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WWUS20 KWNS 062031

SEL4

SPC WW 062031

COZ000-KSZ000-NEZ000-WYZ000-070300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 274

NWS STORM PREDICTION CENTER NORMAN OK

225 PM MDT SUN JUN 6 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHEASTERN COLORADO

       EXTREME NORTHWESTERN KANSAS

       WESTERN NEBRASKA

       SOUTHEASTERN WYOMING



EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 225 PM UNTIL 900

PM MDT.



HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 85

STATUTE MILES EITHER SIDE OF A LINE FROM 25 MILES NORTHEAST OF

IMPERIAL NEBRASKA TO 30 MILES NORTH NORTHWEST OF FORT COLLINS

COLORADO.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



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 272...WW 273...



DISCUSSION...STORMS HAD RECENTLY DEVELOPED OVER THE HIGHER TERRAIN

OF SRN WY AND PORTIONS OF NRN CO. THESE STORMS ARE EXPECTED TO

GRADUALLY DEVELOP/SPREAD EWD INTO THE PLAINS WHERE MUCAPES FROM

2000-2500 J/KG AND 50 TO 60 KT OF DEEP LAYER SHEAR WILL BE

SUFFICIENT FOR SUPERCELLS. STEEP MID LEVEL LAPSE RATES AND STORM

ROTATION SHOULD BE FAVORABLE FOR LARGE HAIL. ALSO...STEEP LOW LEVEL

LAPSE RATES WILL SUPPORT A DAMAGING WIND THREAT. AN ISOLATED TORNADO

IS ALSO POSSIBLE...BUT THE RELATIVELY DRY BOUNDARY LAYER AND WEAK

WINDS/SHEAR IN THE LOWER 1 KM SHOULD KEEP THEM BRIEF.



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

TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70

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

MOTION VECTOR 31025.





...IMY

