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WWUS20 KWNS 212207

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COZ000-KSZ000-NEZ000-220500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 512

NWS STORM PREDICTION CENTER NORMAN OK

505 PM CDT WED JUL 21 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHEAST COLORADO

       NORTHWEST AND NORTH-CENTRAL KANSAS

       SOUTHWEST AND SOUTH-CENTRAL NEBRASKA



EFFECTIVE THIS WEDNESDAY AFTERNOON FROM 505 PM UNTIL MIDNIGHT 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 65

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 45 MILES WEST

SOUTHWEST OF AKRON COLORADO TO 30 MILES SOUTH SOUTHEAST OF

HASTINGS NEBRASKA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).



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 507...WW 508...WW

509...WW 510...WW 511...



DISCUSSION...TSTMS SHOULD CONTINUE TO DEVELOP WITHIN MULTIPLE

FORCING REGIMES IN PLACE OVER THE REGION THIS EVENING.  NERN CO

STORMS WILL LIKELY BE DRIVEN BY A WEAK IMPULSE CRESTING MIDLEVEL

RIDGE AXIS...WITH DEVELOPING KS STORMS FORCED MORE SO BY LOW-LEVEL

CONVERGENCE AND STRONG DIABATIC HEATING.  AMBIENT AIR MASS IS RATHER

MOIST WITH MLCAPE RANGING FROM 1000-2000 J/KG ACROSS NERN CO TO

2000-3000+ J/KG ACROSS NRN KS/SRN NEB.  WHILE MID AND HIGH-LEVEL

WIND FIELD IS NOT PARTICULARLY STRONG...AREA VWPS/PROFILERS INDICATE

VERTICALLY-VEERING WINDS WITH 100-150 M2/S2 0-1 KM SRH AND AROUND 30

KT OF DEEP-LAYER BULK SHEAR.  GIVEN ENVIRONMENT WILL BE SUPPORTIVE

OF ORGANIZED STORMS INCLUDING SUPERCELLS.  WHILE A BRIEF TORNADO IS

POSSIBLE...THE PRIMARY HAZARDS APPEAR TO BE LARGE HAIL AND DAMAGING

WIND GUSTS.



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 27020.





...MEAD

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