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WWUS20 KWNS 131749

SEL0

SPC WW 131749

COZ000-NDZ000-NEZ000-SDZ000-140000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 70

NWS STORM PREDICTION CENTER NORMAN OK

1250 PM CDT TUE APR 13 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SMALL PART OF NORTHEAST COLORADO

       MUCH OF WESTERN AND PARTS OF CENTRAL NORTH DAKOTA

       MUCH OF WESTERN NEBRASKA

       MUCH OF WESTERN AND PARTS OF CENTRAL SOUTH DAKOTA



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 1250 PM UNTIL

700 PM CDT.



HAIL TO 1.5 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 EAST AND WEST OF A LINE FROM 10 MILES SOUTH

SOUTHWEST OF IMPERIAL NEBRASKA TO 15 MILES NORTH OF MINOT NORTH

DAKOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED

WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).



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.



DISCUSSION...STRONG COLD FRONT PUSHING EWD INTO HIGH PLAINS WILL BE

FOCUS FOR A DEVELOPING LINE OF STRONG/SEVERE THUNDERSTORMS THRU THE

AFTERNOON.  EVEN WITH ONLY MODEST INSTABILITY...STRENGTH OF WIND

FIELDS AND STEEP LOW/MID LEVEL LAPSE RATES SUPPORT DAMAGING WIND

THREAT AS THE LINE MOVES EWD ACROSS WATCH AREA.



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

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 400. MEAN STORM

MOTION VECTOR 22035.





...HALES

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