBB)

   The full lookup format for the WMO Abbreviated Heading uses a 
format where the first character of the "Type" field (T1) becomes 
the key to what the subsequent characters mean, and then some of 
these can also affect what happens next.  This is how a 6-
character group can store so much information.

   The key list of T1 values is Table A from WMO Manual 306, 
(Code) or Observing / Product Type.  It's best visualized as a 
matrix of jumps to subsequent tables, so that's just what we'll 
do. Get the first letter T1 from your bulletin, then look across 
to determine how to interpret subsequent characters, then drop 
down to the appropriate table and find them.

   If this whole thing looks like a potentially good use for 
hypermedia like HTML code, well, it's been done.  Try the US 
web site at http://www.nws.noaa.gov/

TABLE A
Data Type Designator T1 Matrix Table
for
T2A1A2ii   definitions 
T1  Data type            T2    A1   A2   ii   Priority   Max Lgth
A   Analyses             B1    C1   C1   **       3       3800
B   Service message     ***   ***  ***  ***    1/2/4*     3800
C   Climatic data        B1    C1   C1   **       4       3800
D   Grid point
    information (GRID)   B2    C3   C4   D2       3       3800
E   Satellite imagery    B5    C1   C1   **       3       (1)
F   Forecast             B1    C1   C1   **       3       3800
G   Grid point
    information (GRID)   B2    C3   C4   D2       3       3800
H   Grid point
    information (GRIB)   B2    C3   C4   D2       3     15,000
I   Binary observation
     - BUFR              B3    C6   C3   **       3     15,000
J   Binary forecast
     - BUFR              B3    C6   C3   **       3     15,000
K   CREX                 C7    C7   C3   **       2       3800
L   -- 
M   -- 
N   Notices              B1    C1   C1   **       4       3800
O   Oceanographic (GRIB) B4    C3   C4   D1       3     15,000
P   Pictorial
    information(binary)  B2    C3   C4   D2       3     15,000
Q   Pictorial
    information regional B2    C3   C5   D2       3       (1)
R   -- 
S   Surface data         B1    C1/C2 C1/C2 **     2/4*    3800
T   Satellite data       B1    C3   C4     **     2       3800
U   Upper-air data       B1    C1/C2 C1/C2 **     2       3800
V   National data        (3)   C1   C1     **    (2)      (1)
W   Warnings             B1    C1   C1     **     1       3800
X   GRID regional use    B2    C3   (2)    D2     3       3800
Y   GRIB regional use    B2    C3   (3)    D2     3     15,000
Z   GRIB National use    (3)   (3)  (3)    (3)    3     15,000

* Priority level: 

1 is allocated to service messages 
2 is allocated to data and request messages 
4 is allocated to seismologic data (T1T2 = SE) or administrative 
messages 
**  See Para.2.3.2.2 (of WMO manual) for definition and use
*** See Para.2.4.2.3 for definition and use

(1) Size to be defined at a later date
(2) To be determined later date
(3) Table B2 or national table

DATA TYPES Y and Z uses National tables in some countries

This then selects one of the following:

Table B1 - Data Type Designator 
Table B2 - Data Type Designator 
Table B3 - Data Type designator 
Table B4 - Data Type Designator 
Table B5 - Data Type Designator 
Table C1 - Geographical Designator 
Table C2 - Geographical Designator (ships & Ocean) 
Table C3 - Geographical Designator 
Table C4 - Reference Time Designator 
Table C5 - Reference Time Designator 
Table C6 - Data Type Designator 
Table C7 - Geographical Designator 
Table D1 - Level Designator (ocean) 
Table D2 - Level Designator 
and

U.S. National Tables

Table B6   - Data Type Designator 
Table C8   - Geographical Area Designator (including WMC
              Washington GRID Numbers) 
Table C9   - Geographical Area (Tiles) used with KWBx when x = Z 
Table C10  - Reference Time Designator  
Table D3   - Level Designator ii 

T1   is taken from WMO Manual 386 table A. It is an alpha 
character that designates the general code form of the contents of 
the bulletin (Coded or plain text).

T2   is taken from WMO Manual 386 tables B1 through B6 depending 
on the designator T1 in table A. It is an alpha character that 
designates the data type.

A1   is taken from WMO Manual 386 tables C1 through C6 depending 
on designator T1 in table A ( U.S. National practice through C9 ). 
It is an alpha character that designates the geographical area the 
content of the bulletin covers.

A2   is taken from WMO Manual 386 tables C1 through C5 depending 
on designator T1 in table A ( U.S. National practice through C9 ). 
It is an alpha character that designates the geographical area, or 
may define the forecast period.

ii   is taken from the WMO Manual 386 paragraph 2.3.2.2 
definition, or from table D1 or D2 depending on designator T1 in 
table A ( U.S. National practice table D3 replaces D2 ). It is a 
numeric set of two characters. Go to the WMO message structure for 
more details on this group.

When the group ii is used as a US designator, which it is not 
always the case, it expands to:

ii = 40, 50, ... 80  Issued from U.S. Pacific WFO
     41, 51, ... 81  Issued from Northeast U.S. WFO or RFC
     42, 52, ... 82  Issued from southeast U.S. WFO or RFC        
                     (Includes San Juan, PR)
     43, 53, ... 83  Issued from North Central U.S. WFO or RFC
     44, 54, ... 84  Issued from South Central U.S. WFO or RFC
     45, 55, ... 85  Issued from U.S. Rocky Mountains WFO or RFC
     46, 56, ... 86  Issued from West Coast WFO or RFC
     47, 57, ... 87  Issued from SE Alaska WFO (Juneau, AK)
     48, 58, ... 88  Issued from Central Alaska WFO or RFC
                     (Anchorage, AK)
     49, 59, ... 89  Issued from NE Alaska WFO (Fairbanks, AK).

CCCC   is the 4-character international code.

YYGGgg   is the standard date/time stamp of day, hours, minutes.

(BBB)   is an optional group of alpha characters, reference BBB 
Group explanation in the next appendix to this document.

Here are the tables for the first group -

T1T2A1A2ii:

Table A
T1:
A   Analyses
B   Service message
C   Climatic data
D   Grid point information (GRID)
E   Satellite imagery
F   Forecast
G   Grid point information (GRID)
H   Grid point information (GRIB)
I   Binary observation - BUFR
J   Binary forecast - BUFR
K   CREX
L   -- 
M   -- 
N   Notices
O   Oceanographic (GRIB)
P   Pictorial information(binary)
Q   Pictorial information regional
R   --
S   Surface data
T   Satellite data
U   Upper-air data
V   National data
W   Warnings
X   GRID regional use
Y   GRIB regional use
Z   GRIB National use

---------------------------------------------------------------
Table B1
T2 (T1 = A, C, F, N, S, T, U or W)
T1 = A Analyses
  C         Cyclone                     [TEXT]
  G         Hydro/Marine                [TEXT]
  H         Thickness                   [TEXT]
  I         Ice                         FM 44 (ICEAN)
  O         Ozone layer                 [TEXT]
  R         Radar                       [TEXT]
  S         Surface          FM 45 (IAC)/FM 46 (IAC FLEET)
  U         Upper air                    FM 45 (IAC)
  W         Weather Summary             [TEXT]
  X         Miscellaneous               [TEXT]

T2 (T1 = C Climatic data):
  A         Climatic anomalies            [TEXT]
  E         Monthly means (upper air)   FM 76 (CLIMAT TEMP SHIP)
  H         Monthly means (surface)     FM 72 (CLIMAT SHIP)
            Monthly means (ocean areas) FM 73 (NACLI, CLINP,
                                              SPCLI, CLISA, INCLI)
  S         Monthly means (surface)     FM 71 (CLIMAT)
  U         Monthly means (upper air)   FM 75 (CLIMAT TEMP)

T2 (T1 = F Forecasts)
  A        Aviation area /GAMET/advisories   FM 53 (ARFOR)/[TEXT]
  B        Upper winds and temperatures      FM 50 (WINTEM)
  C        Aerodrome (VT › 12 hours)         FM 51 (TAF)
  D        Radiological trajectory dose      FM 57 (RADOF)
  E        Extended                                 [TEXT]
  F        Shipping                          FM 46 (IAC FLEET)
  G        Hydrological                      FM 68 (HYFOR)
  H        Upper air thickness                      [TEXT]
  I        Iceberg                                  [TEXT]
  J        Radio warning service (incl IUWDS data)  [TEXT]
  K        Tropical cyclone advisories              [TEXT]
  L        Local/Area                               [TEXT]
  M        Temperature extremes                     [TEXT]
  O        Guidance                                 [TEXT]
  P        Public                                   [TEXT]
  Q        Other shipping                           [TEXT]
  R        Aviation route                    FM 54 (ROFOR)
  S        Surface                    FM 45 (IAC)/FM46 (IAC FLEET)
  T        Aerodrome (VT > 12 hours)         FM 51 (TAF)
  U        Upper air                         FM 45 (IAC)
  V        Volcanic ash advisories                  [TEXT]
  W        Winter sports                            [TEXT]
  X        Miscellaneous                            [TEXT]
  Z        Shipping area                     FM 61 (MAFOR)

T2 (T1=N Notices)
  G        Hydrological                                [TEXT]
  H        Marine                                      [TEXT]
  N        Nuclear emergency response                  [TEXT]
  O        METNO/WIFMA                                 [TEXT]
  P        Product generation delay                    [TEXT]
  T        TEST MSG[System related]                    [TEXT]
  W        Warning related and/or cancellation         [TEXT]
T2 (T1=S Surface Data)
  A        Aviation routine reports               FM 15 (METAR)
  B        Radar reports (part A)                 FM 20 (RADOB)
  C        Radar reports (part B)                 FM 20 (RADOB)
  D        Radar reports (parts A & B)            FM 20 (RADOB)
  E           Seismic data                            (SEISMIC)
  F       Atmospherics reports                    FM 81 (SFAZI)/
                                                  FM 82 (SFLOC)/
                                                  FM 83 (SFAZU)
  G       Radiological data report                FM 22 (RADREP)
  I       Intermediate synoptic hour              FM 12 (SYNOP)/
                                                  FM 13 (SHIP)
  L       Table driven coded reports              FM ?? (CREX)
  M       Main synoptic hour                      FM 12 (SYNOP)/
                                                  FM 13 (SHIP)
  N       Non-standard synoptic hour              FM 12 (SYNOP)/
                                                  FM 13 (SHIP)
  O       Oceanographic data                      FM 63 (BATHY)/
                                                  FM 64 (TESAC)/
                                                  FM 65 (WAVEOB)
                                                  FM 62 (TRACKOB)
  P       Special aviation weather reports        FM 16 (SPECI)
  R       Hydrological (river) reports            FM 67 (HYDRA)
  S       Drifting buoy reports                   FM 18 (DRIFTER)
  T       Sea Ice                                 [TEXT]
  U       Snow depth                              [TEXT]
  V       Lake ice                                [TEXT]
  X       Miscellaneous                           [TEXT]

