Tornado Watch 21

Issued

Feb 27, 2011, 2:46 PM CST (20:46 UTC)

Expired

Feb 27, 2011, 11:00 PM CST

In force

8 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

Two or more tornadoes

40%

One or more EF2 to EF5 tornadoes

20%

Ten or more severe wind reports

30%

One or more gusts of 65 knots or more

30%

Ten or more severe hail reports

50%

One or more hailstones of 2 inches or more

30%

Six or more combined severe hail and wind reports

70%

• Mesoscale Discussion 149Feb 27, 2:12 PM CST
• Mesoscale Discussion 153Feb 27, 5:49 PM CST
• Mesoscale Discussion 157Feb 27, 8:07 PM CST

878 
WWUS20 KWNS 272050
SEL1  
SPC WW 272050
KSZ000-OKZ000-280300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 21
NWS STORM PREDICTION CENTER NORMAN OK
250 PM CST SUN FEB 27 2011

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

       SMALL PART OF SOUTH CENTRAL AND SOUTHEAST KANSAS
       NORTH CENTRAL OKLAHOMA

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 250 PM UNTIL 900
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 APPROXIMATELY ALONG AND 40 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 35 MILES SOUTH SOUTHWEST OF
ALVA OKLAHOMA TO 25 MILES EAST SOUTHEAST OF CHANUTE KANSAS.  FOR
A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU1).

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 20...

DISCUSSION...VISIBLE IMAGERY SHOWS DEEPENING CUMULUS NEAR AND E OF
THE TRIPLE POINT ACROSS N CENTRAL OK.  A SEPARATE BAND OF HIGH-BASED
CUMULUS IN NW OK DEMARCATES THE STRONG DRY SURGE AND SUGGESTS AN
INCREASE IN LOW-LEVEL CONVERGENCE/ASCENT NEAR THE TRIPLE POINT IN
THE NEXT COUPLE OF HOURS.  NOW THAT SURFACE TEMPERATURES HAVE WARMED
INTO THE 70S...THE CAP IS WEAKENING AND THUNDERSTORM DEVELOPMENT
APPEARS PROBABLE BY 22-23Z.  STRONG DEEP-LAYER SHEAR AND MLCAPE
APPROACHING 1500 J/KG WILL SUPPORT SUPERCELLS CAPABLE OF PRODUCING
LARGE HAIL. A COUPLE OF TORNADOES WILL BE POSSIBLE GIVEN 0-1 KM SRH
AOA 200 M2/S2 AND THE POTENTIAL FOR STORMS TO MOVE NEAR/ALONG THE
SURFACE WARM FRONT THIS EVENING.

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 25040.


...THOMPSON

Tornado Watches in Oklahoma, 2011Tornado Watches in Kansas, 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.