WATCHES: Severe Thunderstorm Watch Number 283

WWUS20 KWNS 211955
SEL3
SPC WW 211955
SDZ000-WYZ000-220400-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 283
NWS STORM PREDICTION CENTER NORMAN OK
255 PM CDT MON MAY 21 2007

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

WESTERN AND CENTRAL SOUTH DAKOTA
NORTHEAST WYOMING

EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 255 PM UNTIL
1100 PM CDT.

HAIL TO 2 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 90
STATUTE MILES EAST AND WEST OF A LINE FROM 70 MILES WEST
NORTHWEST OF MOBRIDGE SOUTH DAKOTA TO 70 MILES SOUTH OF RAPID
CITY SOUTH DAKOTA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).

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 282...

DISCUSSION...TSTMS/POSSIBLE SUPERCELLS EXPECTED TO FORM IN THE NEXT
HOUR OR SO BOTH INVOF THE BLACK HILLS AND ALONG NNE/SSW PREFRONTAL
TROUGH IN WRN PART OF WW. ENVIRONMENT IN NRN HALF OF WW IS MORE
LIKE THAT IN ND...AND SHOULD SUPPORT A FEW SUSTAINED STORMS WITH
HAIL/WIND AND POSSIBLY A BRIEF TORNADO BEFORE ACTIVITY CONGEALS INTO
A BROKEN LINE. FARTHER S...SETUP APPEARS MORE CONDUCIVE TO CLUSTERS
OF HIGH-BASED ACTIVITY WITH A THREAT FOR HIGH WIND FROM FORWARD
PROPAGATING BOWING SEGMENTS.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 22025.

..CORFIDI

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