

615 

WWUS20 KWNS 082149

SEL2

SPC WW 082149

COZ000-KSZ000-NEZ000-SDZ000-090500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 612

NWS STORM PREDICTION CENTER NORMAN OK

350 PM MDT FRI JUL 8 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHEAST COLORADO

       NORTHWEST KANSAS

       WESTERN NEBRASKA INCLUDING THE PANHANDLE

       WESTERN AND CENTRAL SOUTH DAKOTA



EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 350 PM UNTIL

1100 PM MDT.



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 80

STATUTE MILES EAST AND WEST OF A LINE FROM 15 MILES NORTHWEST OF

LEMMON SOUTH DAKOTA TO 40 MILES SOUTH SOUTHWEST OF BURLINGTON

COLORADO.  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 610...WW 611...



DISCUSSION...MULTIPLE CLUSTERS OF SEVERE TSTMS ARE EXPECTED TO

EVOLVE THIS EVENING AS ONGOING STORMS MOVE/DEVELOP EWD INTO A

MODERATELY UNSTABLE AIR MASS WHERE MLCAPE HAS INCREASED TO 2000-3000

J/KG.  AREA VAD/PROFILER DATA SHOW THE PRESENCE OF 25-35 KT WSWLY

MIDLEVEL FLOW ATOP SELY BOUNDARY-LAYER WINDS...RESULTING IN

SUFFICIENT VERTICAL SHEAR FOR ORGANIZED MULTICELLS AND SUPERCELLS.

LARGE HAIL WILL BE THE PRIMARY HAZARD OVER THE HIGH PLAINS THIS

EVENING WITH THE DAMAGING WIND THREAT INCREASING THIS EVENING INTO

TONIGHT AS STORMS COALESCE INTO LARGE CLUSTERS AND GROW COLD POOLS.



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 27030.





...MEAD

