Hillsborough County

New Hampshire

 SKYWARN Documentation

Covering the towns of Amherst, Bedford, Bennington, Brookline, Francestown, Goffstown, Greenfield, Greenville, Hancock, Hollis, Hudson, Litchfield, Lyndenborough, Mason, Merrimack, Milford, Mont Vernon, Nashua, New Boston, New Ipswich, Pelham, Peterborough, Sharon, Temple, Wilton, and Manchester New Hampshire.

 

Date of Last Revision: July 10, 2002 Revision 1.8

 Warning Coordination Meteorologist: Glenn A. Field

 ARES SKYWARN Coordinator: Robert D. Macedo KD1CY

Hillsborough Emergency Coordinator: Don Dillaby KA1GOZ

Hillsborough ARES SKYWARN Liaison: Marc Slater - KB1DFE

 

Purpose

 

This document provides information for SKYWARN network control operators within  Hillsborough County. The document is organized into the following sections:

 

Section I - Introduction to SKYWARN

Section II - Activation Procedure and Contact Personnel

Section III - Activation Levels

Section IV - Net Operations

Section V – Liaison with NWS Taunton

Appendix A –   Hillsborough County SKYWARN Frequencies

Appendix B – Reporting Criteria and Priorities

Appendix C – NWS WeatherRadio and SAME Codes for Hillsborough County New Hampshire and Surrounding Area

Appendix D - Suggested Equipment List for Net Control Operators

Appendix E - Tornado Classifications

Appendix F - Hurricane Classifications

Appendix G - Estimating Windspeed

Appendix H - Estimating Hail Size

Appendix I - Change History

 

I. Introduction to SKYWARN

 

 The National Weather Service SKYWARN system’s goal is for the public to report precise and dependable information to NWS weather meteorologists for the protection of life and property. For members of the public to achieve SKYWARN status, the National Weather Service Office’s Warning Coordination Meteorologist offers training so that anyone can become trained in SKYWARN and assist the National Weather Service in its prime objective.

 

Amateur radio operators perform a unique service for the National Weather Service. With their mobile radio transmitters, technical knowledge, and NWS certified SKYWARN training, Amateur Radio SKYWARN weather observers activate SKYWARN or Severe Weather Emergency Nets, which in conjunction with the general public, provide the National Weather Service with validation of severe weather reports throughout the coverage area.

 

Despite the technological advances provided by Doppler Radar, the only way fully valid information of severe weather can be disseminated to the public, is through validation of the radar reports through ground based weather spotters. The general public can report this information via telephone or through public service officials. Amateur radio operators can report this information via telephone or by voice and packet transmissions.

 

The National Weather Service Forecast Office in Taunton, Massachusetts can receive reports from weather spotters and public safety officials, and also from amateur radio operators via voice and packet communications. This allows NWS to take reports from the public even if telephone communications were to be interrupted.

 

II. Activation Procedure and Contact Personnel

 

The Southern New England ARES SKYWARN Spotter Network for NWS Taunton may be activated under the following conditions:   

 

        Whenever a severe thunderstorm, tornado, hurricane, or flood watch is issued.

        Whenever a winter storm, blizzard, or high wind warning is issued

        If, in the lead forecaster’s opinion there is a strong potential for severe weather

 

The network is activated by a phone call from the lead forecaster at NWS to the ARES SKYWARN Coordinator. The ARES SKYWARN Coordinator is:

 

ROBERT MACEDO (KD1CY)

(H): (508) 994-1875

(W): 1-800-445-2588  Ext.: 72929

Pager: (508) 354-3142

Cellular: (508) 259-9213

Home Email: rmacedo@pop.ma.ultranet.com

Work Email: macedo_robert@isus.emc.com

 

The ARES SKYWARN Coordinator activating SKYWARN will:

 

        Phone the appropriate areas for which SKYWARN activation is required or will likely be required in the next few hours.

