395
FXUS65 KGGW 122011
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
211 PM MDT WED AUG 12 2026
KEY MESSAGES
- ISOLATED SHOWERS WILL DRIFT ACROSS NORTHEAST MONTANA TODAY AS
WINDS BEGIN TO PICK UP AHEAD OF A MAJOR PATTERN SHIFT.
- THURSDAY AND FRIDAY WILL SEE COOLER AND WETTER CONDITIONS. OVER
A 48 HOUR PERIOD, MANY LOCATIONS COULD SEE OVER OF AN INCH OF
ACCUMULATED RAINFALL.
- PRECIPITATION CHANCES DON'T COMPLETELY GO AWAY THIS WEEKEND AND
INTO EARLY NEXT WEEK, BUT OVERALL CONDITIONS WILL TREND TOWARDS
DRIER AND WARMER.
DISCUSSION
WEATHER PATTERN OVERVIEW:
TODAY AND TONIGHT, THE FLOW ALOFT WILL TRANSITION FROM AN UPPER
RIDGE TO SW FLOW ALOFT ACROSS MONTANA. MEANWHILE, AN UPPER TROUGH
MOVE INTO THE CANADIAN ROCKIES AND PACIFIC NW. THE PATTERN CHANGE
WILL LEAD TO INCREASING DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS,
WITH HEAVY RAIN POTENTIAL AS SOME SOUTHWESTERN MONSOONAL MOISTURE
DOES TRANSPORT ITS WAY THIS FAR NORTH.
THERE WILL BE CHANCES FOR SHOWERS AND THUNDERSTORMS AT TIMES
TODAY. CHANCES FOR SHOWERS AND THUNDERSTORMS INCREASE TONIGHT
WITH WIDESPREAD RAIN EXPECTED BETWEEN THURSDAY, THURSDAY NIGHT AND
FRIDAY MORNING WITH HEAVY RAIN POSSIBLE AT TIMES. THE CURRENT
PROBABILITY FOR ONE INCH OR MORE RAIN BETWEEN TONIGHT AND FRIDAY
IS 40 - 90 PERCENT ACROSS NE MONTANA WITH HIGHER CONFIDENCE THE
MORE EAST YOU GO. THE PROBABILITY FOR 2 OR MORE INCHES OF RAIN
BETWEEN TONIGHT AND FRIDAY IS BETWEEN 10 AND 50 PERCENT,
ESPECIALLY EAST OF FORT PECK LAKE. IF MORE THAN 2 INCHES OF RAIN
OCCURS, FLOODING COULD BECOME A POSSIBILITY DEPENDING ON HOW
QUICKLY THE RAIN FALLS IN A GIVEN LOCATION. A MARGINAL RISK OF
EXCESSIVE RAINFALL FOR NE MONTANA TODAY, AND A SLIGHT RISK
THURSDAY, AND ANOTHER MARGINAL FOR FRIDAY. WILL HOLD OFF ON ANY
FLOOD WATCHES FOR NOW GIVEN THAT THE GROUND IS DRY AND RAINFALL
HAS BEEN LIGHT OVER THE LAST 4 WEEKS.
FLOW ALOFT FRIDAY NIGHT AND SATURDAY TURNS INTO A DRIER WSW ALOFT
AS THE UPPER TROUGH MOVES EAST ACROSS THE CANADIAN PRAIRIES.
RAIN CHANCES DIMINISH FRIDAY AFTERNOON AND FRIDAY NIGHT AND
SATURDAY LOOK MAINLY DRY WITH ISOLATED SHOWERS POSSIBLE.
FREQUENT WAVES MOVING ACROSS EASTERN MONTANA WILL BRING SHOWER AND
THUNDERSTORM CHANCES AT TIMES EARLY NEXT WEEK.
FORECAST CONFIDENCE & DEVIATIONS:
INCREASED POPS FOR THE FIRST 8 HOURS TO BETTER CAPTURE AM SHOWERS.
NO CHANGES TO NBM OTHERWISE.
LOW CONFIDENCE IN SHOWER AND THUNDERSTORM CHANCES TODAY. CONFIDENCE
IN PRECIPITATION CHANCES INCREASE TONIGHT AND THURSDAY AND ARE
HIGH THURSDAY NIGHT AND FRIDAY MORNING. HIGH CONFIDENCE IN MANY
AREAS GETTING AN INCH OR MORE RAIN OVERALL BUT LOW CONFIDENCE
POSSIBILITY OF AMOUNTS HIGHER THAN AN INCH.
AVIATION
LAST UPDATE: 1900Z.
FLIGHT CAT RANGE: VFR - MVFR AFTER 18Z THURSDAY.
DISCUSSION: SKIES WILL VARY FROM BROKEN MID AND HIGH CLOUDS TODAY
WITH ISOLATED SHOWERS AND THUNDERSTORMS POSSIBLE. MID LEVEL
CLOUDS AND CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE
TONIGHT WITH LOW CLOUDS MOVING IN FROM THE WEST AFTER 09Z
THURSDAY.
WIND: NE 5 TO 15 KTS BECOMING E 5 TO 10 KTS TOMORROW MORNING.
GGW WATCHES/WARNINGS/ADVISORIES
NONE.
WEATHER.GOV/GLASGOW
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