

917 

WWUS20 KWNS 180257

SEL3

SPC WW 180257

TXZ000-CWZ000-181000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 183

NWS STORM PREDICTION CENTER NORMAN OK

955 PM CDT MON MAY 17 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHERN AND SOUTHEAST TEXAS

       COASTAL WATERS



EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 955 PM UNTIL

500 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 70

STATUTE MILES EITHER SIDE OF A LINE FROM 70 MILES WEST OF COTULLA

TEXAS TO 30 MILES EAST SOUTHEAST OF HOUSTON TEXAS.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU3).



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 180...WW 181...WW 182...



DISCUSSION...EXTENSIVE OUTFLOW BOUNDARY SPREADING SOUTHWARD INTO

ZONE OF HIGH INSTABILITY /MLCAPE 2000-3000 J PER KG/ ACROSS SOUTHERN

AND SOUTHEASTERN TEXAS WILL CONTINUE TO PROVIDE THE FOCUS AND LIFT

NECESSARY FOR STRONG THUNDERSTORM DEVELOPMENT TONIGHT. WHILE

EFFECTIVE SHEAR ACROSS THE REGION REMAINS MARGINAL FOR MORE INTENSE

AND LONG-LIVED STORM UPDRAFTS...CELL MERGERS/COLLISIONS AND

CONTINUED RECHARGING OF THE COLD POOL WILL ALL CONTRIBUTE TO A

CONTINUING CHANCE FOR LOCALLY DAMAGING WINDS AND OCCASIONAL HAIL

GIVEN THE MAGNITUDE OF CAPE IN THE AREA. IT IS ALSO POSSIBLE THAT

STORMS DEVELOPING EAST FROM BIG BEND AREA MAY GROW UPSCALE AND

EVOLVE INTO FORWARD PROPAGATING MCS WITH INCREASING WIND POTENTIAL

AFTER MIDNIGHT.



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 33020.





...CARBIN