        Be sure that the NWS Taunton Amateur Radio Station is manned with at least one and possibly two Amateur Radio Operators.

        Assist in any other way possible to expedite activation of the ARES/SKYWARN Network for the region.

 

The ARES SKYWARN Coordinator will contact the following personnel in the order that they appear in order to activate SKYWARN in  Hillsborough County.

 

Once notification has been received, that individual is expected to bring up a SKYWARN net on the Pack Monadnock and Hollis NH repeater systems, solicit weather reports from any stations on frequency, and relay those reports to NWS Taunton.

 

Please note that if severe weather is observed, and no net is active, any amateur can activate the net to warn other amateurs, and begin collecting weather observations.

 

Hillsborough County Ham Activation List:

 

Marc Slater (KB1DFE)

SKYWARN Liaison

    (H) (603) 673-1674

(W): (603) 878-5055 ext 5130

 Email: slater@mas.mv.com Cell: 603-930-5757

 

Steve Maloney (N1JDK)

Assistant Emergency Coordinator

 
(H): (603) 472-8996
Email: n1jdk@attbi.com

 

 Fletcher Seagroves (N1MEO)
(H) (603)  673-3036 (Cell) (603) 470-7508
Email: seagrove@n1meo.mv.com

 

Donald Grant (N1UBD)

Assistant Emergency Coordinator

(H): (603) 429-1128
Email: n1ubd@arrl.net

 

 

Larry Levesque (KA1VGM)

Assistant Emergency Coordinator

(H): (603) 424-3353
Email: ka1vgm@adelphia.net

 

 

Don Dillaby (KA1GOZ)

Emergency Coordinator Hillsborough County

(H): (603) 888-2766 (W): (603) 598-4444
Email: ddillaby@attbi.com

William Fleming (N1HKO)

Assistant Emergency Coordinator Manchester

(H): (603) 668-5926
Email: n1hko@arrl.net

 

If no one on the list above can be contacted, the following individual should be called to assist.

 

Tom Matisko (N1SKZ)

Section Emergency Coordinator

(H): (603) 464-4095 (W): (603) 424-2725
Email: t_matisko@conknet.com

 

This net will relay reports to NWS via the Spotter line, Packet, or via the NWS liaison frequencies.  The amateur radio operator running the NWS Taunton amateur radio station may also check in and field reports from these weather nets.  Appendix A contains the commonly used SKYWARN net and liaison frequencies for  Hillsborough County.

 

III. Activation Levels

 

The level of activation, and the response of the amateur community, depends on the nature and severity of the weather event.  Nets may be activated in stand-by mode, as an informal net, or as a formal, directed net.  

 

The level of activation gives an indication of the severity of the impending weather and how wide spread the impact of the weather is expected to be.  A Level III activation implies a more localized impact, and is the lowest level of activation. A Level I activation implies a more wide spread, more urgent response is required, and is the highest level of activation.

 

In most cases, the level of activation and the status of the SKYWARN net is set at the discretion of the local ARES SKYWARN operator.

 

SUMMERTIME ACTIVATIONS:

 

Level III:            While severe weather is not expected at a widespread level, some scattered thunderstorms may approach and reach severe levels in a given time period. SKYWARN activation in various local areas may be necessary in case a Severe Thunderstorm or Special Marine Warning is issued for a localized area (one or two counties.).  Net control operators will initiate a stand-by net and escalate the status of the SKYWARN net as the situation dictates.  This is the lowest level of activation.

 

Level II:            The potential exists for severe weather over a widespread area. A Weather Watch Issuance (Severe Thunderstorm, Tornado, Flood, Hurricane Watch) requires Stand-By Activation of SKYWARN. This means that NCS’s and contact people should be near a amateur radio and monitor the situation as it develops. Particularly with Severe Thunderstorm Tornado and Flood Watches, amateur operators should prepare for possible severe weather within a few hours of the Watch issuance and have a SKYWARN net standing by on frequency in case severe weather warrants a directed net later.

