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849 

WWUS20 KWNS 241943

SEL1

SPC WW 241943

COZ000-NEZ000-WYZ000-250300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 441

NWS STORM PREDICTION CENTER NORMAN OK

140 PM MDT WED JUL 24 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  NORTHEASTERN COLORADO

  WESTERN AND NORTHERN NEBRASKA

  SOUTHEASTERN WYOMING



* EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 140 PM

  UNTIL 900 PM MDT.



* PRIMARY THREATS INCLUDE...

  SEVERAL VERY LARGE HAIL EVENTS TO 2.5 INCHES IN DIAMETER

    POSSIBLE

  SEVERAL DAMAGING WIND GUSTS WITH A FEW SIGNIFICANT GUSTS TO 75

    MPH POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 135

STATUTE MILES EAST AND WEST OF A LINE FROM 35 MILES EAST

SOUTHEAST OF AKRON COLORADO TO 60 MILES NORTH NORTHWEST OF MULLEN

NEBRASKA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).



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...SVR THREAT IS RAMPING UP ACROSS THIS REGION WITH

INCREASING CONVECTIVE COVERAGE...IN ENVIRONMENT FAVORABLE FOR

SLOW-MOVING SUPERCELLS...WITH LARGE HAIL AND OCNL STG-SVR GUSTS.

LOW-LEVEL CONVERGENCE WILL REMAIN JUXTAPOSED WITH SUFFICIENT

MOISTURE AND LAPSE RATES TO SUPPORT 2000-3000 J/KG PRECONVECTIVE

MLCAPE.  DEEP-LAYER SHEAR STRENGTHENS WITH NEWD EXTENT...WITH

EFFECTIVE SHEAR PEAKING AROUND 50-55 KT OVER NRN NEB.  SOME

AGGREGATED/UPSCALE GROWTH AND FORWARD PROPAGATION IS POSSIBLE AS

WELL...IN WHICH CASE DAMAGING WIND THREAT WOULD BECOME BETTER

ORGANIZED.



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

TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 65

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 32015.





...EDWARDS

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