WATCHES: Severe Thunderstorm Watch Number 614

WWUS20 KWNS 232030
SEL4
SPC WW 232030
COZ000-KSZ000-NEZ000-240400-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 614
NWS STORM PREDICTION CENTER NORMAN OK
330 PM CDT THU JUL 23 2009

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

PARTS OF NORTHEAST COLORADO
PARTS OF NORTHWEST KANSAS
WESTERN NEBRASKA

EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 330 PM UNTIL
1100 PM CDT.

HAIL TO 2.5 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 40 MILES WEST
NORTHWEST OF VALENTINE NEBRASKA TO 40 MILES SOUTH SOUTHEAST OF
BURLINGTON 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.

DISCUSSION...AIR MASS WITH STRONG HEATING HAS BECOME MDTLY UNSTABLE
WITH MLCAPES AOA 2000 J/KG ACROSS THE WATCH. EFFECTIVE SHEAR OF
30KT IN NWLY FLOW REGIME WILL SUPPORT ROTATING STORMS.
THUNDERSTORMS ARE DEVELOPING ALONG WESTERN AREA OF GREATEST
INSTABILITY AND WILL MOVE/PROPAGATE SEWD ACROSS THE WATCH. VERY
LARGE HAIL IS PRIMARY THREAT WITH PARTICULARLY ANY SUPERCELL THAT
DEVELOPS. DAMAGING DOWNBURSTS WINDS ARE ALSO POSSIBLE AS WELL AS
ISOLATED BRIEF TORNADOS.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM
MOTION VECTOR 33025.

...HALES

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