WATCHES: Severe Thunderstorm Watch Number 559

WWUS20 KWNS 012040
SEL9
SPC WW 012040
MTZ000-NDZ000-020300-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 559
NWS STORM PREDICTION CENTER NORMAN OK
340 PM CDT SUN AUG 1 2010

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

NORTHEAST MONTANA
NORTHWEST NORTH DAKOTA

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 340 PM UNTIL
1000 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 60
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 35 MILES SOUTHWEST
OF WOLF POINT MONTANA TO 20 MILES NORTHEAST OF GARRISON NORTH
DAKOTA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).

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 558...

DISCUSSION...ISOLATED SUPERCELLS ARE EXPECTED TO PERSIST AND SPREAD
ESEWD FOR SEVERAL HOURS ALONG A REMNANT OUTFLOW BOUNDARY ACROSS NE
MT/NW ND. SURFACE TEMPERATURES IN THE 80S AND DEWPOINTS IN THE 60S
ALONG AND SE OF THE BOUNDARY ARE SUPPORTING MODERATE
INSTABILITY...WHILE STRAIGHT HODOGRAPHS WITH STRONG DEEP-LAYER SPEED
SHEAR WILL REMAIN FAVORABLE FOR SUPERCELLS. ISOLATED LARGE HAIL
SHOULD BE THE MAIN THREAT...THOUGH A FEW DAMAGING GUSTS MAY ALSO
OCCUR.

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 450. MEAN STORM
MOTION VECTOR 29030.

...THOMPSON

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