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998 

WWUS20 KWNS 262040

SEL7

SPC WW 262040

ARZ000-LAZ000-OKZ000-TXZ000-270400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 447

NWS STORM PREDICTION CENTER NORMAN OK

340 PM CDT FRI JUL 26 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  EXTREME SOUTHWESTERN ARKANSAS

  NORTHWESTERN LOUISIANA

  SMALL PART OF SOUTHERN OKLAHOMA

  NORTH-CENTRAL AND NORTHEAST TEXAS



* EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 340 PM UNTIL

  1100 PM CDT.



* PRIMARY THREATS INCLUDE...

  SEVERAL DAMAGING WIND GUSTS WITH A FEW SIGNIFICANT GUSTS TO 75

    MPH POSSIBLE

  SEVERAL LARGE HAIL EVENTS WITH A FEW VERY LARGE HAIL EVENTS TO 2

    INCHES IN DIAMETER POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 55

STATUTE MILES EITHER SIDE OF A LINE FROM 30 MILES SOUTH SOUTHWEST

OF SHERMAN TEXAS TO 20 MILES EAST NORTHEAST OF SHREVEPORT

LOUISIANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).



PRECAUTIONARY/PREPAREDNESS ACTIONS...



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.



&&



DISCUSSION...TSTMS FCST TO EXPAND IN COVERAGE AND INCREASE IN

INTENSITY DURING REMAINDER AFTERNOON.  MULTICELL CLUSTERS AND A

COUPLE OF SUPERCELLS ARE POSSIBLE...OFFERING MOSTLY DAMAGING GUSTS

AND OCNL HAIL.  A TORNADO CANNOT BE RULED OUT...MAINLY INVOF

QUASISTATIONARY OUTFLOW/DIFFERENTIAL HEATING-BOUNDARY ARCHING FROM

LAKE TEXOMA AREA SEWD TO NEAR SHV.  AIR MASS NEAR THAT BOUNDARY WILL

BE CHARACTERIZED BY SLY/SELY SFC FLOW...MAXIMIZING LOW-LEVEL

STORM-RELATIVE INFLOW AND DEEP BULK SHEAR.  AIR MASS BETWEEN THAT

BOUNDARY AND COLD FRONT NOW APCHG METROPLEX WILL BE CHARACTERIZED BY

2000-3000 J/KG MLCAPE AND 35-50 KT EFFECTIVE SHEAR MAGNITUDES.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 65

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM

MOTION VECTOR 30025.





...EDWARDS

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