Alert archive / Illinois / Severe Thunderstorm Warnings in 1987
Severe Thunderstorm Warning 3, NWS Quad Cities, IA
NWS Quad Cities, IA issued this severe thunderstorm warning at May 21, 1987, 6:39 PM CDT for Henry County, Illinois. It was in force for 21 min.
The area
The counties it named.
The facts
- Issued
- May 21, 1987, 6:39 PM CDT (23:39 UTC)
- Expired
- May 21, 1987, 7:00 PM CDT
- In force
- 21 min
- Issued by
- NWS Quad Cities, IA
- Area
- Whole counties
County Henry County, IL
The radar
The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.
The nearest sounding before it
Peoria Regional, IL (KPIA), launched 12:00Z, 11.7 hours before the alert went out and 88 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
- 795 J/kg
- Mixed-layer CIN
- -86 J/kg
- Mixed-layer LCL
- 1074 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 45 m²/s²
- 0-3 km storm-relative helicity
- 112 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 0.5
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.
In the hours before
Special weather statement, May 21, 3:44 PM CDT, 2 hours 55 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DUBUQUE IA 345 PM CDT THU MAY 21 1987 ...TORNADO WATCH UNTIL 9 PM FOR GRANT AND LAFAYETTE COUNTIES IN SOUTHWEST WISCONSIN... AT 340 PM CDT THUNDERSTORMS WERE DEVELOPING RAPIDLY IN GRANT COUNTY IN EXTREME SOUTHWESTERN WISCONSIN. THESE THUNDERSTORMS WERE MOVING TO THE NORTHEAST AT 30 TO 40 MILES AN HOUR. NO SEVERE WEATHER HAS BEEN REPORTED FROM THESE THUNDERSTORMS AS OF 340 THIS AFTERNOON. JPERSONS IN SOUTHWESTERN WISCONSIN SHOULD BE ON THE LOOKOUT FOR SEVERE WEATHER AND BE PREPARED TO TAKE COVER IF THREATENING WEATHER APPROACHES ASMUS
Special weather statement, May 21, 4:30 PM CDT, 2 hours 9 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DUBUQUE IA 430 PM CDT THU MAY 21 1987 ...TORNADO WATCH UNTIL 9 PM FOR GRANT AND LAFAYETTE COUNTIES IN SOUTHWEST WISCONSIN... ...TORNADO WATCH FOR DELAWARE...DUBUQUE...JACKSON...AND JONES COUNTIES IN NORTHEAST IOWA UNTIL 10 PM CDT... AT 425 PM CDT THUNDERSTORMS WERE DEVELOPING RAPIDLY ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN. THESE THUNDERSTORMS WERE MOVING TO THE NORTHEAST AT 30 TO 40 MILES AN HOUR. NO SEVERE WEATHER HAD BEEN REPORTED FROM THESE THUNDERSTORMS AS OF 425 THIS AFTERNOON. PERSONS IN TRI-STATE AREA SHOULD BE ON THE LOOKOUT FOR SEVERE WEATHER AND BE PREPARED TO TAKE COVER IF THREATENING WEATHER APPROACHES. A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR THE DEVELOPEMENT OF SEVERE THUNDERSTORMS AND TORNADOES IN AND NEAR THE WATCH AREA. A TORNADO WARNING OR SEVERE THUNDERSTORM WARNING MEANS ACTUAL CONDITIONS HAVE BEEN SIGHTED AND IMMEDIATE ACTION SHOULD zBE TAKEN. ASMUS