T2 (T1=T Satellite Data)
  B       Satellite orbit parameters           [TEXT]
  C       Satellite cloud interpretations      FM 85 (SAREP)
  H       Satellite remote upper-air soundings FM 86 (SATEM)
  R       Clear radiance obs                   FM 87 (SARAD)
  T       Sea surface temperatures             FM 88 (SATOB)
  W       Winds & cloud temperatures           FM 88 (SATOB)
  X       Miscellaneous                        [TEXT]
  Y       Radiance Balance                     TM 88 (SATOB)

T2 (T1=U Upper Air Data)
  A       Aircraft reports             FM 41(CODAR), ICAO (AIREP)
  D       Aircraft reports                    FM 42(AMDAR)
  E       Upper-level pressure,               FM 35(TEMP)/
           FM 36 (TEMP SHIP) temperature, humidity and wind 
           (Part D) FM 38(TEMP MOBIL)
  F       Upper-level pressure, temperature,  FM 35(TEMP)/
           FM 36 (TEMP SHIP)/ FM 38 (TEMP MOBIL)humidity and wind
           (Parts C and D) [National and bilateral option]
  G       Upper-wind (Part B)               FM 32(PILOT)/
                                            FM 33 (PILOT SHIP)/
                                            FM 34  (PILOT MOBIL)
  H       Upper-wind (Part C)               FM 32 (PILOT)/
                                            FM 33 (PILOT SHIP)/
                                            FM 34 (PILOT MOBIL)
  I       Upper-wind (Parts A and B)        FM 32 (PILOT)/
                                            FM 33 (PILOT SHIP)/
                                            FM 34 (PILOT MOBIL)
          [National and bilateral option] 
  K       Upper-level pressure, temperature, FM 35(TEMP)/FM 36
           (TEMP SHIP)/FM 38 (TEMP MOBIL) humidity and wind
           (Part B)
  L       Upper-level pressure, temperature,          FM 35
           (TEMP)/FM 36 (TEMP SHIP)/FM 38 (TEMP MOBIL)
           humidity and wind (Part C) 
  M       Upper-level pressure, temperature,          FM 35
           (TEMP)/FM 36 (TEMP SHIP)/FM 38 (TEMP MOBIL)
           humidity and wind (Parts A and B) 
           [National and bilateral option]
  N       Rocketsonde reports               FM 39 (ROCOB)/
                                            FM 40 (ROCOB SHIP)
  P       Upper-wind (Part A)               FM 32 (PILOT)/
                                            FM 33 (PILOT SHIP)/
                                            FM 34 (PILOT MOBIL)
  Q       Upper-wind (Part D)               FM 32 (PILOT)/
                                            FM 33 (PILOT SHIP)/
                                            FM 34 (PILOT MOBIL)
  R       Aircraft report                   [NATIONAL*] (RECCO)
  S       Upper-level pressure, temperature,          FM 35
           (TEMP)/FM 36 (TEMP SHIP) humidity and wind (Part A)
           FM 38 (TEMP MOBIL)
  T       Aircraft report                   FM 41 (CODAR)
  X       Miscellaneous                             TEXT]
  Y       Upper-wind (Parts C and D)        FM 32 (PILOT)/
                                            FM 33 (PILOT SHIP)/
                                            FM 34 (PILOT MOBIL)
                                   [National and bilateral option]
  Z       Upper-level pressure, temperature, FM 37(TEMP DROP),
           humidity and wind from a sonde released by carrier
           balloon or aircraft (Parts A, B, C, D)

T2 (T1=W Warnings)
  A       Airmet                                   [TEXT]
  C       Tropical cyclone (SIGMET)                [TEXT]
  E       Tsunami                                  [TEXT]
  F       Tornado                                  [TEXT]
  G       Hydrological/River Flood                 [TEXT]
  H       Marine/Coastal Flood                     [TEXT]
  O       Other                                    [TEXT]
  S       SIGMET                                   [TEXT]
  T       Tropical cyclone (Typhoon/Hurricane)     [TEXT]
  U       Severe Thunderstorm                      [TEXT]
  V       Volcanic Ash Clouds (SIGMET)             [TEXT]
  W       Warnings & weather summary               [TEXT]

-----------------------------------------------------------------
Table B2
T2 (T1 = D, G, H, P, Q, V, X or Y)
  A            Radar data
  B            Cloud
  C            Clear air turbulence 
  D            Thickness (relative topography)
  E            Precipitation
  F            Aerological diagrams (Ash cloud)
  G            Significant weather
  H            Height
  I            Ice flow
  J            
  K            Swell height + combinations
  L            Plain language
  M            For national use
  N            Radiation
  O            Vertical velocity
  P            Pressure
  Q            Wet bulb potential temperature
  R            Relative humidity
  S            Snow cover
  T            Temperature
  U            Eastward wind component
  V            
  X            Lifted index
  Y            Observational plotted chart
  Z            Not assigned

------------------------------------------------------------------
Table B3
T2 (T1=I or J Binary Data - BUFR)
  S        Surface/sea level
  U        Upper AirOceanographic/limnographic (water properties)
  P        Pictorial
  T        Text (plain language information)
  X        Other data types
  Z        Mixed data types

------------------------------------------------------------------
Table B4
T2 (T1=O Oceanographic - GRIB)
  D        Depth
  E        Ice concentration
  F        Ice thickness
  G        Ice drift
  H        Ice growth
  I        Ice convergence/divergence
  Q        Temperature anomaly
  R        Depth anomaly
  S        Salinity
  T        Temperature
  U        Current component
  V        not assigned
  W        Temperature warming
  X        Mixed data values

------------------------------------------------------------------
Table B5
T2 (T1 = E Satellite Imagery)
  C        Cloud top temperature
  F        Fog
  I        Infrared Range
  S        Surface temperature
  V        Visible Range
  W        Water vapor
  Y        User specified
  Z        Unspecified

------------------------------------------------------------------
Table C1

Land observation locations A1A2 use the same country codes as seen 
previously for the identical LL in part 5 of our main document.  
Please refer to that section.

Other Geographical Area Designators:

AA   Antarctic                       MP   Central Mediterranean
AC   Arctic                          MQ   Western Mediterranean
AE   South-East Asia
AF   Africa                          NA   North America
AM   Central Africa                  NT   North Atlantic area
AO   West Africa
AP   Southern Africa                 OC   Oceana
AS   Asia                            OH   Sea of Okhotsk
AW   Near East           
AX   Arabian Sea area                PA   Pacific area
                                     PE   Persian area
BQ   Baltic Sea area                 PN   North Pacific area
                                     PQ   Western North Pacific
CA   Caribbean & Central America     PS   South Pacific area
                                     PW   Western Pacific area 
EA   East Africa                     PZ   Eastern Pacific area
EC   East China Sea area
EE   Eastern Europe                  SA   South America       
EM   Middle Europe                   SE   Southern Ocean area
EN   Northern Europe                 SJ   Sea of Japan area
EU   Europe                          SS   South China Sea area
EW   Western Europe                  ST   South Atlantic area

FE   Far East                        XE   Eastern hemisphere  
                                     XN   Northern hemisphere
GA   Gulf of Alaska area             XS   Southern hemisphere
GX   Gulf of Mexico area             XT   Tropical belt      
                                     XW   Western hemisphere
IO   Indian Ocean area               XX   For use when others
                                          are not appropriate   
ME   Eastern Mediterranean area
MM   Mediterranean area

----------------------------------------------------------------
Table C2

Geographical Designator A1 A2

1. The first letter A1 will denote the nature of the ship or 
automatic marine station:

For ocean weather stations:                     W
For mobile ships and other marine stations:     V

2. The second letter A2 will denote the area from which the 
reports contained in the bulletin originate:

Designator               Data Area
          A         Area between 30o N - 60o S, 035o W - 070o E
          B         Area between 90o N - 05o N, 070o E - 180o E
          C         Area between 05o N - 60o S, 120o W - 035o W
          D         Area between 90o N - 05o N, 180o W - 035o W
          E         Area between 05o N - 60o S, 070o E - 120o W
          F         Area between 90o N - 30o N, 035o W - 070o E
          J         Area between 60o S
          X         More than one area

-----------------------------------------------------------------
Table C3
Location Codes

(A1 when T1=D,G,O,P,or T, A2 when T1= I, J, or K

    A            0 - 90 W northern hemisphere
    B            90W - 180 northern hemisphere
    C            180 - 90E northern hemisphere
    D            90E - 0 northern hemisphere
    E            0 - 90W tropical belt
    F            90W - 180 tropical belt
    G            180 - 90E tropical belt
    H            90E - 0 tropical belt
    I            0 - 90W southern hemisphere
    J            90W - 180 southern hemisphere
    K            180 - 90E southern hemisphere
    L            90E - 0 southern hemisphere
    N            Northern hemisphere
    P            Area between 64.69N - 136.76W, 55.61N - 13.43W
                              64.69N - 156.76W, 55.61N - 33.43W
    S            Southern hemisphere
    T            45W - 180 northern hemisphere
    U            Area between 21.0N - 128.1W, 36.0N - 130.9W
                              21.1N - 113.0W, 36.2N - 110.5W
    V            Area between 30.3N - 83.7W, 51.0N - 68.9W
                              19.8N - 64.5W, 33.3N - 47.1W
    X            Global Area (area not definable)

