Alert archive / Missouri / Tornado Watches in 2003

Tornado Watch 85

April 4, 200316 counties in Illinois; 34 counties in Missouri

The Storm Prediction Center issued this tornado watch at Apr 4, 2003, 12:05 PM CST for 16 counties in Illinois; 34 counties in Missouri. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Apr 4, 2003, 12:05 PM CST (18:05 UTC)
Expired
Apr 4, 2003, 5:00 PM CST
In force
5 hr
Issued by
the Storm Prediction Center
All 50 counties

Adams County, IL, Brown County, IL, Calhoun County, IL, Cass County, IL, Greene County, IL, Jersey County, IL, Macoupin County, IL, Madison County, IL, Mason County, IL, Menard County, IL, Morgan County, IL, Pike County, IL, Saint Clair County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Audrain County, MO, Benton County, MO, Boone County, MO, Callaway County, MO, Camden County, MO, Carroll County, MO, Chariton County, MO, City of Saint Louis, MO, Cole County, MO, Cooper County, MO, Dallas County, MO, Franklin County, MO, Gasconade County, MO, Hickory County, MO, Howard County, MO, Lincoln County, MO, Maries County, MO, Marion County, MO, Miller County, MO, Moniteau County, MO, Monroe County, MO, Montgomery County, MO, Morgan County, MO, Osage County, MO, Pettis County, MO, Pike County, MO, Polk County, MO, Ralls County, MO, Randolph County, MO, Saint Charles County, MO, Saint Louis County, MO, Saline County, MO, Shelby County, MO, Warren County, MO

The radar

The St Louis radar (KLSX), 125 km from the middle of the area, began a volume at 18:08 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.

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Springfield, MO (KSGF), launched 12:00Z, 6.1 hours before the alert went out and 291 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-pSkew-T log-p diagram, Springfield, MO at 12:00Z on 2003-04-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 722 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Springfield, MO at 12:00Z on 2003-04-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 383 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
722 J/kg
Mixed-layer CIN
-267 J/kg
Mixed-layer LCL
771 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
383 m²/s²
0-3 km storm-relative helicity
361 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 
WWUS20 KWNS 041802
SEL5
SPC WW 041805
ILZ000-MOZ000-042300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 85
STORM PREDICTION CENTER NORMAN OK
1205 PM CST FRI APR 4 2003

THE STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

   WEST CENTRAL ILLINOIS                           
   CENTRAL AND EASTERN MISSOURI                           

EFFECTIVE THIS FRIDAY AFTERNOON FROM 1205 PM UNTIL 500 PM CST.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS ALONG AND 70 STATUTE MILES NORTH AND
SOUTH OF A LINE FROM 20 MILES SOUTH SOUTHWEST OF KNOB NOSTER
MISSOURI TO 20 MILES SOUTH SOUTHEAST OF SPRINGFIELD ILLINOIS.

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND 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.

DISCUSSION...THUNDERSTORMS ARE EXPECTED TO RAPIDLY INTENSIFY OVER
CENTRAL MO DURING THE NEXT 1-2 HOURS AS STRONG UPPER JET APPROACHES
REGION.  MODERATE INSTABILITY AND STRONG DEEP LAYER VERTICAL SHEAR
PROFILES WILL LIKELY RESULT IN SUPERCELL STORMS CAPABLE OF LARGE
HAIL...DAMAGING WINDS...AND ISOLATED TORNADOES.  ACTIVITY WILL
LIKELY ORGANIZE INTO AN MCS BY LATE AFTERNOON...WITH DAMAGING WINDS
BECOMING THE MAIN THREAT.  

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 70 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. 
MEAN STORM MOTION VECTOR 24035.

...HART

392,0934 403,0893 383,0893 372,0934

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 4, 7:23 AM CSTMesoscale DiscussionSPCAdams, Bond, Brown, Calhoun, Cass, Champaign and 55 more97 min
Apr 4, 9:47 AM CSTMesoscale DiscussionSPCClark, Coles, Crawford, Cumberland, Douglas, Edgar and 9 more58 min
Apr 4, 11:10 AM CSTMesoscale DiscussionSPCBond, Calhoun, Cass, Champaign, Christian, Clinton and 24 more95 min
Apr 4, 1:12 PM CSTMesoscale DiscussionSPCBond, Brown, Calhoun, Cass, Champaign, Christian and 35 more93 min
Apr 4, 1:29 PM CSTMesoscale DiscussionSPCBureau, Cook, DeKalb, DuPage, Grundy, Kane and 8 more91 min
Apr 4, 2:35 PM CSTTornado WatchSPCBond, Champaign, Christian, Clark, Clay, Clinton and 26 more5 hr
Apr 4, 3:10 PM CSTMesoscale DiscussionSPCBond, Champaign, Christian, Clark, Coles, Cumberland and 25 more2 hr
Apr 4, 4:25 PM CSTTornado WatchSPCAlexander, Bond, Clay, Clinton, Edwards, Franklin and 24 more6 hr
Apr 4, 5:11 PM CSTMesoscale DiscussionSPCBond, Champaign, Christian, Clark, Clay, Clinton and 24 more2 hr
Apr 3, 8:39 PM CSTMesoscale DiscussionSPCAdair, Andrew, Atchison, Buchanan, Caldwell, Carroll and 20 more2 hr
Apr 3, 9:20 PM CSTSevere Thunderstorm WatchSPCAdair, Andrew, Atchison, Buchanan, Caldwell, Clay and 17 more6 hr
Apr 3, 11:44 PM CSTMesoscale DiscussionSPCAndrew, Atchison, Buchanan, Caldwell, Clinton, Daviess and 13 more2 hr
Apr 4, 1:47 AM CSTMesoscale DiscussionSPCAndrew, Atchison, Buchanan, Caldwell, Clinton, Daviess and 12 more88 min
Apr 4, 4:43 PM CSTMesoscale DiscussionSPCDunklin, Pemiscot3 hr

Nearby

Tornado Watches in Missouri, 2003Tornado Watches in Illinois, 2003Every tornado watch in 2003

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.