

661 

WWUS20 KWNS 132309

SEL1

SPC WW 132309

COZ000-140500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 641

NWS STORM PREDICTION CENTER NORMAN OK

510 PM MDT WED JUL 13 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL COLORADO



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 510 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 40

STATUTE MILES EAST AND WEST OF A LINE FROM 30 MILES NORTH OF FORT

COLLINS COLORADO TO 20 MILES SOUTH SOUTHEAST OF COLORADO SPRINGS

COLORADO.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).



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 638...WW 639...WW 640...



DISCUSSION...ISOLATED THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER THE

FRONT RANGE AND FOOTHILLS OF CENTRAL CO THIS EVENING AND SPREAD

EASTWARD INTO THE ADJACENT PLAINS.  EASTERLY UPSLOPE LOW LEVEL FLOW

AND HIGH CAPE VALUES WILL PROMOTE INTENSE CONVECTION...DESPITE WEAK

LARGE SCALE FORCING FOR ASCENT.  SHEAR PROFILES ARE ALSO FAVORABLE

FOR SUPERCELL STRUCTURES.



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 26025.





...HART