When T1=H:
    A                 0 - 180 E northern hemisphere        [21]
    B                 180 W - 0 northern hemisphere        [22]
    C                 0 - 180 E southern hemisphere        [23]
    D                 180 W - 0 southern hemisphere        [24]
    E                 0 - 355 E northern hemisphere        [25]
    F                 0 - 355 E southern hemisphere        [26]
    G                 Regional use
    H                 Not Assigned
    I                 30 W - 60 E northern hemisphere      [37]
    J                 60 W - 150 E northern hemisphere     [38]
    K                 150 E - 120 W northern hemisphere    [39]
    L                 120 W - 30 W northern hemisphere     [40]
    M                 30 W - 60 E southern hemisphere      [41]
    N                 60 W - 150 E southern hemisphere     [42]
    O                 150 E - 120 W southern hemisphere    [43]
    P                 120 W - 30 W southern hemisphere     [44]
    Q-S               Not Assigned
    T                 0 - 180 E northern hemisphere        [61]
    U                 180 W - 0 northern hemisphere        [62]
    V                 0 - 180 E southern hemisphere        [63]
    W                 180 W - 0 southern hemisphere        [64]
    X                 Regional use
    Y-Z               Not Assigned

----------------------------------------------------------------
Table C4
Time Designators
A2 when T1 = D,G,H,O, P, or T

A            Analysis (00 hour)
B             6 hours forecast
C            12 hours forecast
D            18 hours forecast
E            24 hours forecast
F            30 hours forecast
G            36 hours forecast
H            42 hours forecast
I            48 hours forecast
J            60 hours forecast
K            72 hours forecast
L            84 hours forecast
M            96 hours forecast
N           108 hours forecast
O           120 hours forecast
P           132 hours forecast 
Q           144 hours forecast
R           156 hours forecast
S           168 hours forecast
T            10 days forecast
U            15 days forecast
V            30 days forecast
W...Z        Not assigned

------------------------------------------------------------------
Table C5
Reference Time Designators
(A2 when T1 = Q, X, or Y)

A             Analysis (00 hour)
B             3 hours forecast
C             6 hours forecast
D             9 hours forecast
E            12 hours forecast
F            15 hours forecast
G            18 hours forecast
H            21 hours forecast
I            24 hours forecast
J            27 hours forecast
K            30 hours forecast
L            33 hours forecast
M            36 hours forecast
N            39 hours forecast
O            42 hours forecast
P            45 hours forecast
Q            48 hours forecast
R            54 hours forecast [48+6]
S            66 hours [+12]
T            78 hours  
U            90 hours    
V           102 hours
W           114 hours
X           126 hours
Y           138 hours
Z           150 hours

------------------------------------------------------------------
Table C6
Data Type Designator
(A1 = I, or J) 

1. The designators specified in this table should be used to the 
greatest extent possible to indicate the type of data contained 
within the body of the BUFR bulletin.

2. Where more than one data type is contained in the bulletin, the 
designators for only one of the data types should be used.

3. When the table does not contain a suitable designator for the 
data type, an alphabetic designator which is not assigned in the 
table should be introduced and the WMO Secretariat notified.

T1   = I   Observational Data
and

T2   = S   Surface
Designator     Data type    

  A            Land based hourly reports           
  C            Climatic reports                    
  I            Land intermediate synoptic reports
  M            Land based Main synoptic reports
  N            Land based asynoptic intermediate reports
  P            Land based hourly specials
  S            Floating platforms (ship, buoy, etc.)
  R            Hydrologic reports
  X            Other surface data
  Z            Bulletins with mixed data type reports

T1   = I   Observational Data
and

T2   = U   Upper Air

Designator     Data type

  A          Single level aircraft reports
  B          Single level balloon reports
  C          Single level satellite derived reports
  D          Dropsonde/dropwindsondes
  M          Model derived sondes
  N          Rocketsondes
  P          Profilers
  R          Radiance data
  S          Radiosondes/pibal reports
  T          Satellite derived sondes
  X          Other upper air reports
  Z          Mixed upper air reports

T2   = T   TEXT

Designator     Data type

  A        Administrative message
  B        Service message
  R        Request for data (inclusive of type)
  X        Other text messages of information
  Z        Mixed text types

T1   = I   Observational Data
and

T2   = P   PICTORIAL

Designator     Data type

  I        Satellite imagery data
  R        Radar reports
  X        Not defined
  Z        Mixed data types

T1   = I or J   Observational Data / Forecast Products)
and

T2   = O   Oceanographic/Limnographic

Designator     Data type

  I        Sea ice
  S        Sea surface and below soundings
  T        Sea surface temperature
  W        Sea surface waves
  X        Other sea environmental
  Z        Mixed collection of oceanographic types

T1   = J   (Forecast Products)
and

T2   = S   Surface/Sea Level

Designator     Data type

  A        Surface area forecast (e.g. airway)
  M        Surface forecast (e.g. MOS)
  P        Forecast amendments (e.g. airways)
  R        Hydrologic forecast
  S        Forecast amendments (TAF)
  T        Aerodrome forecast (TAF)
  X        Other surface forecasts
  Z        Mixed collection of forecast types

T1   = J   (Forecast Products)
and

T2   = U   Upper Air

Designator     Data type

  A        Forecast at single levels
  S        Forecast soundings
  X        Other upper air forecasts
  Z        Mixed collection of forecast types

T1   = J   (Forecast Products)
and

T2   = T   TEXT WARNINGS/Notices

Designator     Data type

  E        Tsunami
  H        Hurricane, typhoon, tropical storm warning
  S        Severe weather, SIGMET
  T        Tornado warning
  X        Other warnings
  Z        Mixed collection of warnings

-----------------------------------------------------------------
Table C7
Data Type Designator A1 for Values of T2 = S, U, O, F, and V
( when T1   =   K - CREX )
CBS XI, Cairo 1996

1. The designators specified in this table should be used to the 
greatest extent possible to indicate the CREX type of 
observational data contained within the body of the bulletin.

2. When the table does not contain a suitable designator for the 
observational data type, an alphabetic designator which is not 
assigned in the table should be introduced and the WMO Secretariat 
notified.

3. In the event no standard format has been established for a 
particular data type, and there is a recommended format, that 
format is given in square brackets under the column labeled Code 
Form (e.g. [ASCII]). This is a character code - International 
Alphabet No.5 (Attachment II-2) will be used.

T2 = S Surface
A1

Designator     Data type                       Code Form (CREX)
A            Land based hourly reports                  [ASCII]
C            Climatic reports                           [ASCII]
I            Land intermediate synoptic reports         [ASCII]
M            Land based main synoptic reports           [ASCII]
N            Asynoptic intermediate reports             [ASCII]
P            Land based hourly specials                 [ASCII]
S            Floating platforms (ship, buoy, etc.)      [ASCII]
R            Hydrologic reports                         [ASCII]
X            Other surface reports                      [ASCII]
Z            CREX bulletins with mixed data type rpts   [ASCII]

T2 = U Upper Air 
A1

Designator     Data type                       Code Form (CREX)

A          Single Level aircraft reports                [ASCII]
B          Single level balloon reports                 [ASCII]
C          Single level satellite derived reports       [ASCII]
D          Dropsondes/dropwindsondes                    [ASCII]
L          Ozone data                                   [ASCII]
N          Rocketsondes                                 [ASCII]
P          Profiler                                     [ASCII]
R          Radiance data                                [ASCII]
S          Radiosonde/pibal                             [ASCII]
T          Satellite derived sondes                     [ASCII]
X          Other upper air reports                      [ASCII]
Z          Mixed upper air data type reports            [ASCII]

T2 = O Oceanographic/Liminographic
A1

Designator     Data type                       Code Form (CREX)

I        Sea Ice                                        [ASCII]
S        Sea surface and below sounding                 [ASCII]
T        Sea surface temperature                        [ASCII]
W        Sea surface waves                              [ASCII]
X        Other sea environmental                        [ASCII]
Z        Mixed collection of oceanographic types        [ASCII]

T2 = F   FORECASTS - Surface/Sea Level 
A1

Designator          Data type                  Code Form (CREX)
A       Surface area forecast (e.g. airways)            [ASCII]
M       Surface forecasts (e.g. MOS)                    [ASCII]
P       Forecast amendments (airways)                   [ASCII]
R       Hydrologic forecasts                            [ASCII]
S       Forecast amendments (TAF)                       [ASCII]
T       Aerodrome forecasts (TAF)                       [ASCII]
X       Other surface forecasts                         [ASCII]
Z       Mixed collection of forecasts                   [ASCII]

T2 = V   FORECASTS - Upper Air 
A1

Designator          Data type                  Code Form (CREX)

A       Single level                                    [ASCII]
S       Soundings                                       [ASCII]
X       Other upper air forecasts                       [ASCII]
Z       Mixed collection of forecasts                   [ASCII]

Note: The allocation of abbreviated headings for CREX messages is 
pending the formal approval of the code CREX.

-----------------------------------------------------------------
Table D1
Level Designators
(ii when T1=O)

     98               Surface 
     96               2.5
     94               5.0
     92               7.5
     90               12.5
     88               17.5
     86               25.0
     84               32.5
     82               40.0
     80               50.0
     78               62.5
     76               75.0
     74               100
     72               125
     70               150
     68               200
     66               300
     64               400
     62               500
     60               600
     58               700
     56               800
     54               900
     52               1000
     50               1100
     48               1200
     46               1300
     44               1400
     42               1500
     40               1750
     38               2000
     36               2500
     34               3000
     32               4000
     30               5000
     01               Primary layer depth

----------------------------------------------------------------
Table D2
Level Designators
(ii when T1= D,G,H,P,Q,X or Y)

     99               1000 hPa
     98               Air properties for the earth's surface 
     97               Level of the tropopause
     96               Level of maximum wind
     95               950 hPa
     94               Level of 0oC isotherm
     93               Not assigned - 975 hPa(U.S. use)
     92               925 hPa
     91               Not assigned - 875 hPa(U.S. use)
     90               900 hPa
     89               Any parameter reduced/sea level (MSLP)
     88               Ground/water properties for the earth's
                      surface (i.e. snow cover, wave & swell)
     87               1000-500 hPa thickness
     86               Boundary Layer
     85-01            Hundreds and tens digits of the hectopascal
                      level (e.g. 70 = 700 hPa;03 = 030 hPa)
                      TO INCLUDE:
                         81 = 810 hPa = 6000ft FL
82 = 825 hPa(U.S. use)
                         77 = 775 hPa(U.S. use)
                         73 = 730 hPa = 9000ft FL 
                         72 = 725 hPa(U.S. use)
                         67 = 675 hPa(U.S. use)   
                         65 = 650 hPa = 12000ft FL
                         62 = 625 hPa(U.S. use)  
     00               Entire Atmosphere (e.g. precipitable water)

US Tables
---------

Table B6
Data Type designator T2
( when T1   =   Y or Z )

U.S. Table for National GRIB Products
U.S. National Practice

1. The designator specified in this table should be used to the 
greatest extent possible to indicate the data types of the data 
contained within the text of the bulletin.