 

Level I:            When Severe Thunderstorm, Special Marine, Tornado, Flood or Hurricane Warnings have been issued for the specified area, a directed net should be instituted. Particularly in Severe Thunderstorm, Tornado, and Flood Warnings, a directed net should be instituted immediately after the warning is issued. In a hurricane warning, the net can remain in stand-by mode until the first feeder bands of the hurricane reach the coast, then the status of the net can be escalated to a directed net. This is the highest level of activation.

 

WINTERTIME ACTIVATIONS:

 

Level II:            For Winter Weather Advisories, hourly or bi-hourly activation’s for Snowfall Reports, Road Conditions and any type of damage can be forwarded. Also, location of the snow/ice/rain line can be forwarded, as it is difficult to detect on radar. Final reports on snowfall or after a changeover to rain can be forwarded.

 

Level I:            If Blizzard Warnings, High Wind Warnings, Coastal Flood Warnings, Winter Storm and Flood Warnings are issued for the region, this will require at least hourly activation of SKYWARN, and perhaps formal directed net mode if reports of damage and weather warrant. Snowfall, rainfall, and damage reports as well as the rain/ice/snow line should be reported.

 

Appendix C describes prioritization and what to report.

 

IV. Net Operations

 

As stated previously, the primary purpose of the SKYWARN program is to assist the National Weather Service in gathering information to make an accurate prediction. SKYWARN operators should update the amateur community of the situation, and maintain the status of the net in line with the current weather situation.

 

The flow of the net is generally:

 

        announce the net

        take check ins

        designate net control operators for secondary SKYWARN frequencies

        allow stations with announcements to transmit their information

        ask for reports of severe weather on a regular basis

        relay reports of severe weather to NWS Taunton

 

The following procedure is recommended as a guideline to amateur operators when they prepare to activate a SKYWARN net.

 

The SKYWARN net control operator should contact the Emergency Coordinator for  Hillsborough Country, by one of the methods listed in Section II.

 

2.) The SKYWARN net control operator should start a log. This log need not show every single contact, but it should show the following:

 

        Time of Activation.

        When Watches and Warnings were sent out.

        Time, frequency, location (by city and county), and call signs and names of stations reporting severe weather that will be used in NWS Taunton statements

        Weather observations per the following format:

        Time of report (in local 24hr format)

        Callsign of reporting station

        Temperature

        Skycover (overcast, mostly cloudy, partly cloudy, clear)

        Wind direction

        Wind speed

        Wind gust

        Barometer (and rising or falling)

        Type of precipitation currently falling (if any)

        Total precip for the storm

        Moisture content

        Any additional notes from that station

        Time of deactivation.

        Any other significant events that occurred relating to SKYWARN.

 

3) Open the net as follows:

 

Calling the   Hillsborough County SKYWARN net.  Calling the  Hillsborough County SKYWARN net.   This is <call>, net control for the   Hillsborough County SKYWARN net.  My name is <name>, and I am located in <town, state>.

 

4) If the net is in response to a formal SKYWARN activation, bring the net up as a directed net:

 

This is a directed net in response to a formal SKYWARN activation.  Stations should transmit only when directed to do so by net control.   The only exception to this is for emergency, priority, or time sensitive traffic.

 

5) If the net is in response to a stand-by or informal SKYWARN activation, bring the net up as an informal net.

 

This is a stand-by (informal) net in response to a stand-by (informal) SKYWARN activation.

 

6) Invite check-ins

 

All amateurs are welcome to join the net, and you do not have to be a member of SKYWARN or the Amateur Radio Emergency Services to join the net.

 

When checking into the net, please announce yourself with the words "THIS IS", followed by a carrier drop to check for doubling, then give your call sign phonetically, followed by your name and your location.

