429
FXUS65 KGGW 300634
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
1234 AM MDT SUN AUG 30 2026
KEY MESSAGES
- A COLD FRONT WILL BRING LOWER TEMPERATURES BUT CONTINUED CHANCES
FOR THUNDERSTORMS ON SUNDAY. SOME STORMS MAY PRODUCE SEVERE WIND
GUSTS AND BRIEF HEAVY RAINFALL.
- A LAKE WIND ADVISORY CONTINUES FOR FORT PECK LAKE THROUGH 6 PM
MDT SUNDAY.
- TEMPERATURES WILL RECOVER FOR THE SECOND HALF OF THE WEEK WITH
HIGHS EACH DAY LARGELY IN THE 80S.
DISCUSSION
WEATHER PATTERN OVERVIEW:
A COLD FRONT AND UPPER TROUGH WILL DELIVER A COMBINATION OF LOWER
TEMPERATURES, INCREASING WEST TO NORTHWEST WINDS, AND CONTINUED
SHOWERS AND THUNDERSTORMS FOR SUNDAY. SPC MAINTAINS A MARGINAL
RISK FOR THE EAST WHERE SEVERE WIND GUSTS ARE A CONCERN. THESE
LOCATIONS WILL SEE THE WARMEST DAYTIME TEMPERATURES AND MORE
UNSTABLE CONDITIONS. OVERALL, HREF SHOWS TIMING AS EARLY AS 18Z
FOR THE WIND THREAT EMERGING, WITH ACTIVITY EVOLVING EAST BY
EVENING HOURS. A FEW OF THE STORMS MAY PRODUCE LOCALLY HEAVY
RAINFALL AS WELL.
AS WEST WINDS RAMP UP ON SUNDAY, A LAKE WIND ADVISORY FOR FORT
PECK LAKE REMAINS IN EFFECT UNTIL 6 PM MDT. WINDY CONDITIONS WILL
RELAX DURING THE EVENING BUT RAMP BACK UP ON MONDAY. THAT SAID,
WILL DEFER HEADLINE DECISIONS UNTIL LATER AS TRENDS HAVE SHIFTED
WINDS TO BE MORE FOCUSED ON THE EAST SIDE OF THE LAKE.
UPPER RIDGING WILL THEN GUIDE WARMER AND DRIER CONDITIONS TO NE
MONTANA FOR TUESDAY. THE RIDGE AXIS LOOKS TO SLIDE EAST LATE IN
THE WEEK WITH DIFFLUENT SOUTHWEST UPPER FLOW BECOMING ESTABLISHED
OVER THE NORTHERN HIGH PLAINS. IN SHORT, THE NEXT ROUND OF
THUNDERSTORMS MAY GET UNDERWAY AS EARLY AS WEDNESDAY EVENING.
FORECAST CONFIDENCE & DEVIATIONS:
NBM WAS GIVEN A MODEST BLEND WITH NBM90 FOR AN UPWARD NUDGE GIVEN
THE COLD AIR ADVECTION. POPS WERE ADJUSTED FOR NEAR TERM
COLLABORATION AND CONSISTENCY. OTHERWISE THERE WERE NO MAJOR
DEVIATIONS WITH MODEL CONSENSUS LENDING TO ABOVE AVERAGE
CONFIDENCE THIS FORECAST CYCLE FOR COOLER TEMPERATURES WITH
THUNDERSTORM CHANCES ON SUNDAY, FOLLOWED BY QUIET WEATHER ON
TUESDAY. CONFIDENCE IS ALSO INCREASING ON MORE ACTIVE WEATHER IN
THE FORM OF THUNDERSTORMS BY MIDWEEK AS THE RIDGE TRANSLATES
DOWNSTREAM, SUPPORTED BY DYNAMIC LIFT AND INCREASED INSTABILITY.
AVIATION
LAST UPDATED: SUNDAY AUGUST 30 AT 0630Z.
FLIGHT CAT RANGE: VFR, MVFR IN THUNDERSTORMS.
DISCUSSION: AN UPPER TROUGH WILL HELP MAINTAIN SHOWER AND
THUNDERSTORM CHANCES ACROSS AREA TERMINALS FOR SUNDAY.
WINDS: VARIABLE WINDS WILL BECOME WEST TO NORTHWEST AT 10 TO 20
KTS, GUSTING TO 30 KTS. WINDS LOOK TO DIMINISH AFTER 01Z SUNDAY.
GGW WATCHES/WARNINGS/ADVISORIES
LAKE WIND ADVISORY FROM 7 AM THIS MORNING TO 6 PM MDT THIS
EVENING FOR CENTRAL AND SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN
VALLEY-GARFIELD-MCCONE-PETROLEUM.
WEATHER.GOV/GLASGOW
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