2. Where the data type does not correspond exactly with the 
designator, the designator for the most approximate type of the 
data may be used.

3. The NWS will assign designators to this table in place of the 
unassigned designators when needed.

Designator                   Data Type

A               Cloud parameters (ice, water)
B               Vertical Wind Shear
C               Vorticity
D               Probability Values (Thunderstorm, Precip types,
                 Cloud types)
E               Precipitation parameters (Precip. water, 
                 convective Precip.)
F               Long wave radiation
G               Temperature Values (Maximum, Minimum, Dew Point)
H               Height (geopotential)
I               unassigned
J               unassigned
K               Ocean wave properties (Period, Direction)
L               unassigned
M               unassigned
N               unassigned
O               Vertical velocity/Surface Lifted index
P               Pressure
Q               Stability Index
R               Relative humidity
S               Snow properties
T               Temperature
U               Wind components (U V)
V               unassigned
W               Cape/Cin/Helicity
X-Z             unassigned

------------------------------------------------------------------
Table C8
Geographical area designator A1
(when T1   =   H)
U.S. National Table derived from WMO Table C3

1. The designator specified in this table should be used to the 
greatest extent possible to indicate the geographical area of the 
data contained within the text of the bulletin.

2. Where the geographical area of the data does not correspond 
exactly with the designator, the designator for the area most 
approximating that of the data may be used.

3. When the table does not contain a suitable designator for the 
geographical area, an alphabetic designator which is not assigned 
in the table will be introduced.

   Designator                   Geographical Area

      A                 0 - 180 E northern hemisphere        [21]
      B                 180 W - 0 northern hemisphere        [22]
      C                 0 - 180 E southern hemisphere        [23]
      D                 180 W - 0 southern hemisphere        [24]
      E                 0 - 355 E northern hemisphere        [25]
      F                 0 - 355 E southern hemisphere        [26]
      G                 Regional use
      H                 Not Assigned
      I                 30 W - 60 E northern hemisphere      [37]
      J                 60 W - 150 E northern hemisphere     [38]
      K                 150 E - 120 W northern hemisphere    [39]
      L                 120 W - 30 W northern hemisphere     [40]
      M                 30 W - 60 E southern hemisphere      [41]
      N                 60 W - 150 E southern hemisphere     [42]
      O                 150 E - 120 W southern hemisphere    [43]
      P                 120 W - 30 W southern hemisphere     [44]
      Q-S               Not Assigned
      T                 0 - 180 E northern hemisphere        [61]
      U                 180 W - 0 northern hemisphere        [62]
      V                 0 - 180 E southern hemisphere        [63]
      W                 180 W - 0 southern hemisphere        [64]
      X                 Regional use
      Y-Z               Not Assigned

Geographical area designator A1
( when T1   =   Y or Z )

Designator              Geographical Area                NCEP GRID No.

      A                 northern hemisphere                 [201]
      B                 unassigned
      C                 unassigned
      D                 unassigned
      E                 unassigned
      F                 unassigned
      G                 unassigned
      H                 National CONUS w/ Double Resolution  [213]
      I                 National CONUS                       [202]
      J                 National Alaska                      [203]
      K                 National Hawaii                      [204]
      L                 National Puerto Rico                 [205]
      M                 Regional MARD                        [206]
      N                 Regional Alaska                      [207]
      O                 Regional Hawaii                      [208]
      P                 Regional Puerto Rico                 [210]
      Q                 Regional CONUS                       [211]
      R                 Regional CONUS w/ Double Resolution  [212]
      S                 Regional MARD w/ Double Resolution   [209]
      T                 Regional Alaska w/ Double Resolution [214]
      U                 Regional CONUS                       [215]
      V                 Regional Alaska                      [216]
      W-Z               unassigned

------------------------------------------------------------------
Table C9
Geographical-Tile Number designator T2 A1
( when T1   =   Z   and the CCCC   =   KWBZ)

( A DRAFT U.S. National Practice Table )

Instructions for the proper application of the Geographical "TILE" 
number designator - A two character field of the heading.

1. The designator specified in this table should be used to the 
greatest extent possible to indicate the geographical high 
resolution grid tile number of the data contained within the 
geographical area as specified by the grid squares defined by the 
producing center of the GRIB bulletin.

2. Where the geographical tile number for the area of the data 
does not correspond exactly with the designator, the number 
designator for the area most approximating that area of the data 
may be used. The exact area of coverage will be available within 
the GRIB Product Definition Section (PDS) of the bulletin.

Designator           Geographical Area Tile Number        NCEP Model

AA - AW              01 - 24 CONUS 20 km tiles            meso-Eta
AY - AZ              unassigned
BA - BW              01 - 24 CONUS 20 km tiles            RUC
BY - BZ              unassigned
CA - CW              unassigned
CY - CZ              unassigned
DA - DZ              unassigned
EA - EZ              unassigned
FA - FZ              unassigned
GA - GZ              unassigned
HA - KR              01 - 96 CONUS 10 km tiles            meso-Eta
KS - KZ              01 - 08 Alaska 20 km tiles           RUC
LA - OR              01 - 96 CONUS 10 km tiles            RUC
OS - OZ              01 - 08 Hawaii 20 km tiles           RUC
PA - QZ              unassigned
RA - RF              01 - 06 CONUS 40 km tiles            meso-Eta
RG - RL              01 - 06 CONUS 40 km tiles            RUC
RM - RR              01 - 06 Alaska 40 km tiles           meso-Eta
RS - RX              01 - 06 Alaska 40 km tiles           RUC
RY - RZ              unassigned
SA - SF              01 - 06 Hawaii 40 km tiles           meso-Eta
SG - SL              01 - 06 Hawaii 40 km tiles           RUC
SM - ZZ              unassigned

-----------------------------------------------------------------
Table C10
Reference Time designator A2
(when T1   =   Y or Z)

1. The designator specified in this table should be used to the 
greatest extent possible to indicate the reference time of data 
contained within the text of the bulletin.

2. When the table does not contain a suitable designator for the 
reference time, use "Z" and obtain the forecast hour from the GRIB 
Product Definition Section.

Designator   Data Type          Designator   Data Type 

A       Analysis (00 hour)       N       18 hours forecast
B       1 hour forecast          O       24 hours forecast
C       2 hours forecast         P       30 hours forecast
D       3 hours forecast         Q       36 hours forecast
E       4 hours forecast         R       42 hours forecast
F       5 hours forecast         S       48 hours forecast (2 days)
G       6 hours forecast         T       60 hours forecast
H       7 hours forecast         U       72 hours forecast (3 days)
I       8 hours forecast         V       84 hours forecast
J       9 hours forecast         W       96 hours forecast (4 days)
K      10 hours forecast         X      108 hours forecast 
L      11 hours forecast         Y      120 hours forecast (5 days)
M      12 hours forecast         Z       Time contained in PD Block
                                          of GRIB code

---------------------------------------------------------------------
Table D3

Level designator ii
(when T1 = H, X, Y, or Z) 

(U.S. National Practice definitions included)

Instructions for the proper application of level (elevations above 
the earth's surface) designator.

1. The designator specified in this table should be used to the 
greatest extent possible to indicate the level of the data 
contained within the text of the bulletin.

2. When data at more than one level are contained in the text, the 
designator for only one of the levels should be used.

3. When the table does not contain a suitable designator for the 
level, a designator which is not assigned in the table should be 
used.

The U.S. Practice uses 25 mb increments 1000-100 mb and are 
included below.

       ii

   Designator       Level

     00               Entire Atmosphere (e.g. precipitable water)
     99               1000 hPa
     98               Air properties for the earth's surface 
     97               Level of the tropopause
     96               Level of maximum wind
     95               950 hPa
     94               Level of 0oC isotherm
     93               975 hPa
     92               925 hPa
     91               875 hPa
     90               900 hPa
     89               Any parameter reduced/sea level (MSLP)
     88               Ground/water properties for the earth's
                      surface (i.e. snow cover, wave & swell)
     87               1000-500 hPa thickness
     86               Boundary Layer
     74               Cloud top level
     85-01            Hundreds and tens digits of the hectopascal
                      level(e.g. 70=700 hPa;03=030 hPa)
                      TO INCLUDE:
                         81 = 810 hPa = 6000ft FL
                         82 = 825 hPa
                         84 = 875 hPa
                         77 = 775 hPa
                         73 = 730 hPa = 9000ft FL 
                         72 = 725 hPa
                         67 = 675 hPa   
                         65 = 650 hPa = 12000ft FL
                         62 = 625 hPa
                         50 = 510 hPa = 18000ft FL (U.S. National 
Practice uses 500 mb level)
                         11 = First 30 mb average thickness [from 
surface]
                         12 = Second 30 mb average thickness 
                         13 = Third 30 mb average thickness 
                         14 = Forth 30 mb average thickness 
                         45 = Fifth 30 mb average thickness
                         16 = Sixth 30 mb average thickness 

Note: The 810, 730, and 650 hPa levels are not being used as 
pressure levels, they are being used as geometric heights.

Appendix #2: What BBB Codes Mean
================================

GUIDELINES on the USE of the INDICATOR BBB

T1T2A1A2ii   CCCC   YYGGgg   (BBB)

This line, which is preceded by "format effectors" [ cr ] [ cr ] [ 
lf ], constitutes the complete WMO abbreviated heading line, which 
can contain the optional BBB group, indicated by the open and 
closed parenthesis ( ).

General Instructions

The WMO abbreviated heading line, including each unique YYGGgg 
(date time group), shall be used only once a month, due to the day 
of the month being part of the heading. The indicator BBB shall 
only be added when a WMO abbreviated heading has already been used 
for transmission of an initial bulletin. It indicates that the 
contents to be a delayed, corrected or amended bulletin. The 
indicator BBB can also be used for segmentation as described below 
in paragraph 5.

The indicator BBB shall only be included in the WMO abbreviated 
headings of delayed (retard), corrected, or amended bulletins by 
those centres which are responsible for preparing, or compiling 
the bulletins concerned, or for communication transmission reasons 
by any system as a segment sequence indicator when bulletins are 
segmented to control bulletin size.

