Chicagoland Skywarn

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What should I report?

Report these observations to your local Skywarn net control. He/she will determine if it warrants passing the report on to the National Weather Service.


Organized, persistent, sustained rotation


Organized, persistent, sustained rotation


Nickel size or larger. Report the largest size hailstone


40 mph or higher. Specify estimate or measurement


Flooding that impacts roads, homes or businesses.


1/4 inch or more within a 15 minute period.


Damage to structures (roof, siding, windows, etc)
Damage to vehicles (from hail or wind)
Trees uprooted or large limbs down
Power/telephone poles or lines down, or direct lighning strike injuries


1" or more per hour, accumulations of 2" or more


Ice jams on rivers or streams

Again, reports should provide as much detail as possible to describe the where, when, how, etc of the event.

Some commonly used hail sizes
Pea .25 inch Golf Ball 1.75 inch
Half-inch .50 inch Hen Egg 2.00 inch
Dime .75 inch Tennis Ball 2.50 inch
Nickel .88 inch Baseball 2.75 inch
Quarter 1.00 inch Tea Cup 3.00 inch
Half Dollar 1.25 inch Grapefruit 4.00 inch
Ping Pong Ball 1.50 inch Softball 4.50 inch

General Guidelines for Estimating Wind Speeds
30-44 mph (26-39 kt) Whole trees in motion. Inconvenient walking into the wind. Light-weight loose objects (e.g., lawn furniture) tossed or toppled.
45-57 mph (39-49 kt) Large trees bend; twigs, small limbs break and a few larger dead or weak branches may break. Old/weak structures (e.g., sheds, barns) may sustain minor damage (roof, doors). Buildings partially under construction may be damaged. A few loose shingles removed from houses.
58-74 mph (50-64 kt) Large limbs break; shallow rooted trees pushed over. Semi-trucks overturned. More significant damage to old/weak structures. Shingles, awnings removed from houses; damage to chimneys and antennas.
75-89 mph (65-77 kt) Widespread damage to trees with large limbs down or trees broken/uprooted. Mobile homes may be pushed off foundation or overturned. Roof may be partially peeled off industrial/commercial/ warehouse buildings. Some minor roof damage to homes. Weak structures (e.g., farm buildings, airplane hangars) may be severely damaged.
90+ mph (78+ kt) Many large trees broken and uprooted. Mobile homes damaged. Roofs partially peeled off homes and buildings. Moving automobiles pushed off the road. Barns, sheds demolished.

How Should I Report an Obervation?

(ranked by NWS preference)
FIRST CHOICE: On your local Skywarn Amateur Radio Reporting Repeater!
SECOND CHOICE: Toll Free, 1-800-681-2972

ALL reports should include the following information:

WHO are you? Report your ham callsign or spotter ID (or phone number, or any other means of identification) so the NWS can contact you to verify the report. Without this information, the NWS cannot use your report.
WHAT did you see?
WHERE did you see it? Report the location/approximate location of the event. Be sure to distinguish clearly between where you are and where the event is thought to be happening (.I.m 5 miles north of Mayberry. The tornado looks to be about 5 miles to my northwest.).
WHEN did you see it? Be sure that reports that are relayed through multiple sources carry the time of the event, NOT the report time.
Any other details that are important - How long did it last? Direction of travel? Was there damage? etc.

Daily Spotter and Co-Op Station Reports

Snowfall Totals using Google Earth or Static Graphics

Climatology from Weather Underground

Palwaukee Arpt.-Wheeling