Alert archive / Illinois / Severe Thunderstorm Warnings in 1991
Severe Thunderstorm Warning 21, NWS Chicago, IL
NWS Chicago, IL issued this severe thunderstorm warning at May 16, 1991, 3:41 PM CDT for Cook County, Illinois; Lake County, Indiana. It was in force for 49 min. 1 report came from inside the area while it was in force.
The area
The counties it named, with what was reported inside it.
The facts
- Issued
- May 16, 1991, 3:41 PM CDT (20:41 UTC)
- Expired
- May 16, 1991, 4:30 PM CDT
- In force
- 49 min
- Issued by
- NWS Chicago, IL
- Area
- Whole counties
Counties Cook County, IL, Lake County, IN
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| May 16, 4:25 PM CDT | Thunderstorm Wind 0 | Cook, IL |
NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.
The nearest sounding before it
Green Bay/Straub, WI (KGRB), launched 12:00Z, 8.7 hours before the alert went out and 315 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
- 4 J/kg
- Mixed-layer CIN
- -169 J/kg
- Mixed-layer LCL
- 876 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- 71 m²/s²
- 0-3 km storm-relative helicity
- 120 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KCHI 162043 SVRCHI ILC031-INC089-162130- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM AND SPECIAL MARINE WARNING NATIONAL WEATHER SERVICE CHICAGO IL 341 PM CDT THU MAY 16 1991 THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A SEVERE THUNDERSTORM AND SPECIAL MARINE WARNING EFFECTIVE UNTIL 430 PM CDT FOR PEOPLE IN THE FOLLOWING LOCATIONS... IN NORTHEAST ILLINOIS ...SOUTHEASTERN COOK COUNTY IN NORTHWEST INDIANA ...WESTERN LAKE COUNTY AT 3 35 PM CDT... A SEVERE THUNDERSTORM WAS DETECTED CROSSING THE BORDER FROM WILL COUNTY INTO SOUTHEAST COOK COUNTY NEAR CHICAGO HEIGHTS. RESIDENTS IN SOUTHEAST COOK AND WESTERN LAKE COUNTY OF NORTHWEST INDIANA SHOULD BE PREPARED FOR POSSIBLE LARGE HAIL AND STRONG WINDS. THIS STORM MAY SURVIVE TO MOVE INTO THE COASTAL WATERS OF SOUTHERN LAKE MICHIGAN. WHEN THUNDERSTORMS ARE OCCURRING...PEOPLE SHOULD MOVE INSIDE A STRONG BUILDING. DO NOT STAND BY WINDOWS. DON'T USE TELEPHONES OR ELECTRICAL APPLIANCES UNLESS IN AN EMERGENCY UNTIL THE STORM HAS PASSED. MOTORISTS SHOULD NOT DRIVE INTO LOW WATER CROSSINGS.
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.
In the hours before
Special weather statement, May 16, 10:37 AM CDT, 5 hours 4 minutes before
ILZALL-162100- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHICAGO IL 1100 AM CDT THU MAY 16 1991 THE NATIONAL SEVERE STORMS FORECAST CENTER IN KANSAS CITY SAYS THERE IS A SLIGHT CHANCE OF A FEW LSEVERE THUNDERSTORMS THIS AFTERNOON AND EARLY THIS EVENING OVER EASTERN ILLINOIS. LEBDA
Special weather statement, May 16, 1:07 PM CDT, 2 hours 34 minutes before
ILZ003-008-160100- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHICAGO IL 1 00 PM CDT THU MAY 16 1991 THE NATIONAL SEVERE STORMS FORECAST CENTER HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR THE EAST QUARTER OF ILLINOIS UNTIL 8 00 PM TONIGHT. THE COUNTIES IN OUR LISTENING AREA UNDER THIS WATCH INCLUDE DUPAGE...WILL...COOK...KANKAKEE...FORD...IROQUOIS...AND LIVINGSTON COUNTIES. THUNDERSTORMS WILL BE SCATTERED ACROSS ILLINOIS THIS AFTERNOON AND EARLY TONIGHT. THOSE STORMS IN FAR EASTERN ILLINOIS COULD REACH SEVERE POTENTIAL. SEVERE THUNDERSTORM CRITERIA INCLUDES THREE-QUARTER INCH HAIL OR BETTER...WINDS GUSTS GREATER THAN 60 MPH...OR POSSIBLE TORNADIC DEVELOPMENT. BRUMER
Special weather statement, May 16, 1:18 PM CDT, 2 hours 23 minutes before
