Alert archive / Illinois / Severe Thunderstorm Warnings in 2001
Severe Thunderstorm Warning 56, NWS Chicago, IL
NWS Chicago, IL issued this severe thunderstorm warning at Aug 18, 2001, 1:26 PM CDT for Ford County, Livingston County, Illinois. It was in force for 64 min. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Aug 18, 2001, 1:26 PM CDT (18:26 UTC)
- Expired
- Aug 18, 2001, 2:30 PM CDT
- In force
- 64 min
- Issued by
- NWS Chicago, IL
- Area
- Whole counties
Counties Ford County, IL, Livingston County, IL
The radar
The Chicago radar (KLOT), 99 km from the middle of the area, began a volume at 18:30 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Aug 18, 12:30 PM CDT | Tornado Watch | SPC | 6 hr |
The nearest sounding before it
Lincoln, IL (KILX), launched 12:00Z, 6.4 hours before the alert went out and 68 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 192 J/kg
- Mixed-layer CIN
- -146 J/kg
- Mixed-layer LCL
- 1002 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 92 m²/s²
- 0-3 km storm-relative helicity
- 136 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.
What forecasters said that day
The local office's own words before this severe thunderstorm warning went out, 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 this severe thunderstorm warning went out at Aug 18, 3:34 AM CDT, 9 hours 52 minutes earlier.
Area forecast discussion, Aug 18, 3:34 AM CDT, 9 hours 52 minutes before
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
In the hours before
Special weather statement, Aug 18, 12:14 PM CDT, 1 hour 12 minutes before
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 office that day
Everything else NWS Chicago, IL issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 18, 12:53 PM CDT | Severe Thunderstorm Warning | LOT | Ford, Iroquois | 37 min |
| Aug 18, 12:53 PM CDT | Severe Thunderstorm Warning | LOT | Livingston | 37 min |
| Aug 18, 2:03 PM CDT | Severe Thunderstorm Warning | LOT | Iroquois | 27 min |
| Aug 18, 2:48 PM CDT | Severe Thunderstorm Warning | LOT | Benton | 27 min |
Nearby
Severe Thunderstorm Warnings in Illinois, 2001Every severe thunderstorm warning in 2001
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.