

590 

WWUS20 KWNS 262147

SEL2

SPC WW 262147

MTZ000-WYZ000-270400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 222

NWS STORM PREDICTION CENTER NORMAN OK

350 PM MDT SUN MAY 26 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  PARTS OF CENTRAL AND SOUTHEAST MONTANA

  NORTHEAST WYOMING



* EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 350 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

  A FEW DAMAGING WIND GUSTS TO 70 MPH POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 80

STATUTE MILES EAST AND WEST OF A LINE FROM 60 MILES NORTHEAST OF

LEWISTOWN MONTANA TO 60 MILES SOUTH SOUTHWEST OF BROADUS MONTANA.

 FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU2).



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...ONGOING STORMS FROM CENTRAL MT INTO NE WY ARE EXPECTED

TO INTENSIFY SOME THE NEXT FEW HOURS AS SURFACE HEATING CONTINUES IN

THE DOWNSTREAM AIR MASS...AND ADDITIONAL STORMS WILL LIKELY DEVELOP

AS THIS AREA IS BRUSHED BY AN EJECTING SPEED MAX OVER THE NRN

ROCKIES.  THE COMBINATION OF MODERATE INSTABILITY AND SUFFICIENT

VERTICAL SHEAR WILL SUPPORT THE RISK FOR A FEW SUPERCELLS WITH LARGE

HAIL THE NEXT FEW HOURS.  LATER THIS EVENING...STORM MERGERS COULD

LEAD TO THE GROWTH OF A CLUSTER OR LINE SEGMENTS...WITH THE RISK FOR

DAMAGING WINDS.



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 26025.





...THOMPSON

