Alert archive / Illinois / Severe Thunderstorm Warnings in 1994

Severe Thunderstorm Warning 89, NWS Lincoln, IL

August 18, 1994Boone County, Winnebago County, Illinois

NWS Lincoln, IL issued this severe thunderstorm warning at Aug 18, 1994, 11:21 PM CDT for Boone County, Winnebago County, Illinois. It was in force for 40 min.

The area

The counties it named.

The facts

Issued: Aug 18, 1994, 11:21 PM CDT (04:21 UTC)
Expired: Aug 19, 1994, 12:01 AM CDT
In force: 40 min
Issued by: NWS Lincoln, IL
Area: Whole counties

Counties Boone County, IL, Winnebago County, IL

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 00:00Z, 4.4 hours before the alert went out and 250 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 7 J/kg
Mixed-layer CIN: -66 J/kg
Mixed-layer LCL: 600 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 35 m²/s²
0-3 km storm-relative helicity: 70 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WUUS1 KRFD 190421 RRA
SVRRFD
ILC201-007-190515-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING 
NATIONAL WEATHER SERVICE ROCKFORD IL
1121 PM CDT THU AUG 18 1994

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM 
WARNING EFFECTIVE UNTIL 1215 AM CDT FOR PEOPLE IN THE FOLLOWING 
COUNTIES

   IN THE NORTH CENTRAL PART OF ILLINOIS
      EASTERN WINNEBAGO...BOONE

AT 1115 PM CDT 3/4 INCH TO 1 INCH SIZE HAIL WAS REPORTED IN THE
CITY OF ROCKFORD. THE STORM PRODUCING THIS HAIL MOVING TO THE EAST
AT 20 MPH.

SOME COMMUNITIES THAT WILL BE AFFECTED BY THIS SEVERE THUNDERSTORM...
GREATER ROCKFORD METRO AREA...BELVIDERE

IF YOU ARE IN THE PATH OF THIS STORM...MOVE OUT OF AREAS THAT ARE
PRONE TO FLOODING AND TAKE SHELTER.  DAMAGING WINDS...LARGE HAIL
AND VERY HEAVY RAIN IS IMMINENT! REMEMBER...SEVERE THUNDERSTORMS
CAN ALSO PRODUCE TORNADOES WITH LITTLE OR NO WARNING!

REHWALD

The office that day

Everything else NWS Lincoln, IL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 18, 9:30 PM CDT	Severe Thunderstorm Warning	ILX	Boone, DeKalb, Ogle, Winnebago	45 min
Aug 19, 3:31 PM CDT	Severe Thunderstorm Warning	ILX	Stephenson	29 min
Aug 19, 4:08 PM CDT	Severe Thunderstorm Warning	ILX	Winnebago	52 min
Aug 19, 4:08 PM CDT	Severe Thunderstorm Warning	ILX	Jo Daviess	52 min
Aug 19, 4:33 PM CDT	Tornado Warning	ILX	Stephenson, Winnebago	42 min
Aug 19, 5:16 PM CDT	Severe Thunderstorm Warning	ILX	Carroll, Ogle	44 min

Nearby

Severe Thunderstorm Warnings in Illinois, 1994 Every severe thunderstorm warning in 1994

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.