Severe Thunderstorm Warning 25, NWS Glasgow, MT

NORTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
230 PM MDT WED JUN 27 2001

...SEVERE THUNDERSTORM WATCH UNTIL 9PM MDT FOR ZONES 22 THROUGH 27...

SUNSHINE BEGINNING TO BREAK OUT OVER SOUTH AND SOUTHEAST ZONES ATM
WITH POTENTIAL FOR SEVERE WEATHER INCREASING RAPIDLY OVER THOSE
AREAS. SPC HAS ISSUED A SVR TSTORM WATCH UNTIL 9PM MDT TO COVER IT.
ZONES NORTH OF THE MISSOURI RIVER ARE SOCKED IN WITH CLOUDS WITH
TEMPS BURIED IN THE 60S. ALL AREAS HAVE DEWPTS IN THE 60S AND WITH
ENOUGH DYNAMICS ALOFT...WE COULD SEE THUNDERSTORMS ANYWHERE THIS
EVENING...ESP WHERE CLOUDS GIVE WAY. SHEAR PROFILES ARE SUCH THAT
ROTATING SUPERCELLS ARE POSSIBLE WHERE SEVERE TSTORMS GET GOING.
MAIN THREAT WILL BE LARGE HAIL...DAMAGING WINDS AND HEAVY RAIN.

WILL SEE A DRY LINE LATE TONIGHT/THU AM WHICH SHOULD END THE SEVERE
THREAT AND SCOUR OUT CLOUDS BRINGING WARMER TEMPS. HOWEVER WITH
CONTINUED SW FLOW ALOFT AND EMBEDDED S/WAVES WILL KEEP AT LEAST LOW
SCT POPS FOR AFTERNOON TSTORMS IN FCST FOR THU.   WRIGHT

EXTENDED...MODELS STILL IN REASONABLE AGREEMENT WITH MAIN DIFFERENCE
IN LATTER PORTION OF FORECAST PERIOD WITH AMPLITUDE OF UPPER RIDGE
OVER WESTERN CANADA. MRF MORE AGRESSIVE THAN ECMWF AND IS USUALLY
OVERDONE THAT FAR OUT. REGARDLESS GENERAL PATTERN IS FOR
RETROGRADING PATTERN WITH A SERIES OF SHORTWAVES SLIDING ACROSS
WESTERN CANADA AND UPPER RIDGE REBOUNDING FURTHER WEST BEHIND EACH
SHORTWAVE. MAIN WAVE TRACKS ALONG MT/CAN BORDER SUNDAY WITH WARM AIR
ADVECTION PATTERN DEVELOPING BREIFLY AHEAD OF WAVE. FLOW BECOMES
MORE NORTHERLY BEHIND THIS WAVE WITH CANADIAN HIGH PUSHING TOWARD
DAKOTAS AND RIDGING TO THE WEST. EBERT

KGGW 062/082 057/081 057/078 058/084 051/081 054/084 057/085
      BBBTBUB  956333/9024212
KGDV 061/086 057/081 059/081 057/087 051/080 052/083 055/084
      BBBTBUB  956333/9024212