Alert archive / Illinois / Severe Thunderstorm Warnings in 1999
Severe Thunderstorm Warning 66, NWS St. Louis, MO
NWS St. Louis, MO issued this severe thunderstorm warning at Apr 21, 1999, 12:40 AM CDT for Brown County, Illinois. It was in force for 35 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
- Apr 21, 1999, 12:40 AM CDT (05:40 UTC)
- Expired
- Apr 21, 1999, 1:15 AM CDT
- In force
- 35 min
- Issued by
- NWS St. Louis, MO
- Area
- Whole counties
County Brown County, IL
The radar
The Lincoln radar (KILX), 122 km from the middle of the area, began a volume at 05:44 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 nearest sounding before it
Lincoln, IL (KILX), launched 00:00Z, 5.7 hours before the alert went out and 184 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1165 m above ground
- 0-6 km bulk shear
- 68 kt
- 0-1 km storm-relative helicity
- 347 m²/s²
- 0-3 km storm-relative helicity
- 657 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
999 WUUS1 KSTL 210541 RRA SVRSTL ILC009-210615- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE ST LOUIS MO 1240 AM CDT WED APR 21 1999 THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... BROWN COUNTY IN WEST CENTRAL ILLINOIS * UNTIL 115 AM CDT * AT 1239 AM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM ABOUT 5 MILES WEST OF MOUNT STERLING... MOVING EAST AT 30 MPH. * LOCATIONS THAT WILL BE AFFECTED... MT STERLING BUCKHORN HERSMAN THE PRIMARY SEVERE WEATHER THREAT IS DAMAGING HAIL. LARGE HAIL CAN CAUSE EXTENSIVE PROPERTY DAMAGE AN SERIOUS INJURY TO PEOPLE CAUGHT OUTDOORS. MOVE INSIDE A STURDY BUILDING IMMEDIATELY. BRITT/TRUETT
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, Apr 20, 8:15 PM CDT, 4 hours 25 minutes before
ILZ058>060-064-065-069-070-074-079-095>102-MOZ009-010-018-019-026- 027-034>036-041-042-047>052-059>065-072>075-084-085-099-210700- SEVERE WEATHER OUTLOOK NATIONAL WEATHER SERVICE ST LOUIS MO 815 PM CDT TUE APR 20 1999 THIS OUTLOOK COVERS THE COUNTY WARNING AREA OF THE NWS OFFICE IN ST. LOUIS. AREAS INCLUDED ARE PARTS OF CENTRAL...NORTHEAST AND EAST CENTRAL MISSOURI...AND SOUTHWEST ILLINOIS. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER ALL OF THE COUNTY WARNING AREA TONIGHT. ALTHOUGH THE WEATHER WAS TRANQUIL ACROSS THE AREA EARLY THIS EVENING...THE LATEST WEATHER DATA INDICATES THAT THUNDERSTORMS WILL BE DEVELOPING ACROSS THE REGION AS THE NIGHT PROGRESSES...AND THERE IS A CHANCE THAT SOME OF THESE STORMS MAY BECOME SEVERE. SEVERE WEATHER SPOTTERS SHOULD MONITOR LATEST FORECASTS AND OUTLOOKS AS SKYWARN ACTIVATION MAY BE REQUIRED LATE THIS EVENING...AND DURING THE PREDAWN HOURS. TRUETT
Special weather statement, Apr 20, 8:15 PM CDT, 4 hours 25 minutes before
ILZ058>060-064-065-069-070-074-079-095>102-MOZ009-010-018-019-026- 027-034>036-041-042-047>052-059>065-072>075-084-085-099-210700- SEVERE WEATHER OUTLOOK NATIONAL WEATHER SERVICE ST LOUIS MO 815 PM CDT TUE APR 20 1999 THIS OUTLOOK COVERS THE COUNTY WARNING AREA OF THE NWS OFFICE IN ST. LOUIS. AREAS INCLUDED ARE PARTS OF CENTRAL...NORTHEAST AND EAST CENTRAL MISSOURI...AND SOUTHWEST ILLINOIS. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER ALL OF THE COUNTY WARNING AREA TONIGHT. ALTHOUGH THE WEATHER WAS TRANQUIL ACROSS THE AREA EARLY THIS EVENING...THE LATEST WEATHER DATA INDICATES THAT THUNDERSTORMS WILL BE DEVELOPING ACROSS THE REGION AS THE NIGHT PROGRESSES...AND THERE IS A CHANCE THAT SOME OF THESE STORMS MAY BECOME SEVERE. SEVERE WEATHER SPOTTERS SHOULD MONITOR LATEST FORECASTS AND OUTLOOKS AS SKYWARN ACTIVATION MAY BE REQUIRED LATE THIS EVENING...AND DURING THE PREDAWN HOURS. TRUETT
The office that day
Everything else NWS St. Louis, MO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 20, 11:56 PM CDT | Severe Thunderstorm Warning | LSX | Calhoun, Pike | 49 min |
Nearby
Severe Thunderstorm Warnings in Illinois, 1999Every severe thunderstorm warning in 1999
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.