 

The first call up will be for Emergency Coordinators, Assistant Emergency Coordinators, and Liaison stations.  Any ECs, AECs, or liaisons wishing to check into the net, please call <call>.

 

7) After ECs, AECs, and liaisons have been checked in, take general check ins.

 

This is <call>, net control for the  Hillsborough SKYWARN net.  Any stations, anywhere, wishing to check into the net please call now with your callsign, name, and location.

 

8) As each station or group of station checks in, acknowledge them by stating:

 

Net recognizes <call>, <name> in <location>, thanks for checking in please stand by.

 

 

Or alternatively:

 

Net recognizes <call1>, <call2>, …, thanks for checking in, please stand by.

 

9) After check ins have been received, pass control to the Emergency Coordinator or any Assistant Emergency Coordinators on frequency, and invite them to make any announcements or an informal, then pass control back to net control.

 

After ECs, AECs, and liaisons have made their announcements, transmit any of your announcements that have not been covered to the net.  If NWS has published a severe weather statement, this might be an appropriate point to transmit the statement.  See Section VI on how to obtain information from the NWS.

 

10) The net control station should identify themselves and the net every 10 minutes.  Ask for any reports of severe weather, and for any further check ins.  Reannounce the purpose of the net at least every 30 minutes.  For example:

 

This is KB1DFE, net control for the  Hillsborough SKYWARN net looking for reports of strong or severe weather.  Reports of (tornadoes, funnel clouds, or rotating funnel clouds, hail, wind 40 MPH or greater, flooding, heavy downpours, wind or lightning damage, and closed or impassable roads) are of particular interest. Stations with reports please call now.

 

Not everything in the script needs to be read, but at least a portion of that information should be read so that the proper description of reports is given to NWS meteorologists.

 

If the SKYWARN net is active for a winter event this example script should be used in some form:

 

This is KB1DFE, net control for the  Hillsborough SKYWARN net looking for reports of severe weather. Reports of (snowfall totals, severe icing, sleet or freezing rain, wind in excess of 40 miles per hour, damage reports and impassable or closed roads) are of particular interest. Stations with reports please call now.

 

11) Finally, when National Weather Service meteorologists issue weather statements, watches and warnings, if time allows, the operator should read the statement as written by the NWS forecaster. No changes or deletions should be made. If there is not enough time to read the statement, be sure to give a clear and concise summary on watches, warnings and reports to the weather spotters, so they can guide their roving spotters to next “hot spots” of severe weather, and react to changing weather situations.

 

12.) All reports of damage meeting the strong or severe criteria of severe weather should be logged. NWS meteorologists will use this information in their Local Storm Report or Other Public Products report and later in the printed publication called Storm Data.  See Appendix C for reporting criteria.


 

VI. Liaison with NWS Taunton

 

This section describes the methods with which the SKYWARN net control operator and other amateur radio weather spotters can interface with National Weather in times of severe weather.

 

        The NWS spotter line. (Should not be given over the air.) In general, only those who have received NWS training and have received a spotter card and number have the hot line number.  Net control operators should also have the hot line number in order to be able to relay reports of severe weather directly to NWS Taunton, especially if the operator at NWS cannot be raised on any of the liaison frequencies.  Contact the SKYWARN Liaison listed in Section II to obtain the hot line number.

        Call the NWS at the toll-free number.

        Identify yourself with your Spotter ID # and your name.

        BRIEFLY describe WHAT was observed; and WHEN & WHERE it was observed.

        If you cannot reach NWS and you consider your report to be life-threatening, call your local police or fire department, explain who you are, and ask that they relay the report to the NWS.

 

        The net control operator at NWS Taunton may monitor area weather nets from time to time. Liaison frequencies are listed in Appendix A.  The net control operator running the SKYWARN net should listen on one or more of the liaison frequencies, announce themselves from time to time, and call the NWS Taunton operator if needed to pass along reports of severe weather.

