Alert archive / Missouri / Tornado Watches in 2002

Tornado Watch 783

December 18, 20024 states

The Storm Prediction Center issued this tornado watch at Dec 18, 2002, 9:30 AM CST for 4 states. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Dec 18, 2002, 9:30 AM CST (15:30 UTC)
Expired
Dec 18, 2002, 3:00 PM CST
In force
6 hr
Issued by
the Storm Prediction Center
All 43 counties

Adams County, IL, Cherokee County, KS, Adair County, MO, Audrain County, MO, Barton County, MO, Benton County, MO, Boone County, MO, Callaway County, MO, Camden County, MO, Cedar County, MO, Chariton County, MO, Christian County, MO, Cole County, MO, Cooper County, MO, Dade County, MO, Dallas County, MO, Greene County, MO, Henry County, MO, Hickory County, MO, Howard County, MO, Jasper County, MO, Johnson County, MO, Knox County, MO, Lawrence County, MO, Lewis County, MO, Macon County, MO, Marion County, MO, Miller County, MO, Moniteau County, MO, Monroe County, MO, Morgan County, MO, Newton County, MO, Pettis County, MO, Polk County, MO, Ralls County, MO, Randolph County, MO, Saline County, MO, Shelby County, MO, St. Clair County, MO, Stone County, MO, Vernon County, MO, Craig County, OK, Ottawa County, OK

The radar

The Pleasant Hill radar (KEAX), 100 km from the middle of the area, began a volume at 15:30 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.

The nearest sounding before it

Springfield, MO (KSGF), launched 12:00Z, 3.5 hours before the alert went out and 144 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 2002-12-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 894 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 2002-12-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 425 square meters per square second.1939587897Sfc1 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
894 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
549 m above ground
0-6 km bulk shear
69 kt
0-1 km storm-relative helicity
425 m²/s²
0-3 km storm-relative helicity
449 m²/s²
Significant tornado parameter
2.4
Supercell composite
8.2

Open this sounding in Storm Lab

The text

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

000 
WWUS20 KWNS 181536
SEL3  
SPC WW 181530
ILZ000-KSZ000-MOZ000-182100-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 783
STORM PREDICTION CENTER NORMAN OK
930 AM CST WED DEC 18 2002

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

EXTREME WEST CENTRAL ILLINOIS                           
EXTREME SOUTHEAST KANSAS                             
SOUTHWEST...CENTRAL...AND NORTHEAST MISSOURI                      
 
EFFECTIVE THIS WEDNESDAY MORNING AND AFTERNOON FROM 930 AM UNTIL
300 PM CST.

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

THE TORNADO WATCH AREA IS ALONG AND 55 STATUTE MILES EAST AND WEST
OF A LINE FROM 25 MILES WEST SOUTHWEST OF MONETT MISSOURI TO 35
MILES NORTHWEST OF QUINCY 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.

OTHER WATCH INFORMATION...  CONTINUE...WW 782...

DISCUSSION...SEVERAL SHORT LINES OF CONVECTION HAVE FORMED ACROSS
CENTRAL/NE MO.  12Z SGF SOUNDING SHOWS NO CAP AND 1500 J/KG CAPE
ONCE SURFACE TEMPERATURES WARM TO THE LOWER 60S...THUS ADDITIONAL
STORMS COULD FORM ACROSS SW/CENTRAL MO IN THE NEXT FEW HOURS ALONG
AND E OF AN EWD MOVING COLD FRONT.  THOUGH LOW-LEVEL FLOW HAS
VEERED SOME THIS MORNING...INSTABILITY AND VERTICAL SHEAR REMAIN
FAVORABLE FOR SUPERCELLS WITH THE POSSIBILITY OF TORNADOES. 
OTHERWISE...LARGE HAIL AND DAMAGING WINDS WILL BE POSSIBLE THROUGH
EARLY-MID AFTERNOON. 


AVIATION...TORNADOES AND 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 450. 
MEAN STORM MOTION VECTOR 24045.


...THOMPSON

364,0951 401,0924 401,0903 364,0931

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 17, 10:40 PM CSTTornado WatchSPCCalhoun, Cass, Greene, Jersey, Macoupin, Madison and 7 more5 hr
Dec 18, 2:15 AM CSTSevere Thunderstorm WatchSPCAdams, Hancock, Henderson6 hr
Dec 18, 3:30 AM CSTTornado WatchSPCCalhoun, Greene, Jersey, Macoupin, Madison, Monroe and 3 more5 hr
Dec 18, 4:35 PM CSTTornado WatchSPCCalhoun, Cass, Christian, DeWitt, Greene, Jersey and 8 more5 hr
Dec 17, 7:35 PM CSTTornado WatchSPCCherokee5 hr
Dec 18, 7:20 AM CSTTornado WatchSPCChristian, Dent, Douglas, Howell, Iron, Laclede and 12 more6 hr
Dec 18, 2:30 PM CSTTornado WatchSPCButler, Carter, Dunklin, Howell, Mississippi, New Madrid and 4 more7 hr
Dec 18, 5:50 PM CSTTornado WatchSPCDunklin, Pemiscot3 hr
Dec 18, 1:10 PM CSTTornado WatchSPCMcCurtain8 hr

Nearby

Tornado Watches in Missouri, 2002Tornado Watches in Oklahoma, 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.