

068 

WWUS20 KWNS 040039

SEL7

SPC WW 040039

TXZ000-040600-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 137

NWS STORM PREDICTION CENTER NORMAN OK

735 PM CDT TUE APR 3 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHEAST TEXAS



EFFECTIVE THIS TUESDAY NIGHT AND WEDNESDAY MORNING FROM 735 PM

UNTIL 100 AM CDT.



HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 55

STATUTE MILES EAST AND WEST OF A LINE FROM 25 MILES WEST

NORTHWEST OF LUFKIN TEXAS TO 85 MILES SOUTH SOUTHWEST OF COLLEGE

STATION TEXAS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).



REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE

FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY

DO PRODUCE TORNADOES.



OTHER WATCH INFORMATION...CONTINUE...WW 133...WW 134...WW

135...WW 136...



DISCUSSION...SEVERE STORMS ALONG A SLOW-MOVING DRYLINE/OUTFLOW

BOUNDARY WILL CONTINUE TO MOVE NEWD ALONG THE BAND...WHILE THE BAND

SAGS SLOWLY SEWD TONIGHT.  CONVECTIVE INHIBITION AND ONLY WEAK

LOW-LEVEL ASCENT MAKE THE SW EXTENT OF STORM DEVELOPMENT

UNCERTAIN...BUT 00Z REGIONAL SOUNDINGS SHOW MLCAPE OF 3000-4000 J/KG

AND A RELATIVELY DEEP/MOIST BOUNDARY LAYER FROM THE MIDDLE TX

COASTAL PLAIN NEWD INTO E/SE TX.  THE COMBINATION OF STRONG

INSTABILITY AND MODEST DEEP-LAYER VERTICAL SHEAR WILL SUPPORT BOTH

MULTICELL LINE SEGMENTS/CLUSTER...AND PERHAPS SOME EMBEDDED

SUPERCELL STRUCTURES...WITH AN ATTENDANT RISK FOR LARGE HAIL AND

DAMAGING WINDS.



AVIATION...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 25025.





...THOMPSON

