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WWUS20 KWNS 230137

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URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 77

NWS STORM PREDICTION CENTER NORMAN OK

830 PM CDT THU APR 22 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       WESTERN AND NORTH CENTRAL OKLAHOMA

       NORTHWEST TEXAS AND THE TEXAS SOUTH PLAINS



EFFECTIVE THIS THURSDAY NIGHT AND FRIDAY MORNING FROM 830 PM

UNTIL 400 AM CDT.



TORNADOES...HAIL TO 2.5 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 90 STATUTE

MILES EAST AND WEST OF A LINE FROM 25 MILES NORTHEAST OF ALVA

OKLAHOMA TO 10 MILES SOUTH OF BIG SPRING TEXAS.  FOR A COMPLETE

DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE

(WOUS64 KWNS WOU7).



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 75. WATCH NUMBER 75 WILL NOT BE IN EFFECT AFTER 830

PM CDT. CONTINUE...WW 74...WW 76...



DISCUSSION...SUPERCELLS...SOME LONG-LIVED AND VERY STRONG...EXPECTED

TO PERSIST THROUGH EARLY FRI OVER PARTS OF THE TX SOUTH PLAINS AND

NW TX/FAR SW OK AS SSWLY LLJ STRENGTHENS AND FURTHER MOISTENS AHEAD

OF NM UPR IMPULSE.  STRENGTH OF MEAN WIND FIELD...INCREASING LOW-LVL

MOISTURE ...AND BACKED LOW-LVL FLOW SUGGEST CONTINUED LIKELIHOOD FOR

TORNADOES WITH SOME STORMS...IN ADDITION TO VERY LARGE HAIL AND DMGG

WINDS.  FARTHER N...SEMI-DISCRETE STORMS/SUPERCELLS ALSO EXPECTED TO

PERSIST IN SOMEWHAT MORE STRONGLY CAPPED BUT CONFLUENT ENVIRONMENT

IN WRN/NRN OK.  THIS ACTIVITY ALSO COULD POSE A RISK FOR TORNADOES

AS STORMS EVOLVE INTO LOOSELY-ORGANIZED/EPISODIC LEWPS.



AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

550. MEAN STORM MOTION VECTOR 24030.





...CORFIDI

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