Once the initial bulletin has been transmitted, the centre 
responsible for preparing or compiling the original bulletin uses 
the indicator BBB to transmit delayed or corrected reports or to 
amend information for the same abbreviated heading containing the 
same YYGGgg. 

A centre shall not construct an abbreviated heading with the 
indicator BBB for delayed, corrected, amended, bulletins having a 
size larger than the limit defined in TABLE A as it would cause a 
communications system to segment it before transmission.

The Bulletin Segment Heading is a special form of the WMO 
abbreviated heading where the indicator BBB takes the form of Pxx. 
The bulletin segment heading replaces the normal WMO abbreviated 
heading when bulletins are larger than size limit defined in WMO 
Table A. The bulletin segment heading shall take the place of the 
WMO abbreviated heading for electronic transmission purposes. The 
bulletin segment heading is a repeating heading, with a unique Pxx 
group for each segment. The original WMO bulletin shall be re-
constructed from these segments before use.

The bulletin segment heading cannot be used in place of a standard 
WMO abbreviated heading of a bulletin if any of the other 
indicator BBB options are present. This normally will not be a 
problem as a delayed, corrected, or amended bulletin with the 
indicator BBB should be smaller then the initial message. However, 
the U.S. has established a National practice to support the 
transmission of plain text bulletins containing an abbreviated 
heading with a BBB group which are too large for transmission. 

BBB Forms
The four forms of the BBB indicator group are: 

RRx - Delayed (Retard) 
CCx - Correction 
AAx - Amendment 
Pxx - Segment number 
Each form precludes the use of the others in the same bulletin. 
The RRx, CCx, and AAx forms are attributes of the content of the 
bulletin, and the Pxx is an attribute of the segment number not 
the content. Each form is described separately below.

RRx Indicator Group - Delayed Routine Meteorological Reports 
[retard]

This indicator group has the form RRx; where: x = A through X. It 
is used to transmit a collection of one or more weather reports 
which are normally contained in the initial bulletin but which 
were received after the initial bulletin has been transmitted. The 
value of x = A is for the first bulletin containing additional 
reports; a value of x = B for a second bulletin containing 
additional reports, if necessary, and, so on up to and including x 
= X. For x = Y it represents a loss of the record of the sequence 
by the issuing center. For x = Z it represents the compiled 
bulletin is over 24 hours after the time of observation.

CCx Indicator Group -Corrections to Previously Transmitted Reports 
This indicator group has the form: CCx; where x = A through X. It 
is used to transmit a bulletin containing corrections to reports 
that have already been included in a bulletin previously 
transmitted. The value of x = A is for the first bulletin 
containing corrected reports; a value of x = B for a second 
bulletin containing additional corrected reports, if necessary, 
and, so on up to and including x = X. For x = Y it represents a 
loss of the record of the sequence by the issuing center. For x = 
Z it represents the compiled bulletin is over 24 hours after the 
time of observation.

AAx Indicator Group - Amendments to Processed Information 
This indicator group has the form AAx; where x = A through X. It 
is used to transmit a bulletin containing amendments to processed 
information in a bulletin which has previously been sent. The 
value of x = A is for the first bulletin containing information 
amending the basic (initial) bulletin; a value of x = B for a 
second bulletin containing information amending the basic 
(initial) bulletin, if necessary, and so on up to and including x 
= X. For x = Y it represents a loss of the record of the sequence 
by the issuing center. For x = Z it represents the compiled 
bulletin is over 24 hours after the time of observation.

Pxx Indicator Group - Segmentation of a Large Bulletin

When a bulletin exceeds the length limit defined in Table A, it 
shall be segmented for communications purposes using a bulletin 
segment heading line utilizing the Pxx Indicator Group. There are 
two different structures possible for segments. Segmented 
alphanumeric products have a supplementary identification line 
which repeats information in addition to the bulletin segment 
heading line in each segment. Segmented binary products do not 
repeat the supplementary identification line information in a 
second line for each subsequent segment. Only the bulletin segment 
heading line is repeated.

Defining:

Pxx = values of xx = AA through YZ and ZA through ZZ

The following principles shall apply when segmenting alphanumeric 
bulletins for transmission:

The first bulletin segment heading will have sequence indicator xx 
= AA, the second AB and so on up to the last bulletin segment 
heading which shall have xx = Zx.

The Z is a LAST SEGMENT FLAG and is placed in the first x position 
of the Pxx group of the last segment of the set of bulletin 
segments with the second x the sequence letter which would have 
normally been used if this was not the last segment.

This special PZx group is required to inform the receiving center 
that no more bulletin segments exist for this product.

And; 
Any original code form or product identification indicator shall 
be included in each bulletin segment heading and is called a 
supplementary identification line.

Except for the last segment, segment lengths shall be as long as 
possible, within approved bulletin length limits [Table A] and 
formatting constraints.

Segmented bulletin breaks shall immediately follow end-of-report 
indicator signals ( = signs ) when or where available in close 
proximity to the size limit. When end-of report indicators can't 
be used, segmented plain text bulletins will be broken on an end-
of-line function or on a space if the end-of-line function can not 
be found in close proximity to the size limit.

All WMO Regional Telecommunication Hubs on the Global 
Telecommunication System should relay bulletin segments as 
received on the Main Trunk Network.

Upon receipt all plain text bulletin segments the receiving end 
shall re-built the original bulletin prior to use, as the 
segmentation procedure is for transmission purposes only.

Bulletin segments must be processed to re-build the original 
bulletin to obtain a complete plain text product.

U.S. National Practice

If it is necessary to segment a bulletin which exceeds the limits 
established by WMO and the bulletin already utilizes a bulletin 
attribute (BBB), the following procedures will be used. A bulletin 
segmentation heading including the appropriate Pxx indicator group 
will be used; and the original bulletin attribute (BBB) will be 
included as a separate line followed immediately by the line 
function carriage return, carriage return, line feed in the first 
segment only. (see examples below) 

Binary Bulletins

The following principles shall apply when segmenting binary 
bulletins (i.e. GRIB, BUFR, and T4 FAX bulletins):

Bulletin segment lengths shall be as long as possible, as allowed 
by approved bulletin length limits (except for the last segment) 
RTHs should relay bulletin segments as received 
An example of the segmentation of a T4 FAX WMO bulletin that has 
been received too large according to Table A for onward 
transmission without segmentation: 
Example:

FIRST BULLETIN SEGMENT 

     PGEE25 KWBC 181200 PAA
     DFAX 1064  bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
     bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
     bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
     bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
     bbbbbbbbbbbbbbbbbbbbbbb .....etc...

[ until 15000 octets have been reached ]

SECOND BULLETIN SEGMENT 

     PGEE25 KWBC 181200 PAB
     bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
     bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
     bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
     bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
     bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
     bbbbbbbbbbbbbbbbbbbbbbbb .....etc...

[ until 15000 octets have been reached ]

THIRD BULLETIN SEGMENT 

     PGEE25 KWBC 181200 PAC
     bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
     bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
     bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
     bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
     bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
     bbbbbbbbbbbbbbbbbbbbbbbb .....etc...

[ until 15000 octets have been reached ]

FOURTH and LAST BULLETIN SEGMENT

     PGEE25 KWBC 181200 PZD
     bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
     bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
     bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
     bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
     bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
     bbbbbbbbbbbbbbbbbbbbbbbb .....etc...

[ until something less than 15000 octets have been reached ]

Warning !
Bulletin segments must be processed to re-build the original 
bulletin from it's segment parts to be able to obtain the complete 
binary bulletin prior to further use.

All binary bulletins greater than 15,000 bytes will be segmented 
unless prior mutual agreement between adjacent centers has 
established otherwise. The segments will be based upon size only 
and no consideration will be given to where the break occurs. 
Bulletin segments will have no additional information added beyond 
the bulletin segment heading line itself, containing the BBB group 
of Pxx to accomplish the segmentation process.

Additional comments on the use of the BBB groups.

An RTH on the GTS should ensure the relay of any bulletins 
received in accordance with its routing directories even if the 
bulletins are in fact bulletin segment heading lines and have not 
been received in the correct sequence. All the bulletin segments 
containing the indicator Pxx shall be relayed to enable the end 
user to reconstruct and use the original bulletin.

In case of incomplete or incorrect reception, the use of the 
addressed message for request/reply may be required for recovering 
incomplete or incorrect bulletin(s). The request for a bulletin 
segment may be acceptable, or the request for the repeated 
transmission of the entire set of information (i.e. the whole 
sequence of bulletin segments) may be necessary, in which case the 
indicator Pxx would not be used in the request.

Appendix #3: The METAR Code
===========================

   METAR was adopted in 1996 as the world standard, replacing the 
Airways Code used in the US.  More recently, such US broadcasts as 
ATIS and VOLMET have gone to the METAR form for reporting 
observations.  The biggest change is the use of Celsius for 
temperature in the US.  Exceptions to the international standard 
allow for the use of feet, inches, and statute miles for other 
observations.

   American observations will never have QNH (surface pressure in 
hectopascals or millibars), while European and other foreign ones 
usually do, and this is one way to tell them in voice weather 
traffic such as VOLMET.

   Although not used in the US, "Ceiling And Visibility OK" 
(CAVOK) replaces visibility, weather and clouds if:
 1) visibility greater than or equal to 10 kilometers;
 2) no clouds below 1500 meters or below the highest minimum 
sector altitude, whichever is greater and no CB; and
 3) no precipitation, TS, DS, SS, MIFG, DRDU, DRSA, or DRSN. 

METAR Format (FM-15) 
Surface Meteorological Airways Format 

Syntax: 
METAR CCCC TIME AUTO WIND VISIBILITY WEATHER CLOUDS TEMP/DEW 
ALTIMETER REMARKS 

METAR 
This defines the product type.
METAR		regularly reported observation (such as an hourly)
SPECI		special observation
TESTM		non-commissioned ASOS report

CCCC 
CCCC is the 4 letter ICAO ID uniquely defining the reporting 
station.

CONUS sites begin with 'K', Alaskan sites begin with 'PA', 
Hawaiian sites begin with 'PH', Canadian sites begin with 'C', 
Mexican sites begin with 'MM'

TIME 
The full universal time (UTC) that the observation was taken.  The 
format is: 

ddhhmmZ.   

dd is the day of the month, hh is the hour, mm is the minute. 
Z refers to Zulu time.