ILZ003-008-160100- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHICAGO IL 1 15 PM CDT THU MAY 16 1991 SEVERE THUNDERSTORM WATCH CONTINUES IN EFFECT FOR A PORTIONS OF EASTERN AND NORTHEAST ILLINOIS AND THE CHICAGO METRO AREA UNTIL 8 PM CDT. AT 1 00 PM CDT SCATTERED STRONG THUNDERSTORMS WERE DEVELOPING NEAR CHAMPAIGN. THE THUNDERSTORMS WERE MOVING NORTH AT AROUND 30 MPH AND WILL BE MOVING INTO FORD COUNTY NEAR THE TOWNS OF PAXTON... MELVIN AND PIPER CITY AND INTO IROQUOIS COUNTY NEAR THE TOWNS OF LODA ONARAGA AND WATSEKA BETWEEN 1 15 PM AND 2 00 PM CDT THIS AFTERNOON. A FEW OF THE STORMS WILL LIKELY PRODUCE BRIEF HEAVY DOWMPOURS... STRONG GUSTY WINDS... POSSIBLE HAIL AND FREQUENT ,LIGHTNING. LEBDA
Special weather statement, May 16, 2:09 PM CDT, 1 hour 32 minutes before
ILZ003-008-162000- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHICAGO IL 210 PM CDT THU MAY 16 1991 A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR PART OF EASTERN AND NORTHEAST ILLINOIS...INCLUDING THE CHICAGO METRO AREA...UNTIL 8PM CDT. AT 205 PM SHOWERS AND THUNDERSTORMS WERE SCATTERED ACROSS MUCH OF CENTRAL AND EASTERN ILLINOIS. THE STRONGEST STORMS WERE 20 MILES SOUTHEAST OF WATSEKA IN SOUTHERN IROQUOIS COUNTY AND 15 MILES SOUTHEAST O F PONTIAC IN LIVINGSTON COUNTY. THE STORMS WERE MOVING NORTH AT 25 MPH. THESE STORMS COULD PRODUCE HAIL AND STRONG GUSTY WINDS. ALLSOPP
Special weather statement, May 16, 2:44 PM CDT, 57 minutes before
ILZ003-008-162100- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHICAGO IL 243 PM CDT THU MAY 16 1991 A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR PART OF EASTERN AND NORTHEAST ILLINOIS...INCLUDING THE CHICAGO METRO AREA...UNTIL 8PM CDT. AT 240 PM THUNDERSTORMS WERE OVER PARTS OF NORTHWEST INDIANA... NORTHEAST AND EAST CENTRAL ILLINOIS. THE STRONGEST STORM WAS 10 MILES EAST OF PONTIAC. IT COULD PRODUCE HAIL AND STRONG GUSTY WINDS. ANOTHER STRONG STORM WAS 20 MILES EAST OF KANKAKEE AND SOUTH OF GARY ON THE INDIANA/ILLINOIS BORDER. A SEVERE THUNDERSTORM WAS IN EASTERN MCLEAN COUNTY EAST OF BLOOMINGTON. THE STORMS WERE MOVING NORTH AT 25 MPH. SEEK SHELTER INDOORS AWAY FROM WINDOWS< IF THREATENING WEATHER APPROACHES. REPORT SEVERE WEATHER TO THE NEAREST LAW ENFORCEMENT AGENCY FOR RELAY TO THE WEATHER SERVICE. ALLSOPP
Special weather statement, May 16, 3:28 PM CDT, 13 minutes before
ILZ003-005-008-162130- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHICAGO IL 325 PM CDT THU MAY 16 1991 A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR PART OF EASTERN AND NORTHEAST ILLINOIS...INCLUDING THE CHICAGO METRO AREA...UNTIL 8PM CDT. AT 315 PM THUNDERSTORMS WERE OVER PARTS OF NORTHWEST INDIANA... NORTHEAST AND EAST CENTRAL ILLINOIS. THE STRONGEST STORM WAS 20 MILES WEST SOUTHWEST OF KANKAKEE...JUST WEST OF THE LIVINGSTON/KANKAKEE COUNTY LINE. THIS STORM WILL LIKELY MOVE NORTH INTO SOUTHEASTERN GRUNDY...AND ACROSS WESTERN KANKAKEE COUNTY INTO SOUTHWESTERN WILL COUNTY. ANOTHER STRONG STORM WAS 15 MILES NORTHEAST OF KANKAKEE JUST WEST OF THE INDIANA STATE LINE. THIS STORM WILL MOVE NORTH INTO FAR EASTERN WILL COUNTY. ANOTHER STRONG STORM WAS MOVING OUT OF NORTHEAST MCLEAN COUNTY TOWARDS SOUTH CENTRAL LIVINGSTON COUNTY. NO SEVERE WEATHER HAS BEEN REPORTED FROM ANY OF THESE STORMS BUT THE POTENTIAL FOR DAMAGING WINDrS...LARGE HAIL...FREQUENT LIGHTNING AND EVEN A TORNADO EXISTS. KEEP ALERT TO THE WEATHER CONDITIONS AND HEAD FOR A PLACE OF SAFETY IF THREATENING WEATHER APPROACHES YOU. SEELEY
The office that day
Everything else NWS Chicago, IL issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 16, 1:42 PM CDT | Severe Thunderstorm Warning | LOT | Iroquois | 48 min |
| May 16, 4:08 PM CDT | Severe Thunderstorm Warning | LOT | Cook | 37 min |
Nearby
Severe Thunderstorm Warnings in Illinois, 1991Severe Thunderstorm Warnings in Indiana, 1991Every severe thunderstorm warning in 1991
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.