 

        In the case where the NWS Taunton operator checks into the active SKYWARN net, the net control operator should pass along any reports of severe weather on behalf of the net. 

 

        If the status of the net is stand-by or informal, the net control operator should identify themselves and append /SKYWARN to their call, and then attempt to relay any formal reports to the NWS operator to avoid wasting time.

 

Up to date hard copy of NWS bulletins are available from the following Internet locations:

        National SKYWARN page - http://www.skywarn.org/weather.htm

        NWS site - http://iwin.nws.noaa.gov/iwin/nationalwarnings.html

        Weather.com - http://www.weather.com/ and type your zip code into the appropriate box

        Another NWS link - http://tgsv5.nws.noaa.gov/er/box/


 

Appendix A:  Hillsborough County SKYWARN Frequencies

 

This section lists the frequencies that may be used during SKYWARN activation in  Hillsborough County. Please note that nets should be activated on the Pack Monadnock NH 443.350, the Hollis NH 146.730 repeater system, the Nashua NH 147.045 repeater, and the Francestown 146.685 repeater.

 

It is strongly recommended that the station initiating the first SKYWARN net in an event call the net on the Pack Mondanock repeater, and as stations check into the net, designate stations to act as net control operators on the Nashua, Hollis, and Francestown repeaters.

This section lists the frequencies that may be used during SKYWARN activation in   Hillsborough County.  Please note that nets should be activated on the Pack Monadnock NH 443.350 and the Hollis NH 146.730 repeater systems.  If net traffic becomes heavy, it is recommended that a fixed station with separate 70cm and 2M transceivers be designated as net control on the Hollis NH 146.730 repeater and relay information to the Pack Monadnock 443.350 repeater as needed.

 

 

Use

Tactical Name

Frequency

PL

Location

Primary SKYWARN

ARES1

443.350

110.9

Pack Monadnock NH

Secondary SKYWARN

ARES2

146.730

88.5

Hollis NH

- linked

ARES2

443.500

88.5

Hollis NH

- linked

ARES2

442.150

88.5

Pat’s PeakHenniker  NH

- linked

ARES2

448.825

88.5

Leominster MA

- linked

ARES2

53.930

88.5

Brookline NH

- linked

ARES2

449.375

88.5

Brookline NH

- linked

ARES2

146.730

151.4

Brookline NH RX only

Secondary SKYWARN

ARES3

147.045

100.0

Nashua, NH

Secondary SKYWARN

ARES4

146.685

100.0

Francestown, NH

Secondary SKYWARN ARES5 147.330 127.2 Manchester NH

Primary simplex

ARES6

147.42

 

Simplex

Secondary simplex

ARES7

147.48

 

Simplex

Primary liaison frequency to NWS Taunton

ARES1

443.350

110.9

Pack Monadnock NH

Secondary liaison frequency to NWS Taunton

ARES8

53.310

71.9

Mt. Wachusett MA

Granite State FM Traffic Net

ARES9

146.940

 

Concord NH, daily at 20:30 local

Granite State Phone Traffic Net

ARES10

3942 kHz

 

LSB 3942 kHz, 6:30 PM Daily

LSB 3945 kHz, 9:30 AM Sunday

Primary APRS

ARES11

144.390

 

 

Primary Packet

ARES12

145.030

 

Node: BBSSNH

Secondary Packet

ARES13

145.030

 

Node: WA1WOK

Weather Preparedness Net

 

7231.5 kHz or 3993.5 kHz

 

LSB Sunday 9:30 am

 


 Appendix B: Reporting Criteria and Priorities

 

Please report whenever you observe the following:

        Tornadoes or funnel clouds (be very wary of look-alikes; watch for rotation)

        Wall clouds, especially if they are rotating

        Hail (Be specific with regard to size; DO NOT report MARBLE size, see the section on Estimating Hail Size)

        Winds (40 mph or greater; specify whether estimated or recorded)
-- large branches downed (specify diameter of branch)
-- Trees/power lines downed
-- Structural damage to buildings (roof, windows, etc.)