AUTO
This is an optional grouping used in the US to specify a station 
as being automated.

COR
This is an optional grouping used in the US to specify an 
observation as being corrected.

WIND 
The wind group 

dddssKT or dddssGggKT 

The value ddd is the wind direction in degrees.  The value ss is 
the wind speed.  The units are defined by the string "KT" which is 
knots. Some reports may have "MPS" for meters per second. If wind 
gusts are reported, they are specified with the group "Ggg". 

VISIBILITY 
The visibility group

vvSM or vvKM 

This specifies the visibility is either statue miles "SM" (US), or 
kilometers "KM".  The visibility can be partial values such as "1 
1/2SM" or "3/16SM". Optionally a 4-digit minimum visibility in 
meters and as required, lowest value with direction.

RR/xxxx xxxx
Runway Visual Range (optional)
R; 2-digit runway designator; Left, Center, or Right as
needed; "/"; Minus or Plus (as needed); in U.S, 4-digit value; 
FeeT in U.S. <usually meters elsewhere>; as needed, 4-digit value; 
Variability; 4-digit value (and tendency Down, Up or No change)

WEATHER 
The weather group 

iiddppooxx 

ii is intensity group ii Description 
-  light  
 moderate  
+  heavy  
VC  in the vicinity  

dd is the descriptor group dd Description 
MI  shallow  
PR  partial  
BC  patches  
DR  low drifting  
BL  blowing  
SH  shower  
TS  thunderstorm  
FZ  freezing  

pp is the precipitation group pp Description 
DZ  drizzle  
RA  rain  
SN  snow  
SG  snow grains  
IC  ice crystals  
PE  ice pellets  
GR  hail  
GS  small hail/snow pellets  
UP  unknown  

oo is the obscuration group oo Description 
BR  mist  
FG  fog  
FU  smoke  
VA  volcanic ash  
DU  dust  
SA  sand  
HZ  haze  
PY  spray  

xx is the misc group xx Description 
PO  dust whirls  
SQ  squalls  
FC  funnel cloud/tornado/waterspout  
SS  duststorm  

CLOUDS 
The cloud levels 

ccchhhtt 

ccc is the coverage 
CLR or SKC = clear 
FEW = 1/8 coverage 
SCT = 2,3,4/8 coverage 
BKN = 5,6,7/8 coverage 
OVC = overcast 
VV = vertical visibility for obscuration 

hhh is the height of base in 30m or 100ft increments. ie 30 = 3000 
feet 

tt is an optional type
CU = cumulus
CB = cumulonimbus
TCU = towering cumulus 
CI = cirrus 

CAVOK = clear skies, unlimited visibility

CAVOK is a widely used national practice, though not in the US.
When placed in this group, it means Clouds And Visibility OK.
Often NOSIG (No Siginficant features/changes)is placed in the
comment field to indicate that this condition will not change for
two hours.

In automated METAR reports only, CLeaR means "clear below 12,000 
feet"

TEMP/DEW 
is the temperature and dewpoint in Celsius 

TT/DD 

negative values are preceded with a M (M03 = -3) 

ALTIMETER 
is the altimeter setting 

Qpppp = altimeter in whole mb 

Apppp = altimeter in .01 in Hg 

REMARKS 
The remark section: 

RMK xxxx xxxx xxxx...
Remark		Description 
AO1			AMOS station  
AO2			ASOS station  
OBS TAKEN +xx minute offset for observation time 
SLPppp		Sea level pressure in .1 mb (142 = 1014.2 mb)  
WEA:www		Additional present weather information 
Tttttdddd		Current temperature/dewpoint in .1C
			first digit 1 for negative  
1xxxx			6 hour max temp in .1C, first digit 1 for 
negative  
2nnnn			6 hour min temp in .1C, first digit 1 for 
negative  
4/sss			Snow coverage in inches 
4xxxxnnnn		24 hour max/min temps in .1C, first digit 1 for 
negative  
5tppp			Pressure tendency in .1 mb for 3 hours, t is the 
trend 
6pppp			6 hour precipitation in .01 inches  
7pppp			24 hour precipitation in .01 inches  
8/lmh			Cloud type for low, medium, high  
933sss		New snow coverage, water equivalent  
98mmm			Equivalent sunshine for day in minutes  
CITY tt		City temperature  
PCPN pppp 
Ppppp			1 hour precipitation  
PK WND sss/nn	Peak wind, sss is speed, nn is the time  
PRESFR		Pressure falling rapidly  
PRESRR		Pressure rising rapidly  
SNOINCR xxx	Snow increasing rapidly,
			where xxx is amount of snow in last hour
TSNO Automated station has no thunderstorm detector (US) 
WSHFT nn		Wind shift at time nn  

Appendix #4: SYNOP Code
=======================

SYNOP Data Format (FM-12) 
Surface Synoptic Observations 

   SYNOP code is the WMO standard method for transmitting surface 
weather information. It is universal in that separate optional 
formats exist for different units of measurement.  The entire 
content, except for some plain-text ICE observations, is numeric, 
and that the format never varies beyond basic standard departures 
authorized for individual countries.

   SYNOP is not as easy to read as METAR, but it is easier for a 
computer to encode and decode.  Many programs exist to do just 
that.  Unfortunately, SYNOP codes change frequently, keeping 
computer programmers on their toes.

   The official reference for any surface observer in the United 
States is the Federal Meteorological Handbook No. 1, published 
jointly by the US Departments of Commerce (NWS), Transportation 
(FAA), and Defense (AWS/Navy). The complete synoptic code is 
described in the Federal Meteorological Handbook No. 2 (same 
publishers as above).

   The coded report is given in six groups of data, or sections. 
Sections 0 and 1 are not identified by any special identifying 
groups, but Sections 2, 3, and 5 are recognizable by the 222, 333, 
or 555 included as part of the message (Section 4 is not used in 
the US). Surface marine data (from buoys which report hourly and 
ships-of-opportunity and weather ships, which report every 6 
hours) are found in section 2, which contains reporting formats 
peculiar to the SHIP code.

   Several forms of the observation were changed in the late 1990s 
and are not reflected in most online decoders. These include the 
10 m and 20 m wind speed estimates (11 and 22 groups), time and 
values of maximum winds (3 & 4 groups in section 5), and 10-minute 
average winds, beginning at the time of observation and working 
backwards in time (the last 6 groups of section 5 in the CMAN 
code).

000 Group - Identification and Location
111 Group - Land Observations
222 Group - Sea Surface Observations
333 Group - Climatological Data
444 Group - Clouds below a mountain station, not used in US
555 Group - National Practice Observations

Groups 0 and 1 have no beginning designators, but the others, when 
present will be 222, 333, and 555.

Not all groups need occur in all SYNOP.  Land stations will 
obviously not need group 2.

Syntax;

IIiii or IIIII YYGGi 99LLL QLLLL
iihVV Nddff 00fff 1sTTT 2sTTT 3PPPP 4PPPP 5appp 6RRRt 7wwWW 8NCCC 
9GGgg
222Dv 0sTTT 1PPHH 2PPHH 3dddd 4PPHH 5PPHH 6IEER 70HHH 8aTTT
333 0.... 1sTTT 2sTTT 3Ejjj 4Esss 5jjjj jjjjj 6RRRt 7RRRR 8Nchh 
9SSss 
444 Not usually used
555 National practice - varies

Section 0: Station & Date/time information
------------------------------------------

IIiii or IIIII YYGGi 99LLL QLLLL

For land stations :

     AAXX  YYGGiw  IIiii

   For land stations, the AAXX indicates that the report type 
follows the WMO SYNOP FM-12 code. Land stations provide the 
date/time group as do ship stations (see above) through the YYGGiw 
group. This message usually appears at the start of a bulletin 
which may contain many reports (see example below). The IIiii 
group is for the WMO block number (II) and station number (iii) 
within each block.

   In the US, the block numbers are:

41                       Tropical North Atlantic Ocean (buoys)
42                       Gulf of Mexico (buoys)
44                       Extratropical N Atlantic Ocean (buoys)
45                       Great Lakes (buoys)
46                       Tropical NE Pacific Ocean (buoys)
51                       Extratropical NE Pacific Ocean (buoys)
70                       Alaska
71                       Canada
72                       Contiguous US (civilian)
74                       US (military)*
76                       Mexico
78                       Central America and Caribbean
80                       South America/Caribbean stations
91                       Hawaii and US Pacific territories

   WMO station numbers generally start with 200 and increase to 
the west along a latitude band, and then at 300 you move up the 
next latitude band, on the eastern edge of the block number, etc. 
The southeastern US has station numbers in the low 200's and the 
Pacific Northwest has station numbers in the high 700's.

For ships :

     BBXX  DDDD  YYGGiw  99LaLaLa QcLoLoLoLo

   WMO SYNOP FM-13 is the standard reference for ship SYNOP, which 
will be designated in the heading by BBXX.  It is published in the 
US by the Navy, and it is also available several places online.  
SYNOP, like METAR, can also be decoded online.

   Since buoys are fixed ships, they provide latitude and 
longitude positions, but also use a WMO station number format 
(IIiii) rather than the ship ID format DDDD. CMAN (coastal-marine) 
stations are special types of automated observing stations 
installed primarily to replace the old lighthouse stations which 
were staffed by Coast Guard observers. These stations also report 
in the synoptic code format.

