Tornado Watch 334

Issued

May 22, 2011, 8:26 PM CDT (01:26 UTC)

Expired

May 23, 2011, 4:00 AM CDT

In force

8 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

The St Louis radar (KLSX), 38 km from the middle of the area, began a volume at 01:26 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.

Two or more tornadoes

50%

One or more EF2 to EF5 tornadoes

20%

Ten or more severe wind reports

60%

One or more gusts of 65 knots or more

40%

Ten or more severe hail reports

40%

One or more hailstones of 2 inches or more

30%

Six or more combined severe hail and wind reports

95%

• Mesoscale Discussion 866May 22, 5:47 PM CDT
• Mesoscale Discussion 867May 22, 6:10 PM CDT
• Mesoscale Discussion 874May 22, 7:52 PM CDT
• Mesoscale Discussion 879May 22, 10:24 PM CDT

166 
WWUS20 KWNS 230128
SEL4
SPC WW 230128
ILZ000-MOZ000-230900-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 334
NWS STORM PREDICTION CENTER NORMAN OK
825 PM CDT SUN MAY 22 2011

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

       CENTRAL AND SOUTHWEST ILLINOIS
       EASTERN AND SOUTHERN MISSOURI

EFFECTIVE THIS SUNDAY NIGHT AND MONDAY MORNING FROM 825 PM UNTIL
400 AM CDT.

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 APPROXIMATELY ALONG AND 75 STATUTE
MILES EAST AND WEST OF A LINE FROM 30 MILES NORTH OF CHAMPAIGN
ILLINOIS TO 45 MILES WEST SOUTHWEST OF WEST PLAINS MISSOURI.  FOR
A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU4).

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 323...WW 325...WW
326...WW 327...WW 329...WW 330...WW 332...WW 333...

DISCUSSION...EARLIER SUPERCELLS ARE NOW MERGING INTO TWO MCS/S...ONE
NEAR STL...AND ANOTHER ALONG THE SW MO/NW AR BORDER.  MODERATE
INSTABILITY IS STILL PRESENT IN A CORRIDOR IN ADVANCE OF THIS
CONVECTION...W OF A MORE STABLE AIR MASS OVER SRN IL/WRN KY.  GIVEN
THE ORGANIZED CONVECTIVE STRUCTURES...INCLUDING BOWS AND
SUPERCELLS...AND SUFFICIENT LOW-LEVEL AND DEEP-LAYER SHEAR TO
MAINTAIN THESE STORM TYPES...A RISK FOR TORNADOES...DAMAGING
WINDS...AND LARGE HAIL WILL PERSIST.  THE MORE PERSISTENT TORNADO
THREAT IS EXPECTED ACROSS SRN MO INVOF OF A RETREATING OUTFLOW
BOUNDARY NEAR THE MO/AR BORDER.

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
550. MEAN STORM MOTION VECTOR 28035.


...THOMPSON

Tornado Watches in Illinois, 2011Tornado Watches in Missouri, 2011Every tornado watch in 2011

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.