911
FXUS65 KGGW 110842
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
242 AM MDT THU SEP 11 2025
DISCUSSION
KEY MESSAGES:
- SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE OVER THE NEXT
FEW DAYS, SOME OF WHICH MAY BECOME SEVERE.
- A STORM SYSTEM FROM THE PACIFIC WILL BRING SCATTERED ROUNDS OF
RAIN SHOWERS AND THUNDERSTORMS THIS WEEKEND, MAINLY OVER FAR
EASTERN MONTANA.
WEATHER PATTERN OVERVIEW:
A SHORTWAVE TROUGH IS MOVING THROUGH AREAS SOUTHEAST OF A LINE
FROM ST. MARIE TO JORDAN TO BRING SOME THUNDERSTORMS AND HEAT
BURST ACTIVITY. THE FAR SOUTHEAST PART OF THE AREA IS SEEING
BORDERLINE SEVERE GUSTS, AND THIS ACTIVITY WILL COME TO AN END BY
AROUND 9 AM THIS MORNING. THIS WILL BE IN THE WAKE OF STRONG TO
SEVERE THUNDERSTORMS THAT COULD POP UP ANYWHERE AFTER ABOUT 2 PM
AND LAST THROUGH AROUND 2 AM. THERE IS MODERATE CONFIDENCE ON
STORMS REACHING SEVERE LIMITS, BUT LOW CONFIDENCE ON EXACTLY WHERE
AND WHEN THE STORMS WILL INITIATE. ANY THUNDERSTORMS THAT MOVE
OVER A LOCATION COULD POTENTIALLY DROP A QUICK QUARTER TO HALF AN
INCH OF RAIN TODAY THROUGH TOMORROW EVENING.
FOR SATURDAY AND SUNDAY, THE MOST RECENT UPDATE OF RAINFALL
AMOUNTS HAS SHIFTED MUCH OF THE PRECIPITATION EAST OF LINE FROM
OPHEIM DOWN TO JORDAN BASED ON THE CURRENT FORECAST OF A SHORTWAVE
MOVING THROUGH THE OVERALL LARGE WESTERN TROUGH. THIS MEANS THERE
IS MODERATE TO HIGH CONFIDENCE OF AT LEAST A WETTING RAIN
OCCURRING IN THE EAST, WITH LOW CONFIDENCE ON OTHER LOCATIONS
RECEIVING MORE THAN ONE TENTH OF AN INCH.
THERE IS LOW CONFIDENCE OF ACCUMULATING PRECIPITATION OCCURRING ON
TUESDAY AND WEDNESDAY AS A LARGE SHORTWAVE TROUGH IS EXPECTED TO
MOVE IN FROM THE WEST COAST ON MONDAY NIGHT.
FORECAST CONFIDENCE & DEVIATIONS:
DEVIATED FROM THE NBM WITH A MIX OF NBM 90 FOR WINDS FOR DAY 1 AND
2. ALSO MANUALLY ADJUSTED POPS TO COORDINATE WITH CAMS FOR THE
SAME TIME PERIOD.
THERE IS LOW TO MODERATE CONFIDENCE ON STORM SEVERITY, LOCATION,
AND TIMING OF THUNDERSTORMS TODAY AND TOMORROW. THERE IS MODERATE
TO HIGH CONFIDENCE ON THE AFOREMENTIONED RAINFALL AMOUNTS FOR THIS
WEEKEND.
AVIATION
UPDATE: 0900Z
FLIGHT CAT RANGE: VFR, MVFR IN THUNDERSTORMS.
DISCUSSION: A SHORTWAVE TROUGH IS ALLOWING STRONG THUNDERSTORMS TO
MOVE THROUGH KSDY AND KGDV THIS MORNING. THERE IS MODERATE
CONFIDENCE OF THESE STORMS BRINGING CONDITIONS DOWN TO MVFR
THROUGH 14Z. A SIGNIFICANT UPPER TROUGH OVER THE WESTERN U.S.
WILL AID IN ISOLATED AND SCATTERED STRONG TO SEVERE THUNDERSTORM
DEVELOPMENT THIS AFTERNOON AND EVENING. THERE IS MODERATE
CONFIDENCE FOR ALL TAF SITES TO SEE MVFR CONDITIONS WITH
THUNDERSTORMS.
WIND: FOR KGGW, SOUTHEAST AT 5 TO 15 KNOTS, BECOMING NORTHWEST AT
10 TO 15 KNOTS AFTER 18Z. FOR ALL OTHER SITES, SOUTHEAST AT 5 TO
12 KNOTS, BECOMING NORTH AFTER 00Z. ERRATIC WINDS NEAR
THUNDERSTORMS.
EQUIPMENT: COMMS ISSUES WITH THE KSDY OBSERVATION REMAIN. AMD NOT
SKED WILL REMAIN WITH THE TAF THERE UNTIL TRANSMISSION OF OBS
BECOMES MORE STABLE.
/GAH
GGW WATCHES/WARNINGS/ADVISORIES
NONE.
WEATHER.GOV/GLASGOW
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