IIiii The WMO number of the station.
Ship or Buoy Observations: 
IIIII The ship or buoy identifier 
YYGGi 
YY -- The day of the month
GG  -- The hour of the observation (UTC)
iw -- Wind type indicator 
0 -- m/s (estimated)
1 -- m/s (from anemometer)
2 -- knots (estimated)
3 -- knots (from anemometer) 
99LLL QLLLL
LLL -- Latitude of observation to .1 degrees
Q -- Quadrant of observation 
1 -- North east 
3 -- South east
5 -- South west
7 -- North west 
LLLL -- Longitude of  observation to .1 degrees 

Section 1: International Land Observations
------------------------------------------

  iRixhVV  Nddff  1snTTT  2snTdTdTd  3PoPoPoPo  4PPPP
  5appp  6RRRtR  7wwW1W2  8NhCLCMCH 9GGgg

111 Group - Land Observations 
iihVV
iR -- Precipitation indicator 
0 -- Precipitation in groups 1 and 3
1 -- Precipitation reported in group 1 only
2 -- Precipitation reported in group 3 only
3 -- Precipitation omitted, no precipitation
4 -- Precipitation omitted, no observation 
ix -- Station type and present and past weather indicator 

1 -- manned station -- weather group included
2 -- manned station -- omitted, no significant weather
3 -- manned station -- omitted, no weather observation
4 -- automated station -- weather group included (see automated 
weather codes 4677 and 4561)
5 -- automated station -- omitted, no significant weather
6 -- automated station -- omitted, no weather observation
7 -- automated station -- weather group included (see automated 
weather codes 4680 and 4531) 
h -- Cloud base of lowest cloud seen (meters above ground) 

0 -- 0 to 50 m 
1 -- 50 to 100 m 
2 -- 100 to 200 m
3 -- 200 to 300 m
4 -- 300 to 600 m
5 -- 600 to 1000 m
6 -- 1000 to 1500 m
7 -- 1500 to 2000 m
8 -- 2000 to 2500 m
9 -- above 2500 m
/ -- unknown 
VV -- Visibility 

00 -- less than 0.1 km
01 -- 0.1 km
02 -- 0.2 km
...
50 -- 5.0 km
56 -- 6 km
57 -- 7 km
...
80 -- 30 km
81 -- 35 km
82 -- 40 km
83 -- 45 km
84 -- 50 km
85 -- 55 km
86 -- 60 km
87 -- 65 km
88 -- 70 km
89 -- greater than 70 km
90 -- less than 0.05 km
91 -- 0.05 km
92 -- 0.2 km
93 -- 0.5 km
94 -- 1 km
95 -- 2 km
96 -- 4 km
97 -- 10 km
98 -- 20 km
99 -- greater than 50 km
// -- missing 
Nddff
N -- Total cloud cover 
0 -- 0 eighths (clear)
1 -- 1/8th
2 -- 2/8ths
3 -- 3/8ths
4 -- 4/8ths
5 -- 5/8ths
6 -- 6/8ths
7 -- 7/8ths
8 -- 8/8ths (overcast)
9 -- sky obscured
/ -- no observation 
dd -- wind direction in 10s of degrees 
ff -- wind speed in units determined by wind type indicator (see 
above) 

00fff (optional)
fff -- wind speed if value greater than 100 
1sTTT -- Temperature
s -- sign of temperature (0=positive, 1=negative)
TTT -- Temperature in .1 C 
2sTTT -- Dewpoint
s -- sign of temperature (0=positive, 1=negative, 9 = RH)
TTT -- Dewpoint temperature in .1 C (if sign is 9, TTT is relative 
humidity) 
3PPPP -- Station pressure in 0.1 mb (thousandths digit omitted, 
last digit can be slash, then pressure in full mb) 
4PPPP -- Sea level pressure in 0.1 mb (thousandths digit omitted, 
last digit can be slash, then pressure in full mb)
4ahhh -- Geopotential of nearest mandatory pressure level (use for 
high altitude stations where sea level pressure reduction is not 
accurate)
a3 -- mandatory pressure level 
1 -- 1000 mb
2 -- 925 mb
5 -- 500 mb
7 -- 700 mb
8 -- 850 mb 
hhh -- geopotential height omitting thousandths digit 

5appp -- Pressure tendency over 3 hours
a -- characteristics of pressure tendency 
0 -- Increasing, then decreasing -- resultant pressure same or 
higher
1 -- Increasing, then steady -- resultant pressure higher
2 -- Increasing steadily -- resultant pressure higher
3 -- Decreasing or steady, then increasing -- resultant pressure 
higher
4 -- Steady -- resultant pressure same
5 -- Decreasing, then increasing -- resultant pressure lower
6 -- Decreasing, then steady -- resultant pressure lower
7 -- Decreasing steadily -- resultant pressure lower
8 -- Increasing or steady, then decreasing -- resultant pressure 
lower 
ppp -- 3 hour pressure change in 0.1 mb 

6RRRt -- Liquid precipitation
RRR -- Precipitation amount in mm 
001 -- 1 mm
002 -- 2 mm
...
988 -- 988 mm
989 -- 989 or more mm
990 -- Trace
991 -- 0.1 mm
992 -- 0.2 mm
...
999 -- 0.9 mm 
t -- Duration over which precipitation amount measured 

1 -- 6 hours
2 -- 12 hours
3 -- 18 hours
4 -- 24 hours
5 -- 1 hour
6 -- 2 hours
7 -- 3 hours
8 -- 9 hours
9 -- 15 hours
/ -- 24 hours 

7wwWW -- Present and past weather
ww -- Present weather 
00 -- clear skies
01 -- clouds dissolving
02 -- state of sky unchanged
03 -- clouds developing
Haze, smoke, dust or sand
04 -- visibility reduced by smoke
05 -- haze
06 -- widespread dust in suspension not raised by wind
07 -- dust or sand raised by wind
08 -- well developed dust or sand whirls
09 -- dust or sand storm within sight but not at station
Non-precipitation events
10 -- mist
11 -- patches of shallow fog
12 -- continuous shallow fog
13 -- lightning visible, no thunder heard
14 -- precipitation within sight but not hitting ground
15 -- distant precipitation but not falling at station
16 -- nearby precipitation but not falling at station
17 -- thunderstorm but no precipitation falling at station
18 -- squalls within sight but no precipitation falling at station
19 -- funnel clouds within sight
Precipitation within past hour but not at observation time
20 -- drizzle
21 -- rain
22 -- snow
23 -- rain and snow
24 -- freezing rain
25 -- rain showers
26 -- snow showers
27 -- hail showers
28 -- fog
29 -- thunderstorms
Duststorm, sandstorm, drifting or blowing snow
30 -- slight to moderate duststorm, decreasing in intensity
31 -- slight to moderate duststorm, no change
32 -- slight to moderate duststorm, increasing in intensity
33 -- severe duststorm, decreasing in intensity
34 -- severe duststorm, no change
35 -- severe duststorm, increasing in intensity
36 -- slight to moderate drifting snow, below eye level
37 -- heavy drifting snow, below eye level
38 -- slight to moderate drifting snow, above eye level
39 -- heavy drifting snow, above eye level
Fog or ice fog
40 -- Fog at a distance
41 -- patches of fog
42 -- fog, sky visible, thinning
43 -- fog, sky not visible, thinning
44 -- fog, sky visible, no change
45 -- fog, sky not visible, no change
46 -- fog, sky visible, becoming thicker
47 -- fog, sky not visible, becoming thicker
48 -- fog, depositing rime, sky visible
49 -- fog, depositing rime, sky not visible
Drizzle
50 -- intermittent light drizzle
51 -- continuous light drizzle
52 -- intermittent moderate drizzle
53 -- continuous moderate drizzle
54 -- intermittent heavy drizzle
55 -- continuous heavy drizzle
56 -- light freezing drizzle
57 -- moderate to heavy freezing drizzle
58 -- light drizzle and rain
59 -- moderate to heavy drizzle and rain
Rain
60 -- intermittent light rain
61 -- continuous light rain
62 -- intermittent moderate rain
63 -- continuous moderate rain
64 -- intermittent heavy rain
65 -- continuous heavy rain
66 -- light freezing rain
67 -- moderate to heavy freezing rain
68 -- light rain and snow
69 -- moderate to heavy rain and snow
Snow
70 -- intermittent light snow
71 -- continuous light snow
72 -- intermittent moderate snow
73 -- continuous moderate snow
74 -- intermittent heavy snow
75 -- continuous heavy snow
76 -- diamond dust
77 -- snow grains
78 -- snow crystals
79 -- ice pellets
Showers
80 -- light rain showers
81 -- moderate to heavy rain showers
82 -- violent rain showers
83 -- light rain and snow showers
84 -- moderate to heavy rain and snow showers
85 -- light snow showers
86 -- moderate to heavy snow showers
87 -- light snow/ice pellet showers
88 -- moderate to heavy snow/ice pellet showers
89 -- light hail showers
90 -- moderate to heavy hail showers
Thunderstorms
91 -- thunderstorm in past hour, currently only light rain
92 -- thunderstorm in past hour, currently only moderate to heavy 
rain
93 -- thunderstorm in past hour, currently only light snow or 
rain/snow mix
94 -- thunderstorm in past hour, currently only moderate to heavy 
snow or rain/snow mix
95 -- light to moderate thunderstorm
96 -- light to moderate thunderstorm with hail
97 -- heavy thunderstorm
98 -- heavy thunderstorm with duststorm
99 -- heavy thunderstorm with hail 
W1 -- Past weather (type 1)
W2 -- Past weather (type 2) 

0 -- cloud covering less than half of sky
1 -- cloud covering more than half of sky during part of period 
and more than half during part of period
2 -- cloud covering more than half of sky
3 -- sandstorm, duststorm or blowing snow
4 -- fog, or thick haze
5 -- drizzle
6 -- rain
7 -- snow or mixed rain and snow
8 -- showers
9 -- thunderstorms 

8NCCC -- Cloud type information
N -- Amount of low clouds covering sky, if no low clouds, the 
amount of the middle clouds
CL -- Low cloud type 
0 -- no low clouds
1 -- cumulus humulis or fractus (no vertical development)
2 -- cumulus mediocris or congestus (moderate vertical 
development)
3 -- cumulonimbus calvus (no outlines nor anvil)
4 -- stratocumulus cumulogenitus (formed by spreading of cumulus)
5 -- stratocumulus
6 -- stratus nebulosus (continuous sheet)
7 -- stratus or cumulus fractus (bad weather)
8 -- cumulus and stratocumulus (multilevel)
9 -- cumulonimbus with anvil
/ -- low clouds unobserved due to darkness or obscuration 
CM -- Middle cloud type 

0 -- no middle clouds
1 -- altostratus translucidous (mostly transparent)
2 -- altostratus opacus or nimbostratus
3 -- altocumulus translucidous (mostly transparent)
4 -- patches of altocumulus (irregular, lenticular)
5 -- bands of altocumulus
6 -- altocumulus cumulogenitus (formed by spreading of cumulus)
7 -- altocumulus (multilayers)
8 -- altocumulus castellanus (having cumuliform tufts)
9 -- altocumulus of a chaotic sky
/ -- middle clouds unobserved due to darkness or obscuration 
CH -- High cloud type 

