WATCHES: Severe Thunderstorm Watch Number 159

WWUS20 KWNS 132100
SEL9
SPC WW 132100
IDZ000-MTZ000-ORZ000-WAZ000-140400-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 159
NWS STORM PREDICTION CENTER NORMAN OK
300 PM MDT MON MAY 13 2013

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
CENTRAL IDAHO
WESTERN MONTANA
EXTREME NORTHEAST OREGON
EXTREME SOUTHEAST WASHINGTON

* EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 300 PM UNTIL
1000 PM MDT.

* PRIMARY THREATS INCLUDE...
SEVERAL DAMAGING WIND GUSTS TO 70 MPH POSSIBLE
SEVERAL LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 60
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 40 MILES NORTH
NORTHWEST OF BAKER OREGON TO 55 MILES EAST NORTHEAST OF GREAT
FALLS 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.

&&

DISCUSSION...THUNDERSTORMS ARE DEVELOPING OVER NERN OREGON AND
ADJACENT PARTS OF CENTRAL ID IN ADVANCE OF A STRONG SHORT WAVE
TROUGH MOVING EWD INTO WA/OREGON. SUFFICIENT MOISTURE WITH SURFACE
DEW POINTS IN THE 40S AND A DEEP MIXED LAYER AND STEEP LAPSE RATES
WILL ENHANCE POTENTIAL FOR DAMAGING WIND GUSTS AND HAIL WITH
STRONGER HIGH-BASED STORMS. THE ACTIVITY IS EXPECTED TO SPREAD
RAPIDLY ENEWD THROUGH THE EVENING HOURS OVER PARTS OF WRN MT.
ADDITIONAL STORMS MAY ALSO FORM EWD OVER THE CENTRAL MT MOUNTAINS
WITHIN THE NEXT SEVERAL HOURS...AND MODEL GUIDANCE SUGGESTS AN
ADDITIONAL WATCH FARTHER EAST IN MT MAY BE NEEDED DURING THE LATE
AFTERNOON OR EVENING.

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 400. MEAN STORM
MOTION VECTOR 24040.


...WEISS

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