        Rainfall
-- 1 inch or greater in an hour (NOT a 1"/hr. rate for 10 minutes)
-- 2 inches or greater storm total

        Flooding
-- Streams/Rivers -- also, when nearing bankfull
-- Coastal
-- Street (when more than the usual poor drainage puddles)

        Winter Weather
-- Precipitation type change (rain to sleet/freezing rain/snow, when the
change has "taken hold")
-- Thunder, when accompanied by snow
-- 1/3" radial ice accretion (from twig outward; not circumference)

        New Snowfall
-- First 2 inches; every 2-3 inches thereafter
-- 1 inch per hour or greater
-- If less than 2 inches total, give final total only
-- Give final total (don't leave us hanging with a partial report)
-- Report any snow/sleet/freezing rain if not in NWS forecast!


Appendix C: National Weather Service WeatherRadio and SAME Codes for Counties Surrounding Hillsborough County New Hampshire

 

SAME stands for Specific Area Message Encoding.

 

When an NWS office broadcasts an urgent audio message (warning, watch, or non-weather emergency) it also creates and broadcasts a digital SAME code (that may be heard as a very brief static burst, depending on the characteristics of the receiver). This SAME code contains the type of message, county(s) affected, and expiration time of the message.

 

An appropriately programmed NWR SAME receiver will then turn on for that message, with the listener hearing the 1050 Hz warning alarm tone as an attention signal, followed by the broadcast message.

 

At the end of the broadcast message, listeners will hear a brief digital end-of-message static burst followed by a resumption of the NWR broadcast cycle.

 

Here are the SAME codes for Hillsborough County, and surrounding counties.

 

St

County

SAME #

NWR

Freq.

Call

Watts

Remarks

NH 

Belknap

033001

Concord NH

162.400

WXJ40

330

Central/S

 

Cheshire

033005

Worcester MA

162.550

WXL93

500

South

 

Cheshire

033005

Concord NH

162.400

WXJ40

330

NE

 

Cheshire

033005

Windsor VT

162.475

WXN44

400

West

 

Cheshire

033005

Marlboro VT

162.425

WXM68

330

Far SE

 

Hillsborough

033011

Worcester MA

162.550

WXL93

500

South

 

Hillsborough

033011

Concord NH

162.400

WXJ40

330

 

 

Merrimack

033013

Concord NH

162.400

WXJ40

330

 

 

Rockingham

033015

Concord NH

162.400

WXJ40

330

 

 

Sullivan

033019

Concord NH

162.400

WXJ40

330

East

 

Sullivan

033019

Windsor VT

162.475

WXN44

400

West

 

Sullivan

033019

Marlboro VT

162.425

WXM68

330

SW

MA

Essex

025009

Boston MA

162.475

KHB35

500

 

 

Franklin

025011

Hartford CT

162.475

WXJ41

300

South

 

Franklin

025011

Worcester MA

162.550

WXL93

500

Central/E

 

Franklin

025011

Windsor VT

162.475

WXN44

400

North

 

Franklin

025011

Marlboro VT

162.425

WXM68

330

North

 

Middlesex

025017

Boston MA

162.475

KHB35

500

Near NW

 

Middlesex

025017

Worcester MA

162.550

WXL93

500

Central/W

 

Worcester

025027

Hartford CT

162.475

WXJ41

300

SW

 

Worcester

025027

Worcester MA

162.550

WXL93

500

 

 

 


Appendix D - Suggested Equipment List for Net Control Operators

 

In order to maintain a minimum level of preparedness for SKYWARN activations, here is a suggested list of equipment that net control operators might keep on hand in anticipation of being called to activate a SKYWARN net.

