

688 

WWUS20 KWNS 300638

SEL6

SPC WW 300638

COZ000-KSZ000-NEZ000-301400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 216

NWS STORM PREDICTION CENTER NORMAN OK

1235 AM MDT THU APR 30 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHEAST COLORADO

       NORTHWEST KANSAS

       SOUTHWEST NEBRASKA



EFFECTIVE THIS THURSDAY MORNING FROM 1235 AM UNTIL 800 AM MDT.



HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 60

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



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 90

STATUTE MILES EAST AND WEST OF A LINE FROM 35 MILES NORTHWEST OF

MCCOOK NEBRASKA TO 55 MILES SOUTH OF MCCOOK NEBRASKA.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU6).



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 215...



DISCUSSION...TSTMS HAVE FORMED IN THE PAST 2 HRS ALONG COLD FRONT

MOVING SE ACROSS THE CNTRL HI PLNS.  ADDITIONAL STORMS EXPECTED TO

FORM ALONG FRONT THROUGH LATER THIS MORNING GIVEN CONSIDERABLE DEPTH

OF BOUNDARY AND INCREASINGLY MOIST SSELY LOW LVL FLOW DIRECTED INTO

IT.  WHILE DEEP SHEAR WILL BE MODEST...COMBINATION OF STEEP MID LVL

LAPSE RATES AND FORCED ASCENT OF MOIST AIR AT FRONT MAY SUPPORT SCTD

SVR HAIL.



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

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 50

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM

MOTION VECTOR 28025.





...CORFIDI

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