554
FXUS65 KGGW 122011
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
211 PM MDT SAT SEP 12 2026
KEY MESSAGES
- RAIN WILL BE LIKELY ACROSS NORTHEAST PORTIONS OF MONTANA SUNDAY
AFTERNOON THROUGH MONDAY MORNING. PRECIPITATION TOTALS WILL
RANGE BETWEEN 0.01" AND 0.25".
- A LAKE WIND ADVISORY HAS BEEN ISSUED DUE TO WIND SPEEDS BEING
EXPECTED TO REACH 20 TO 25 MPH SUSTAINED SUNDAY AFTERNOON. WAVE
HEIGHTS HAVE THE POTENTIAL TO REACH 3 FT.
- WINDS WILL LIKELY REACH LAKE WIND ADVISORY CRITERIA AGAIN
MONDAY AFTERNOON. WAVE HEIGHTS HAVE THE POTENTIAL TO REACH 4.5
FT.
DISCUSSION
ZONAL WESTERLY FLOW ALOFT SOUTH OF AN UPPER-LEVEL TROUGH IN
CENTRAL CANADA WILL CONTINUE TRANSPORTING MOISTURE INTO THE
REGION, PRODUCING CLOUDY SKIES TODAY.
AN EASTERN-PACIFIC TROUGH WILL MOVE ONSHORE OVER OREGON BY
TOMORROW MORNING BEFORE DIGGING OVER WESTERN MONTANA BY MID-
AFTERNOON. INSTABILITY AND LOW-LEVEL MOISTURE ASSOCIATED WITH THE
TROUGH WILL LIKELY PRODUCE RAIN ACROSS NORTHEAST PORTIONS OF
MONTANA SUNDAY AFTERNOON THROUGH MONDAY MORNING. PRECIPITATION
TOTALS WILL RANGE BETWEEN 0.01" AND 0.25".
SE SURFACE WINDS WILL REACH SPEEDS OF 20 TO 25 MPH SUSTAINED SUNDAY
AFTERNOON, WITH GUSTS POTENTIALLY REACHING 35 MPH, THEREFORE A
LAKE WIND ADVISORY HAS BEEN ISSUED. WINDS WILL VEER WESTERLY
MONDAY AS ZONAL FLOW ALOFT BECOMES PREDOMINANT AND THE TROUGH
BEGINS EXITING EASTWARD. WINDS OF COMPARABLE STRENGTH REACHING
ADVISORY CRITERIA ARE EXPECTED. WAVE HEIGHTS HAVE THE POTENTIAL TO
REACH 4.5 FT, PARTICULARLY MONDAY AFTERNOON.
THE TROUGH WILL FULLY EXIT THE REGION OVERNIGHT MONDAY WHILE THE
ZONAL FLOW LEFT IN ITS WAKE BEGINS BUILDING INTO A WEAK RIDGING
PATTERN. SLIGHT CHANCES FOR RAIN SHOWERS ARE POSSIBLE TUESDAY
NIGHT INTO WEDNESDAY MORNING DUE TO A SWATH OF LOW-LEVEL MOISTURE
MOVING THROUGHOUT. CONFIDENCE IN RAIN AMOUNTS ARE LOW. RAIN
CHANCES DIMISH WEDNESDAY AFTERNOON AS SKIES CLEAR AND TEMPERATURES
WARM UNDER THE RIDGE THROUGH THE REMAINDER OF THE WEEK.
FORECAST CONFIDENCE & DEVIATIONS:
THERE IS MODERATE TO HIGH CONFIDENCE IN SUSTAINED WINDS AT OR
ABOVE 20 MPH ON SUNDAY AND MONDAY ACROSS FORT PECK LAKE.
THERE IS LOW CONFIDENCE IN RAIN AMOUNTS TUESDAY NIGHT INTO
WEDNESDAY.
DON
AVIATION
LAST UPDATED: 2000Z
FLIGHT CAT RANGE: VFR
DISCUSSION:
EXPECT CLOUDS TO SCATTER OUT AND RISE THIS EVENING AND OVERNIGHT.
A MID-LEVEL SCT CLOUD DECK WILL LIKELY REDEVELOP TOMORROW MORNING
BETWEEN 10,000' AND 12,000' AGL BEFORE LOWERING AND THICKEING
INTO THE EVENING AS PRECIPITATION BECOMES IMMINENT.
W-NW WIND AT 5 TO 10 KT THIS AFTERNOON WILL VEER N THIS EVENING.
WIND WILL THEN BECOME SE AND INCREASE TO 15 TO 20 KT BY TOMORROW
MORNING.
DON
GGW WATCHES/WARNINGS/ADVISORIES
LAKE WIND ADVISORY FROM 10 AM SUNDAY TO MIDNIGHT MDT SUNDAY
NIGHT FOR CENTRAL AND SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN
VALLEY-GARFIELD-MCCONE-PETROLEUM.
WEATHER.GOV/GLASGOW
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