Storm Spotter/Skywarn Information

Skywarn 
A Guide for National
Weather Service Storm Spotters
2004 Edition
   

The Spotters Role in a Warning:

  1. Validate severe storm warnings
  2. Vital Information source for the National Weather Service
  3. Provide a link to the community in the warning process
  4. Aids in local hazard awareness
  5. Spotters are NOT chasers.

Information Needed From a Spotter:

  1. Confirmed tornado
  2. Tornado precursors such as a funnel cloud or wall cloud
  3. Measured wind speed in excess of 50 mph (please note the key word measured)
  4. Flooding
  5. Measured rainfall in excess of one inch
  6. Any size hail
  7. Damage...injuries or deaths
  8. Verification of public reports of severe weather

 

DO NOT REPORT THESE CONDITIONS:

  1. It's raining really hard here
  2. I am at this location and I don't see anything here.
  3. The sky is very dark
  4. Boy, there is a lot of lightning here.
  5. The rain has stopped here.
  6. We have blue sky.
  7. It was raining here but now it has stopped.
  8. What will the weather do tomorrow?
  9. Have not seen any hail or experienced gusty winds

Wind Speed Estimates

25 - 31 Large branches in motion; whistling in telephone wires
32 - 38 Whole trees in motion
39 - 54 Twigs break off of trees; wind impedes walking
55 - 72 Damage to chimneys and TV antennas; pushes over shallow rooted trees
73 - 112 Peels surface off roofs; windows broken; trailer houses overturned
113+ Roofs torn off houses; weak buildings and trailer houses destroyed; large trees uprooted

 

 
Hail Reporting Measurements (in inches)   Fujita Damage Scale
Pea (0.25")  
Penny (0.75")
Quarter (1.00")  
Half Dollar (1.25")  
Golf Ball (1.75")  
Tennis Ball (2.50")  
Baseball (2.75")  
Grapefruit (4.00")  
   
   
   
 
F0 Gale Tornado weak 40 - 72 mph
F1 Moderate Tornado weak 73 - 112 mph
F2 Significant Tornado strong 113 - 157 mph
F3 Severe Tornado strong 158 - 206 mph
F4 Devasting Tornado violent 207 - 260 mph
F5 Incredible Tornado violent 261 - 318 mph

 

 

 

 

 

 

 

 

Location of above information.

 

    All hail size is important to the National Weather Service (NWS). Please relay all reports of hail to the your local law enforcement agency and have them relay the report to the NWS. Please do not report the hail as marble size. There is much confusion as marbles vary in size. To lessen confusion, please use the above table as a guide. If the hail is smaller than 0.75 inches, try to use measurements. If a measurement is not possible, compare the hail to a common item such as a pea or bb pellet.

Remember that Skywarn is a National Weather Service program. Not an ARRL or ARES program. Follow the instructions/procedures of the served agency.

What is Skywarn?

Other Skywarn Links:

Glossary of Weather Terms for Storm Spotters.