Alert archive / Missouri / Tornado Watches in 2002

Tornado Watch 159

April 27, 200214 counties in Illinois; 55 counties in Missouri

The Storm Prediction Center issued this tornado watch at Apr 27, 2002, 6:30 PM CDT for 14 counties in Illinois; 55 counties in Missouri. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Apr 27, 2002, 6:30 PM CDT (23:30 UTC)
Expired
Apr 28, 2002, 12:00 AM CDT
In force
6 hr
Issued by
the Storm Prediction Center
All 69 counties

Adams County, IL, Brown County, IL, Calhoun County, IL, Cass County, IL, Fulton County, IL, Greene County, IL, Hancock County, IL, Jersey County, IL, McDonough County, IL, Monroe County, IL, Morgan County, IL, Pike County, IL, Schuyler County, IL, Scott County, IL, Adair County, MO, 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, Crawford County, MO, Dallas County, MO, Dent County, MO, Franklin County, MO, Gasconade County, MO, Greene County, MO, Henry County, MO, Hickory County, MO, Howard County, MO, Jefferson County, MO, Johnson County, MO, Knox County, MO, Laclede County, MO, Lafayette County, MO, Lewis County, MO, Lincoln County, MO, Linn County, MO, Livingston County, MO, Macon 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, Phelps County, MO, Pike County, MO, Polk County, MO, Pulaski County, MO, Ralls County, MO, Randolph County, MO, Saint Charles County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Saline County, MO, Shelby County, MO, St. Clair County, MO, Warren County, MO, Washington County, MO, Webster County, MO

The radar

The St Louis radar (KLSX), 149 km from the middle of the area, began a volume at 23:30 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

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

IssuedProductOfficeCountiesLasted
Apr 27, 6:53 PM CDTTornado WarningEAXLinn37 min
Apr 27, 7:11 PM CDTSevere Thunderstorm WarningEAXAdair, Sullivan49 min
Apr 27, 8:00 PM CDTTornado WarningLSXCallaway45 min
Apr 27, 8:17 PM CDTTornado WarningLSXMontgomery, Warren43 min
Apr 27, 8:38 PM CDTSevere Thunderstorm WarningDVNHancock52 min
Apr 27, 10:19 PM CDTSevere Thunderstorm WarningILXFulton, Peoria41 min

The nearest sounding before it

Springfield, MO (KSGF), launched 12:00Z, 11.5 hours before the alert went out and 278 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 2002-04-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Springfield, MO at 12:00Z on 2002-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 458 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
456 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
458 m²/s²
0-3 km storm-relative helicity
535 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.3

Open this sounding in Storm Lab

The text

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

000
WWUS20 KWNS 272312
SEL9  
SPC WW 272306
ILZ000-MOZ000-280500-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 159
STORM PREDICTION CENTER NORMAN OK
606 PM CDT SAT APR 27 2002

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

   WESTERN ILLINOIS                           
   CENTRAL AND EASTERN MISSOURI                           

EFFECTIVE THIS SATURDAY NIGHT AND SUNDAY MORNING FROM 630 PM UNTIL
MIDNIGHT CDT.

 ...THIS IS A PARTICULARLY DANGEROUS SITUATION...
 
DAMAGING TORNADOES...LARGE 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 100 STATUTE MILES NORTH AND
SOUTH OF A LINE FROM 20 MILES SOUTHWEST OF KNOB NOSTER MISSOURI TO
40 MILES NORTH NORTHEAST OF SAINT LOUIS MISSOURI.

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.

OTHER WATCH INFORMATION...THIS TORNADO WATCH REPLACES TORNADO WATCH
NUMBER 157.  WATCH NUMBER 157 WILL NOT BE IN EFFECT AFTER 630 PM
CDT.  CONTINUE...WW 158...

DISCUSSION...ISOLATED THUNDERSTORMS ARE SLOWLY INTENSIFYING OVER
PARTS OF WESTERN MO ALONG/AHEAD OF SURFACE DRYLINE.  EXTREMELY
STRONG SHEAR PROFILES...RAPID AIRMASS DESTABILIZATION...AND STRONG
SURFACE PRESSURE FALLS SUGGEST THE POTENTIAL FOR THESE STORMS TO
BECOME TORNADIC SUPERCELLS IN THE NEXT 1-3 HOURS.  SIGNIFICANT
TORNAODES APPEAR POSSIBLE IN THIS REGION.  VERY STRONG WINDS ALOFT
AND DRY MID LEVEL AIRMASS ALSO SUGGEST POTENTIAL FOR DAMAGING WINDS
AND LARGE HAIL.

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 450. 
MEAN STORM MOTION VECTOR 24045.

...HART

375,0900 370,0934 395,0934 404,0900

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 27, 3:00 PM CDTTornado WatchSPCBates, Benton, Buchanan, Caldwell, Carroll, Cass and 12 more5 hr
Apr 27, 3:30 PM CDTTornado WatchSPCAdair, Andrew, Atchison, Daviess, DeKalb, Gentry and 9 more5 hr

Nearby

Tornado Watches in Missouri, 2002Tornado Watches in Illinois, 2002Every tornado 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.