

000 

WWUS20 KWNS 222348

SEL8

SPC WW 222348

COZ000-KSZ000-230500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 638

NWS STORM PREDICTION CENTER NORMAN OK

550 PM MDT WED AUG 22 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EASTERN COLORADO

       WESTERN KANSAS



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 550 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 50

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 10 MILES NORTH

NORTHWEST OF COLORADO SPRINGS COLORADO TO 40 MILES SOUTHEAST OF

GOODLAND KANSAS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).



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 637...



DISCUSSION...THUNDERSTORMS WILL INCREASE IN COVERAGE/INTENSITY ALONG

E-W BOUNDARY NEAR I-70.  CONVECTION MAY GROW INTO ONE OR MORE

CLUSTERS LATER THIS EVENING IN ADVANCE OF A MID LEVEL WAVE EJECTING

EWD/ENEWD FROM SW CO.  INSTABILITY AND DEEP LAYER VERTICAL SHEAR

WILL BE SUFFICIENT FOR STORMS WITH SUPERCELL STRUCTURES WITH THE

INITIAL STORMS...WHICH WILL LOCALLY ENHANCE THE THREAT FOR LARGE

HAIL.  DAMAGING WINDS WILL ALSO BE A THREAT...ESPECIALLY AS STORM

MERGERS PROMOTE COLD POOL DEVELOPMENT.



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 500. MEAN STORM

MOTION VECTOR 27020.





...THOMPSON

