

882 

WWUS20 KWNS 252354

SEL5

SPC WW 252354

MTZ000-NDZ000-260700-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 685

NWS STORM PREDICTION CENTER NORMAN OK

550 PM MDT MON JUL 25 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL AND EASTERN MONTANA

       WESTERN NORTH DAKOTA



EFFECTIVE THIS MONDAY AFTERNOON AND TUESDAY MORNING FROM 550 PM

UNTIL 100 AM MDT.



HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 75

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 80

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 60 MILES SOUTHWEST

OF HAVRE MONTANA TO 30 MILES NORTHEAST OF DICKINSON NORTH DAKOTA.

 FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU5).



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 684...



DISCUSSION...TSTMS NOW FORMING IN CNTRL MT EXPECTED TO INCREASE IN

STRENGTH AND POSSIBLY COVERAGE AS THEY CONTINUE MOVING/DEVELOPING

ENE INTO REGION OF INCREASING LOW LVL MOISTURE AND SELY LOW LVL

FLOW.  INVERTED VEE ENVIRONMENT AND MODERATE SWLY MID LVL FLOW

SUGGEST POTENTIAL FOR STRONG/SVR WINDS.  ACTIVITY MAY INCLUDE A FEW

SUPERCELLS WITH HIGH WIND AND HAIL IN ERN MT...AND THE STORMS THERE

MAY EVOLVE INTO ONE OR TWO LOOSELY ORGANIZED MCSS LATER THIS EVE.

ASSOCIATED BOWING SEGMENTS MAY MAINTAIN A RISK FOR SVR

WIND/HAIL...AND POSSIBLY AN BRIEF TORNADO...THROUGH LATE TNGT.

IN THE MEAN TIME...SUSTAINED SVR STORMS/SUPERCELLS NOW IN SE MT AND

NW SD MAY SPREAD NEWD INTO FAR SW ND THIS EVE...GIVEN LOW LVL SELY

FLOW BENEATH NOCTURNALLY-STRENGTHENING SLY LLJ...AND SLOWLY

INCREASING SSWLY MID LVL FLOW DOWNSTREAM FROM PACIFIC NW UPR TROUGH.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 65

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 24035.





...CORFIDI

