

697 

WWUS20 KWNS 080250

SEL1

SPC WW 080250

COZ000-KSZ000-NEZ000-081000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 891

NWS STORM PREDICTION CENTER NORMAN OK

850 PM MDT SUN SEP 7 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHEAST COLORADO

       NORTHWEST KANSAS

       SOUTHWEST NEBRASKA



EFFECTIVE THIS SUNDAY NIGHT AND MONDAY MORNING FROM 850 PM UNTIL

400 AM MDT.



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 60

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 65 MILES WEST OF

AKRON COLORADO TO 40 MILES EAST OF HILL CITY KANSAS.  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.



DISCUSSION...TSTMS EXPECTED TO INCREASE IN COVERAGE AND STRENGTH

THROUGH EARLY MONDAY IN ZONE OF INCREASING WAA/DPVA DOWNSTREAM FROM

AMPLIFYING NRN STREAM SHORTWAVE TROUGH.  STEEP MID LVL LAPSE

RATES...COOL MEAN TEMP PROFILES...INCREASING PWS WITH EWD

EXTENT...AND MODERATE WNWLY CLOUD LAYER FLOW SUGGEST GOOD RISK FOR

SVR HAIL AND POSSIBLY LCLY DMGG WIND WITH THE SLIGHTLY ELEVATED

STORMS.



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 450. MEAN STORM

MOTION VECTOR 29030.





...CORFIDI