 

        This document

        Paper and writing instruments, including log sheets

        Ear phones

        Flash lights

        Battery operated lamp

        Extra batteries

        Indoor antennas for 2M and 70cm (and possibly 6M)

        Transceivers (hand held or base) for 2M and 70cm (and possibly 6M)

        Weather radio or scanner tuned to the appropriate NWS WeatherRadio

        Alternate power sources for transceivers, scanners, receivers, and lamps

 

Appendix E - Tornado Classifications

 

The Fujita or F-Scale applies to the strength of tornadoes, and runs from F0 to F5.

 

        F0 and F1, or minor tornadoes have wind speeds on the order of 110 mph. Winds of this speed will peel back roof shingles, and push moving automobiles off the road.

        F2 and F3, or moderate tornadoes have wind speeds between 113 and 205 mph. Winds of this strength will tear off roofs and walls, snap large trees, and lift cars off the ground.

        F4 and F5, or severe tornadoes have winds between 206 and 318 mph. A tornado of this type will level a well constructed house, blow structures a distance off of their foundations, and sweep the ground clear of debris.

 

Appendix F - Hurricane Classifications

 

The Saffir/Simpson scale is used to classify the damage potential of a tropical cyclone. Storms of this nature fall into categories ranked from 1 to 5.

 

        A Category 1, or minimal hurricane, has winds between 74 and 95 mph.

        A Category 2, or moderate hurricane, has winds between 96 and 110 mph.

        A Category 3, or extensive hurricane, has winds between 111 and 130 mph.

        A Category 4, or extreme hurricane, has winds between 131 and 155 mph.

        A Category 5, or catastrophic hurricane, has winds greater than 155 mph.


 

Appendix G - Estimating Windspeeds

 

The Beaufort scale of wind speeds was originally developed for estimating winds at sea, but has been adapted for use on land. The scale runs from Beaufort Force 0...calm, to Force 12...Hurricane or wind speeds greater than 74 mph.

 

Here is a simplified guide to estimating winds.

 

        If large tree limbs are in motion and the wind whistles through wires...winds are between 25 and 30 mph.

        When whole trees are in motion and it is difficult to walk against the wind...winds are between 30 and 40 mph.

        When twigs break off trees or the wind generally impedes you from walking...and slight structural damage is done to chimneys or shingles...estimate winds between 40 and 55 mph. Start reporting to NWS if winds reach this level!

        If the winds are causing widespread damage to roofs and antennas; and shallow rooted trees are pushed over...the winds are between 55 and 70 mph.

        If roofs begin to peel off; windows are broken; small trailers are moved or overturned; or moving vehicles are pushed off the road...estimate the winds over 70 mph. Winds of this speed can occur from downburst or straightline winds in any thunderstorm, tornadoes, and hurricanes.

 

Appendix H - Estimating Hail Size

The following are the hail sizes that the national weather service equates with various terminology,

 

Description

What to report

Severity

Pea

1/4 inch

not severe

Marble

1/2 inch

not severe

Mothball

1/2 inch

not severe

Dime

3/4 inch

severe

Penny

3/4 inch

severe

Nickel

7/8 inch

severe

Quarter

1 inch

severe

Half dollar

1 1/4 inches

severe

Walnut

1 1/2 inches

severe

Ping pong ball

1 1/2 inches

severe

Golf ball

1 3/4 inches

severe

Hen egg

2 inches

severe

Tennis ball

2 1/2 inches

severe

Baseball

2 3/4 inches

severe

Tea cup

3 inches

severe

Grapefruit

4 inches

severe

Softball

4 1/2 inches

severe

 

 

 

Appendix I - Change History

 

1.4 08/08/99 Added revision history, corrected the callup list and frequency table
1.5 09/15/99 Added additional frequencies
1.6 11/12/00 Added additional frequencies, updated the contact list
1.7 04/17/01 Added various appendices
1.8 07/10/02 Edits to reflect the merging of Eastern and Western Hillsborough, updated the contact list