Severe Thunderstorm Warning 9, NWS Glasgow, MT

NORTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
305 PM MDT THU JUN 19 2003

SHORT TERM...TONIGHT THROUGH SATURDAY
WIDELY SCATTERED THUNDERSTORMS DEVELOPING JUST WEST OF THE CWFA WITH
THIS TREND TO CONTINUE INTO TONIGHT. SHOWERS AND THUNDERSTORMS
EXPECTED TO DEVELOP IN ERNEST OVER CENTRAL MONTANA FRIDAY AND THEN
SPREAD EASTWARD WITH FRONTAL TROUGH FRIDAY EVENING AND NIGHT. MODEL
SOUNDINGS CONTINUE TO INDICATE A GRADUAL DECREASE IN SOUTHEASTERLY
FLOW IN THE LOWER LEVELS OF THE ATMOSPHERE THIS EVENING. HOWEVER,
THUNDERSTORM DEVELOPMENT WITH VERY LOW SURFACE PRESSURES TO THE WEST
OF THE CWFA AND GOOD MIXING UNTIL SUNSET WOULD INDICATE WINDS WILL
CONTINUE JUST BELOW OR AT LAKE WIND ADVISORY LEVELS UNTIL ABOUT
SUNSET. THUS, WILL ALLOW LAKE WIND ADVISORY TO CONTINUE THROUGH 9PM
THIS EVENING. UPPER LEVEL TROUGH TO BEGIN MOVING EASTWARD FRIDAY
WITH MAXIMUM CHANCES FOR RAINFALL STILL EXPECTED TOMORROW EVENING
AND NIGHT OVER CWFA. GRADUAL DRYING INDICATED UNDER WESTERLY FLOW
FROM WEST TO EAST ACROSS THE CWFA ON SATURDAY. LYNN

.LONG TERM...SAT NIGHT THRU THURSDAY
UNSETTLED PATTERN ENTIRE EXTENDED PERIOD AS MODELS SHOW DEEP AND
PERSISTENT MEAN UPPER TROUGH OVER WESTERN UNITED STATES. BELOW
NORMAL TEMPERATURES AND A CHANCE OF SHOWERS/THUNDER THROUGH BULK OF
PERIOD. WHILE COOL...COLD TEMPERATURES AT MID-LEVELS OF ATMOSPHERE
SUGGEST ENOUGH INSTABILITY TO INCLUDE THUNDER...PLUS IN BETTER
AGREEMENT WITH ADJACENT OFFICES. ETA/AVN SHOW DRYING AND PARTIAL
CLEARING SATURDAY NIGHT...BUT HAVE INTRODUCED SLIGHT CHANCE OF
SHOWERS AND PARTLY CLOUDY TO COOPERATE WITH ADJACENT OFFICES WANTING
CHANCE POPS. EXPECT SECOND DRY AIRMASS TO PUSH IN SUNDAY NIGHT...
WHICH IS ALREADY IN GRIDS. DRY PERIOD COULD LINGER INTO MONDAY
MORNING BUT AGAIN HAVE ADJUSTED TO INCLUDE CHANCE OF PRECIPITATION
TO COORDINATE WITH ADJACENT OFFICES. GFS SHOWS SECOND...REINFORCING
TROUGH ROTATING SOUTHEAST OUT OF GULF OF ALASKA EARLY NEXT WEEK
WHICH THEN PERSISTS THROUGH END OF PERIOD. WHILE REASONABLY
CONFIDENT WITH SYNOPTIC SCALE TREND IN FORECAST...MUST BROADBRUSH
GRIDS BECAUSE OF UNCERTAINTY OVER TIMING OF INDIVIDUAL VORTICITY
CENTERS ON MESO SCALE ROTATING AROUND LONG WAVE TROUGH. INHERITED
VERY COOL GRIDS...MADE MINOR ADJUSTMENTS TO BLEND BETTER WITH
GENERALLY SLIGHTLY WARMER GRIDS AT ADJACENT OFFICES. DNS

KGGW TTE 060/086 056/073 051/069 77366322
     TTTT 048/070 049/069 049/070 049/073 8603333333
KGDV TTE 061/090 057/077 054/071 77046322
     TTTT 045/072 050/071 050/072 050/075 8603333333

.GGW...LAKE WIND ADVISORY THROUGH 03Z THIS EVENING FOR FORT PECK
LAKE.

MTZ016>027-059>062-201200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GLASGOW MT
257 PM MDT THU JUN 19 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST MONTANA

.DAY ONE...
A LAKE WIND ADVISORY IS IN EFFECT FOR FORT PECK LAKE FOR TODAY
THROUGH 9 PM THIS EVENING. SEE GTFNPWGGW OR WWUS75 KGGW FOR FURTHER
INFORMATION. THERE IS A CHANCE FOR THUNDERSTORMS TONIGHT WEST OF
SCOBEY...WOLF POINT AND CIRCLE. A FEW OF THESE STORMS MAY BECOME
SEVERE WITH LARGE HAIL AND WIND GUSTS IN EXCESS OF 60 MPH.

.DAYS TWO THROUGH SEVEN...
A STRONG COLD FRONT WILL MOVE EAST ACROSS NORTHEAST MONTANA FRIDAY
AFTERNOON AND FRIDAY NIGHT. THUNDERSTORMS ARE LIKELY ALONG AND AHEAD
OF THIS FRONT. SOME OF THESE STORMS WILL BECOME SEVERE WITH WIND
GUSTS IN EXCESS OF 60 MPH AND LARGE HAIL.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.