1 hail, as filed by the National Weather Service.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Chicago, IL wrote its last area forecast discussion before the first event at Aug 18, 2:34 AM CST, 9 hours 46 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO IL 300 AM CDT SAT AUG 18 2001 THE 500 MB TROUGH OVER MINNESOTA AND IOWA HAS COLD ADVECTION AT LOW LEVELS AND A JET STREAK OVER THE DAKOTAS JUST TO THE WEST. THE TROUGH SHOULD DEEPEN SOME MORE AS IT MOVES EAST. THE LAYER BETWEEN 800 AND 600 MB IS VERY DRY AS SEEN ON THE ILX SOUNDING. RADAR SHOWS SHOWERS AND THUNDERSTORMS MOVING INTO EASTERN IOWA AND WESTERN WISCONSIN. THERE WAS POSITIVE MOISTURE ADVECTION AT 700 MB AT 00 UTC. THIS ADVECTION WAS OVER IOWA AND BEGINNING TO MOVE INTO NORTHWEST ILLINOIS. SURFACE DEWPOINTS AND WIND ANALYSIS SHOWS MOISTURE ADVECTION AT THE SURFACE. INCREASE IN MOISTURE WILL CONTINUE THROUGH THE EARLY MORNING. WILL KEEP LIKELY POPS IN THE FORECAST. USING THE ACARS SOUNDINGS AND ADJUSTING THEM FOR CHANGES. FIND THAT THE ATMOSPHERE BECOMES UNSTABLE LATER TODAY. WILL USE GUIDANCE AND WILL STAY CLOSE TO GUIDANCE FOR THE FORECAST HIGHS AND LOWS. .CHI...NONE. WHW
ILZ003>006-008-010>014-019>023-032>033-039-INZ001>002-010>011-019- 191100- SEVERE WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHICAGO IL 1200 PM CDT/EST SAT AUG 18 2001 FOR NORTH CENTRAL AND NORTHEAST ILLINOIS AND NORTHWEST INDIANA THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EARLY EVENING FOR NORTHWEST INDIANA AND EAST CENTRAL ILLINOIS. THE THREAT AREA INCLUDES AREAS EAST AND SOUTH OF A LINE FROM ABOUT MICHIGAN CITY INDIANA TO KANKAKEE ILLINOIS TO PONTIAC ILLINOIS. THERE IS SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EARLY THIS EVENING FOR NORTHEAST AND NORTH CENTRAL ILLINOIS INCLUDING CHICAGO AND ROCKFORD. A DEVELOPING LOW IN WEST CENTRAL ILLINOIS IS EXPECTED TO STRENGTH THIS AFTERNOON. THE LOW WILL MOVE ACROSS AN AREA OF INCREASINGLY UNSTABLE AIR AND HELP PRODUCE STRONG TO SEVERE THUNDERSTORMS...ESPECIALLY IN THE MODERATE RISK AREA. THE THREATS FROM THE STORMS WILL BE LARGE HAIL...DAMAGING WINDS...AND SOME TORNADOES. BE ALERT FOR THREATENING WEATHER CONDITIONS THIS AFTERNOON. STAY TUNED TO WEATHER RADIO OR YOU FAVORITE TV OR RADIO STATION FOR DEVELOPING WEATHER INFORMATION THROUGHOUT THE AFTERNOON SOMREK
The Lincoln radar (KILX), 87 km away, was scanning. The volume nearest the first event began at 18:18 UTC.
1 hail. Local standard time, as filed.
A slow moving thunderstorm moved across southern Ford county during the early afternoon on August 18th, producing hail as large as half dollars across most of southern Ford county.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2001Every state in 2001This day in weather historyWarnings in Illinois, August 2001
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5264254.