0 -- no high clouds
1 -- cirrus fibratus (wispy)
2 -- cirrus spissatus (dense in patches)
3 -- cirrus spissatus cumulogenitus (formed out of anvil)
4 -- cirrus unicus or fibratus (progressively invading sky)
5 -- bands of cirrus or cirrostratus invading sky (less than 45 
degree above horizon)
6 -- bands of cirrus or cirrostratus invading sky (more than 45 
degree above horizon)
7 -- cirrostratus covering whole sky
8 -- cirrostratus not covering sky but not invading
9 -- cirrocumulus 
/ -- high clouds unobserved due to darkness or obscuration 
9GGgg -- Time of observation in hours and minutes 

Section 2: International Sea Surface Observations
-------------------------------------------------

222Dv 0sTTT 1PPHH 2PPHH 3dddd 4PPHH 5PPHH 6IEER 70HHH 8aTTT

222Dv 
D -- direction of ship movement 
0 -- calm
1 -- NE
2 -- E
3 -- SE
4 -- S
5 -- SW
6 -- W
7 -- NW
8 -- N
9 -- unknown 
v -- ship's average speed 
0 -- 0 knots
1 -- 1 to 5 knots
2 -- 6 to 10 knots
3 -- 11 to 15 knots
4 -- 16 to 20 knots
5 -- 21 to 25 knots
6 -- 26 to 30 knots
7 -- 31 to 35 knots
8 -- 36 to 40 knots
9 -- over 40 knots 
0sTTT -- Sea surface temperature
s -- sign of temperature (0=positive, 1=negative)
TTT -- Temperature in .1 C 
1PPHH -- Wave heights in 0.5 m increments 
PP -- Period of waves in seconds
HH -- Height of waves in 0.5 m increments 
2PPHH -- Wave period and heights (instrumented) 
3dddd -- Direction of swells (up to 2 swells) 
4PPHH -- Period and direction of first set of swells 
5PPHH -- Period and direction of second set of swells 
6IEER -- Ice accretion on ships 
70HHH -- Wave heights to 0.1 m (instrumented) 
8aTTT -- Wet bulb temperature 

Section 3: Special Regional or Climatological Data
--------------------------------------------------

333 0.... 1sTTT 2sTTT 3Ejjj 4Esss 5jjjj jjjjj 6RRRt 7RRRR 8Nchh 
9SSss 

333
0.... -- Regionally developed data 
1sTTT -- Maximum temperature over previous 24 hours
s -- sign of temperature (0=positive, 1=negative)
TTT -- Temperature in .1 C 
2sTTT -- Minimum temperature over previous 24 hours
s -- sign of temperature (0=positive, 1=negative)
TTT -- Temperature in .1 C 
3Ejjj -- Regionally developed data 
4Esss -- Snow depth 
E -- State of ground with snow cover 
0 -- predominantly covered with ice
1 -- compact or wet snow covering less than half of ground
2 -- compact or wet snow covering more than half of ground but not 
completely covered
3 -- even layer of compact or wet snow covering entire ground
4 -- uneven layer of compact or wet snow covering entire ground
5 -- loose dry snow covering less than half of ground
6 -- loose dry snow covering more than half of ground but not 
completely covered
7 -- even layer of loose dry snow covering entire ground
8 -- uneven layer of loose dry snow covering entire ground
9 -- snow covering ground completely with deep drifts 
sss -- snow depth in cm 

5jjjj jjjjj -- Additional information (can be multiple groups) 
6RRRt -- Liquid precipitation
RRR -- Precipitation amount in mm 
001 -- 1 mm
002 -- 2 mm
...
988 -- 988 mm
989 -- 989 or more mm
990 -- Trace
991 -- 0.1 mm
992 -- 0.2 mm
...
999 -- 0.9 mm 
t -- Duration over which precipitation amount measured 
1 -- 6 hours
2 -- 12 hours
3 -- 18 hours
4 -- 24 hours
5 -- 1 hour
6 -- 2 hours
7 -- 3 hours
8 -- 9 hours
9 -- 15 hours
/ -- 24 hours 
7RRRR -- 24 hour precipitation in mm 
8NChh -- Cloud layer data
N -- cloud coverage of layer
C -- genus of cloud 
0 -- cirrus (Ci)
1 -- cirrocumulus (Cc)
2 -- cirrostratus (Cs)
3 -- altocumulus (Ac)
4 -- altostratus (As)
5 -- nimbostratus (Ns)
6 -- stratocumulus (Sc)
7 -- stratus (St)
8 -- cumulus (Cu)
9 -- cumulonimbus (Cb)
/ -- cloud not visible 
hh -- height of cloud base 
00 -- less than 30 m
01 -- 30 m (100 ft)
02 -- 60 m (200 ft)
03 -- 90 m (300 ft)
...
50 -- 1500 m (5000 ft)
56 -- 1800 m (6000 ft)
57 -- 2100 m (7000 ft)
...
80 -- 9000 m (30000 ft)
81 -- 10500 m
82 -- 12000 m
...
88 -- 21000 m
89 -- greater than 21000 m
90 -- 0 to 50 m 
91 -- 50 to 100 m 
92 -- 100 to 200 m
93 -- 200 to 300 m
94 -- 300 to 600 m
95 -- 600 to 1000 m
96 -- 1000 to 1500 m
97 -- 1500 to 2000 m
98 -- 2000 to 2500 m
99 -- above 2500 m 
9SSss -- Supplementary information 
333            identifier for section 3
1snTxTxTx      6-hr maximum temperature 
2snTnTnTn      6-hr minimum temperature
4E'sss         E' is the state of the ground (normally / in the 
US) and sss is the depth of snow on the ground, in cm.
7R24R24R24R24  24-hr precipitation amount, in 0.1 mm increments
8NsChshs       This group is for the encoding of multiple cloud 
layers in terms of the ten basic cloud groups; each cloud group 
(identified by the C) may cover up to Ns oktas of the sky and may 
have a base encoded in hshs.
9SPSPspsp      These are for special phenomena.

Section 4: Not used
----------------------------------------------------

Section 5: Meteorological data for national exchange
----------------------------------------------------
Begins with 555 if present

In the US:

555  [RECORD]  [0itDtDtDt]  [1snTT snTxTxsnTnTn]  
  [RECORD]  [2R24R24R24R24]
  [marine/CMAN stations] 11fff10 22fff20 3GGggvx 4dddffvx 
                         6GGgg dddfff0 dddfff1 dddfff2 dddfff3
                         dddfff4 dddfff5
  [US land stations] 9YYGG is repeated

[] = optional

Appendix #5: BUOY Code
======================

The header SSVX identifies bulletins of observations coded in FM 
18-X.

Note: This code form replaced the former FM 18-IX Ext DRIFTER 
code.

Observations from buoys similar to observations from ships are 
encoded in the SHIP code, FM 12 or FM 13, and are included in 
bulletins headed SMV/, SIV/ etc.

For a full decode please refer to the WMO Manual on Codes, Volume 
I.1 Part A: Alphanumeric codes, WMO Publication No 306, available 
from: The WMO Secretariat at PO Box 2300, CH-1211 Geneva 2, 
Switzerland, price Sw Fr 130.- (February 1998) 

The following Sections are only included if there are data
available
 
SECTION 0  Identification, time and position data 
           MiMiMjMj A1bwnbnbnb YYMMJ GGggiw QcLaLaLaLaLa
           LoLoLoLoLoLo (6QiQt//)

SECTION 1  Meteorological and other non-marine data
           (111QdQx 0ddff 1snTTT 2snTdTdTd OR 29UUU 3P0P0P0P0
           4PPPP 5appp

SECTION 2  Surface marine data
           (222QdQx 0snTwTwTw 1PwaPwaHwaHwa ..... .....

SECTION 3  Temperatures, salinity and current (when available) 
           at selected depths 
           333Qd1Qd2 .....  .....

SECTION 4  Information on engineering and technical parameters 
           including quality control data) 
           444 (1QpQ2QTwQ4) ..... .....

INTERPRETATION

SECTION 0 (Identification, time and position data)

MiMiMjMj                  Always coded as ZZYY 

A1bwnbnbnb                The buoy number or identifier
              A1bw        The WMO Region and sub-region in which
                          the buoy was deployed, eg 62 includes
                          the seas around the UK and to the west
                          and south-west of the British Isles.
             nbnbnb       Type and serial number of the buoy (500
                          is added to the serial number when the
                          buoy is a drifting buoy)

YYMMJ        YY          Date
             MM          Month
             J           Last digit of the year

GGggiw       GGgg        Time of the observation
             iw          Indicator for source and units of wind
                         speed
                         0 or 1: Wind speed metres/sec;
                         3 or 4: Wind speed knots

QcLaLaLaLaLa  Qc          Quadrant of the globe
                          N hemisphere: 7 is degrees West, 1 is
                          degrees East
                          S hemisphere: 5 is degrees West, 3 is
                          degrees East
             LaLaLaLaLa   Latitude (eg 54126 decoded as 54.126
                          degrees, 54.12/  decoded as 54.12
                          degrees and 541// as 54.1 degrees)

LoLoLoLoLoLo              Longitude (eg 132463 decoded as 132.463
                          degrees, 05621/decoded as 56.21 degrees,
                          and 1458// as 145.8 degrees

(6QiQt//)                Quality control indicators (see WMO
                         Manual on Codes)

SECTION 1 (Meteorological and other non-marine data)

111QdQx               Quality control indicators for the section

0ddff       0         Indicator
            dd        Wind direction in tens of degrees
            ff        Wind speed in knots or m/s

1snTTT      1         Indicator
            sn        Sign of temperature - 0: positive or zero,
                      1: negative
            TTT       Dry-bulb temperature in tenths of a degree
                      Celsius

2snTdTdTd    2         Indicator
            sn         Sign of temperature
            TdTdTd     Dew-point temperature in tenths of a degree
                       Celsius

  OR

29UUU       2         Indicator
            9         Relative humidity follows
            UUU       Relative humidity expressed as a percentage:
                        first figure zero except when UUU is 100
                        percent

3P0P0P0P0    3         Indicator
            P0P0P0P0   Pressure at station level, in tenths 
                        of a millibar, omitting the thousands
                        digit

4PPPP       4         Indicator
            PPPP      Mean sea level pressure, in tenths of a
                        millibar, 
                        omitting the thousands digit

5appp       5         Indicator
            a         Characteristic of pressure change
            ppp       Pressure change over last three hours in
                        tenths of a millibar