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WWUS20 KWNS 131832

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OKZ000-TXZ000-140200-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 160

NWS STORM PREDICTION CENTER NORMAN OK

130 PM CDT FRI APR 13 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       OKLAHOMA

       A SMALL PART OF NORTHWEST TEXAS



EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 130 PM UNTIL 900

PM CDT.



TORNADOES...HAIL TO 3 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 60 STATUTE

MILES EAST AND WEST OF A LINE FROM 35 MILES WEST OF WICHITA FALLS

TEXAS TO 20 MILES NORTH NORTHWEST OF PONCA CITY OKLAHOMA.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU0).



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.



DISCUSSION...STORMS ARE BEGINNING TO DEVELOP OVER SWRN OK AS THE CAP

HAS WEAKENED WITHIN A STRONGLY UNSTABLE ENVIRONMENT WITH MLCAPE OF

2000-2500 J/KG.  ALTHOUGH DYNAMIC FORCING FOR LARGE SCALE ASCENT IS

SUBTLE...NUMERICAL GUIDANCE INDICATES THAT STORMS WILL CONTINUE TO

DEVELOP TOWARD NRN OK THIS AFTERNOON...WITH CONVECTIVE POTENTIAL

ALSO INCREASING ALONG THE NWRN EDGE OF MOISTURE AS IT RETREATS NWWD

LATER THIS AFTERNOON AND EVENING.  DEEP LAYER SHEAR OF 40 KT IN THE

LOWEST 6 KM WILL FAVOR FORMATION OF SUPERCELL STRUCTURES...WITH AN

INITIAL THREAT FOR LARGE HAIL AND STRONG WIND GUSTS.  WITH

TIME...LOW LEVEL WINDS/SHEAR WILL STRENGTHEN WITH A SUBSEQUENT

INCREASE IN TORNADO POTENTIAL LATER THIS AFTERNOON AND EVENING.



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

SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE

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

550. MEAN STORM MOTION VECTOR 23025.





...WEISS

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