Alert archive / Illinois / Severe Thunderstorm Watches in 2002

Severe Thunderstorm Watch 293

May 12, 20024 states

The Storm Prediction Center issued this severe thunderstorm watch at May 12, 2002, 6:15 PM CDT for 4 states. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: May 12, 2002, 6:15 PM CDT (23:15 UTC)
Expired: May 12, 2002, 11:00 PM CDT
In force: 5 hr
Issued by: the Storm Prediction Center

All 37 counties

Clay County, IL, Clinton County, IL, Edwards County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Jackson County, IL, Jefferson County, IL, Lawrence County, IL, Marion County, IL, Monroe County, IL, Perry County, IL, Randolph County, IL, Richland County, IL, Saint Clair County, IL, Saline County, IL, Union County, IL, Wabash County, IL, Washington County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Gibson County, IN, Posey County, IN, Vanderburgh County, IN, Union County, KY, Bollinger County, MO, Cape Girardeau County, MO, Franklin County, MO, Iron County, MO, Jefferson County, MO, Madison County, MO, Perry County, MO, Reynolds County, MO, Saint Francois County, MO, Sainte Genevieve County, MO, Washington County, MO

The radar

The St Louis radar (KLSX), 104 km from the middle of the area, began a volume at 23:17 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.

Warnings issued inside it

11 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
May 12, 6:42 PM CDT	Severe Thunderstorm Warning	PAH	Perry	48 min
May 12, 6:44 PM CDT	Tornado Warning	LSX	Randolph	46 min
May 12, 7:08 PM CDT	Severe Thunderstorm Warning	PAH	Jackson	67 min
May 12, 7:24 PM CDT	Severe Thunderstorm Warning	PAH	Perry	51 min
May 12, 7:37 PM CDT	Severe Thunderstorm Warning	PAH	Franklin, Williamson	68 min
May 12, 7:40 PM CDT	Flash Flood Warning	LSX	Randolph	6 hr
May 12, 8:08 PM CDT	Flash Flood Warning	LSX	Bond, Calhoun, Clinton, Fayette, Greene, Jersey and 7 more	6 hr
May 12, 8:08 PM CDT	Flash Flood Warning	PAH	Franklin, Jackson, Jefferson, Johnson, Perry, Union and 1 more	6 hr
May 12, 9:19 PM CDT	Flash Flood Warning	LSX	Bond, Calhoun, Clinton, Fayette, Greene, Jersey and 7 more	5 hr
May 12, 10:15 PM CDT	Flash Flood Warning	PAH	Gibson, Pike	4 hr
May 12, 10:41 PM CDT	Flash Flood Warning	PAH	Edwards, Wabash, Wayne	3 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 11.3 hours before the alert went out and 245 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: 77 J/kg
Mixed-layer CIN: -142 J/kg
Mixed-layer LCL: 829 m above ground
0-6 km bulk shear: 75 kt
0-1 km storm-relative helicity: 163 m²/s²
0-3 km storm-relative helicity: -16 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

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

000 
WWUS20 KWNS 122306
SEL3  
SPC WW 122303
ILZ000-INZ000-MOZ000-130400-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 293
STORM PREDICTION CENTER NORMAN OK
603 PM CDT SUN MAY 12 2002

THE STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

   SOUTHERN ILLINOIS                           
   SOUTHWEST INDIANA                            
   EAST CENTRAL AND SOUTHEAST MISSOURI                           

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 615 PM UNTIL 1100
PM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 45 STATUTE MILES
NORTH AND SOUTH OF A LINE FROM 105 MILES WEST OF CARBONDALE
ILLINOIS TO 70 MILES EAST OF MOUNT VERNON ILLINOIS.

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. 
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.  SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE
TORNADOES.

OTHER WATCH INFORMATION...THIS SEVERE THUNDERSTORM WATCH REPLACES
SEVERE THUNDERSTORM WATCH NUMBER 290.  WATCH NUMBER 290 WILL NOT BE
IN EFFECT AFTER 615 PM CDT.  CONTINUE...WW 288...WW 289...WW
291...WW 292...

DISCUSSION...MOIST/UNSTABLE AIRMASS REMAINS OVER SOUTHEAST MO AND
SOUTHERN IL...AHEAD OF LARGE CLUSTER OF STORMS OVER CENTRAL MO. 
THESE STORMS SHOULD TRACK EASTWARD FOR NEXT SEVERAL HOURS...WITH
THE THREAT OF DAMAGING WINDS AND LARGE HAIL.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.  MEAN STORM
MOTION VECTOR 26035.

...HART

382,0911 385,0873 373,0873 370,0911

WWUS20 KWNS 122306
SEL3  
SPC WW 122303
ILZ000-INZ000-MOZ000-130400-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 293
STORM PREDICTION CENTER NORMAN OK
603 PM CDT SUN MAY 12 2002

THE STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

   SOUTHERN ILLINOIS                           
   SOUTHWEST INDIANA                            
   EAST CENTRAL AND SOUTHEAST MISSOURI                           

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 615 PM UNTIL 1100
PM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 45 STATUTE MILES
NORTH AND SOUTH OF A LINE FROM 105 MILES WEST OF CARBONDALE
ILLINOIS TO 70 MILES EAST OF MOUNT VERNON ILLINOIS.

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. 
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.  SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE
TORNADOES.

OTHER WATCH INFORMATION...THIS SEVERE THUNDERSTORM WATCH REPLACES
SEVERE THUNDERSTORM WATCH NUMBER 290.  WATCH NUMBER 290 WILL NOT BE
IN EFFECT AFTER 615 PM CDT.  CONTINUE...WW 288...WW 289...WW
291...WW 292...

DISCUSSION...MOIST/UNSTABLE AIRMASS REMAINS OVER SOUTHEAST MO AND
SOUTHERN IL...AHEAD OF LARGE CLUSTER OF STORMS OVER CENTRAL MO. 
THESE STORMS SHOULD TRACK EASTWARD FOR NEXT SEVERAL HOURS...WITH
THE THREAT OF DAMAGING WINDS AND LARGE HAIL.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.  MEAN STORM
MOTION VECTOR 26035.

...HART

382,0911 385,0873 373,0873 370,0911

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 12, 2:45 PM CDT	Severe Thunderstorm Watch	SPC	Bond, Calhoun, Christian, Clark, Clay, Clinton and 23 more	5 hr
May 11, 7:00 PM CDT	Tornado Watch	SPC	Atchison, Gentry, Grundy, Harrison, Holt, Mercer and 2 more	5 hr
May 12, 12:30 AM CDT	Severe Thunderstorm Watch	SPC	Barton, Bates, Henry, Jasper, St. Clair, Vernon	6 hr
May 12, 1:15 PM CDT	Severe Thunderstorm Watch	SPC	Barry, Barton, Camden, Cedar, Christian, Dade and 17 more	6 hr

Nearby

Severe Thunderstorm Watches in Illinois, 2002 Severe Thunderstorm Watches in Missouri, 2002 Severe Thunderstorm Watches in Indiana, 2002 Every severe thunderstorm watch in 2002

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.