Special weather statement, May 21, 5:25 PM CDT, 1 hour 14 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DUBUQUE IA 525 PM CDT THU MAY 21 1987 ...TORNADO WATCH UNTIL 9 PM FOR GRANT AND LAFAYETTE COUNTIES IN SOUTHWEST WISCONSIN... ...TORNADO WATCH FOR DELAWARE...DUBUQUE...JACKSON...AND JONES COUNTIES IN NORTHEAST IOWA UNTIL 10 PM CDT... AT 520 PM CDT THUNDERSTORMS WERE DEVELOPING RAPIDLY FROM EASTERN MISSOURI...ACROSS EASTERN IOWA INTO SOUTHWEST WISCONSIN. THESE THUNDERSTORMS WERE ALL MOVING TO THE NORTHEAST AT 30 TO 40 MILES AN HOUR. NO STRONG THUNDERSTORM ACTIVITY WAS INDICATED IN THE DUBUQUE TRI-STATE AREA...HOWEVER THERE WERE SOME SCATTERED THUNDERSHOWERS. NO SEVERE WEATHER HAD BEEN REPORTED FROM THESE THUNDERSTORMS AS OF 520 THIS AFTERNOON. PERSONS IN TRI-STATE AREA SHOULD BE ON THE LOOKOUT FOR SEVERE WEATHER AND BE PREPARED TO TAKE COVER IF THREATENING WEATHER APPROACHES. REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR THE DEVELOPEMENT OF SEVERE THUNDERSTORMS AND TORNADOES IN AND NEAR THE WATCH AREA. A TORNADO WARNING OR A SEVERE THUNDERSTORM WARNING MEANS ACTUAL CONDITIONS HAVE BEEN SIGHTED AND IMMEDIATE ACTION SHOULD BE TAKEN. ASMUS
Special weather statement, May 21, 6:18 PM CDT, 21 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE MOLINE IL 617 PM CDT THU MAY 21 1987 ...STRONG THUNDERSTORMS MOVING THROUGH SOUTHEAST IOWA... AT 615 PM CDT A BAND OF THUNDERSTORMS EXTENDED FROM SOUTHEAST IOWA INTO NORTHEAST MISSOURI. THE STRONGEST WAS LOCATED JUST WEST OF MOUNT PLEASANT IN SOUTHEAST IOWA. OTHER STRONG THUNDERSTORMS WERE ALONG THE WASHINGTON/LOUISA COUNTY LINE OR ABOUT 50 MILES SOUTHWEST OF THE QUAD CITIES. SOME BRIEF HE^AVY RAIN..SMALL HAIL AND STRONG GUSTY WINDS MAY ACCOMPANY THESE THUNDERSTORMS. MOVEMENT WAS TO THE NORTHEAST ABOUT 25 MPH. WIGGINS
Special weather statement, May 21, 6:21 PM CDT, 18 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DUBUQUE IA 620 PM CDT THU MAY 21 1987 ...TORNADO WATCH UNTIL 9 PM FOR GRANT AND LAFAYETTE COUNTIES IN SOUTHWEST WISCONSIN... ...TORNADO WATCH FOR DELAWARE...DUBUQUE...JACKSON...AND JONES COUNTIES IN NORTHEAST IOWA UNTIL 10 PM CDT... AT 615 PM CDT SCATTERED THUNDERSTORMS WERE MOVING OUT OF NORTHERN DUBUQUE COUNTY...IN NORTHEAST IOWA...INTO SOUTHWESTERN GRANT COUNTY ...IN SOUTHWEST WISCONSIN. THE THUNDERSTORMS WERE MOVING TO THE NORTHEAST AT 40 MILES AN HOUR. THESE THUNDERSTORMS MAY PRODUCE HEAVY RAIN AND BREIF GUSTY WINDS AS THEY MOVE ACROSS GRANT COUNTY WISCONSIN. NO INDICATIONS OF SEVERE WEATHER HAD BEEN NOTICED FROM THESE THUNDERSTORMS. NO SEVERE WEATHER HAD BEEN REPORTED FROM THESE THUNDERSTORMS AS OF 615 THIS AFTERNOON. PERSONS IN TRI-STATE AREA SHOULD BE ON THE LOOKOUT FOR SEVERE WEATHER AND BE PREPARED TO TAKE COVER IF THREATENING WEATHER APPROACHES. REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR THE DEVELOPEMENT OF SEVERE THUNDERSTORMS AND TORNADOES IN AND NEAR THE WATCH AREA. A TORNADO WARNING OR A SEVERE THUNDERSTORM WARNING MEANS ACTUAL CONDITIONS HAVE BEEN SIGHTED AND IMMEDIATE ACTION SHHOULD BE TAKEN. ASMUS
Nearby
Severe Thunderstorm Warnings in Illinois, 1987Every severe thunderstorm warning in 1987
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.