WATCHES: Severe Thunderstorm Watch Number 299

WWUS20 KWNS 122028
SEL9
SPC WW 122028
MTZ000-130400-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 299
NWS STORM PREDICTION CENTER NORMAN OK
230 PM MDT WED JUN 12 2013

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
CENTRAL MONTANA

* EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 230 PM
UNTIL 1000 PM MDT.

* PRIMARY THREATS INCLUDE...
SEVERAL LARGE HAIL EVENTS WITH A FEW VERY LARGE HAIL EVENTS TO 2
INCHES IN DIAMETER POSSIBLE
SEVERAL DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 65
STATUTE MILES EAST AND WEST OF A LINE FROM 30 MILES NORTH
NORTHWEST OF HAVRE MONTANA TO 40 MILES EAST OF DILLON MONTANA.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU9).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 298...

DISCUSSION...STORMS ARE EXPECTED TO INCREASE AMIDST MODESTLY
UNSTABLE AIRMASS AND STRENGTHENING DEEP-LAYER FLOW THROUGH THE
EVENING HOURS. MOIST UPSLOPE FLOW REGIME IN THE LOWER LEVELS TOPPED
BY STRONGER SWLY FLOW ALOFT SHOULD CONTRIBUTE TO SUPERCELL STORM
STRUCTURES WITH PERSISTENT UPDRAFTS POSING A THREAT OF LARGE HAIL
AND DAMAGING DOWNBURST WINDS. AN ISOLATED TORNADO CANNOT BE RULED
OUT GIVEN RELATIVELY MOIST BOUNDARY LAYER AND ADEQUATE LOW LEVEL
STORM RELATIVE HELICITY SUPPORTED BY ELY COMPONENT OF THE LOW LEVEL
FLOW.

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 400. MEAN STORM
MOTION VECTOR 24030.


...CARBIN

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