724
FXUS65 KGGW 171103
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
403 AM MST WED DEC 17 2025
KEY MESSAGES
- A HIGH WIND WARNING REMAINS IN EFFECT FOR ALL OF NORTHEAST MONTANA
THROUGH LATE TONIGHT.
- A BLIZZARD WARNING HAS BEEN ISSUED FOR A PORTION OF THE AREA
LATE THIS AFTERNOON AND TONIGHT FOR AREAS OF WHITEOUT CONDITIONS
FROM FALLING/BLOWING SNOW.
- A COLD WEATHER ADVISORY IS IN EFFECT FOR SHARPLY COLDER
CONDITIONS IN FAR NE MONTANA TONIGHT BRINGING WIND CHILLS AS LOW
AS -30.
DISCUSSION
WEATHER PATTERN OVERVIEW:
MODEL AGREEMENT CONTINUES TO LINE UP WELL FOR A WIDESPREAD, LONG-
DURATION HIGH WIND EVENT ACROSS THE REGION ASSOCIATED WITH A
POTENT LOW PRESSURE SYSTEM COMING OFF THE CANADIAN ROCKIES. AFTER
AN INITIAL PUSH LATE THIS AFTERNOON AND EVENING MARKS THE START OF
THESE HIGH WINDS FROM THE WEST, A SHARP COLD FRONTAL PASSAGE FROM
THE NORTHWEST THIS EVENING BRINGS CONCERNS FOR WHITEOUT
CONDITIONS FROM FALLING/BLOWING SNOW AND BITTERLY COLD WIND
CHILLS. AREAS OF SUSTAINED WINDS OVER 40 MPH AND GUSTS OVER 60 MPH
WILL BE COMMON LATE THIS AFTERNOON AND EVENING, WITH SOME GUSTS
OVER 70 MPH EXPECTED FROM THIS HIGH END EVENT.
WHILE SNOWFALL AMOUNTS ARE NOT EXPECTED TO BE MUCH MORE THAN AN
INCH OR TWO, THE PERSISTENT STRONG WINDS CAN EASILY LEAD TO
PERIODS OF NEAR-WHITE OUT CONDITIONS ONCE SNOW SQUALLS PUT DOWN
FRESH SNOW AND FOR A WHILE AFTER IT STOPS FALLING. WITH MORE
POTENTIAL SHOWN IN SHORT TERM MODELS FOR THE HIGH WINDS BRINGING
1/4 MILE OR LESS VISIBILITY FOR AT LEAST 3 HOURS ACROSS A
SIGNIFICANT AREA, WENT AHEAD WITH A BLIZZARD WARNING PRIMARILY
FOR BLOWING SNOW IN UNSHELTERED AREAS. THE HIGHEST FORECAST SNOW
AMOUNTS OF 2-3" NEAR THE CANADIAN BORDER AND BIG SHEEPS WILL
ENHANCE BLOWING SNOW POTENTIAL WITH SOME OF THE WORST CONDITIONS
EXPECTED IN EXPOSED, ELEVATED AREAS THERE. TO THE SOUTH WHERE
THERE IS UNDER AN INCH OF SNOW FORECASTED, A WINTER WEATHER
ADVISORY IS IN EFFECT FOR MORE LIMITED BLOWING SNOW. WIND CHILLS
AS LOW AS 25 TO 30 BELOW ARE EXPECTED LATE TONIGHT INTO THURSDAY
MORNING WITH A COLD WEATHER ADVISORY ISSUED ALONG AND NORTH OF A
LINE FROM NORTHERN PHILLIPS TO RICHLAND COUNTIES. TRAVEL DURING
ALL THIS TIME WILL BE PARTICULARLY DANGEROUS WITH THE COMBINED
WIND, COLD AND SNOW/VISIBILITY HAZARDS, ESPECIALLY FOR HIGH-
PROFILE VEHICLES.
THE STRONG WINDS WILL QUICKLY DIMINISH THURSDAY MORNING WITH A
WARMING TREND THROUGH FRIDAY. THE NEXT CHANCE FOR LIGHT MIXED
PRECIPITATION COMES WITH THIS TRANSITION THURSDAY NIGHT INTO
FRIDAY.
FORECAST CONFIDENCE & DEVIATIONS:
BLENDED WITH HIGHER RESOLUTION AND HIGHER END GUIDANCE THROUGH
THURSDAY, FOCUSING ON THE STRONG WINDS AND TIMING OF SNOWFALL. CONFIDENCE
IS HIGH FOR THE STRONG WINDS WEDNESDAY AFTERNOON AND NIGHT.
CONFIDENCE IS MODERATE ON HOW LONG AND WIDESPREAD BLIZZARD
CONDITIONS WILL BE PRESENT TONIGHT, WITH HIGHEST CONFIDENCE NEAR
THE CANADIAN BORDER AND BIG SHEEPS.
-JEZ
AVIATION
UPDATED: 1030Z
FLIGHT CATEGORY: VFR-MVFR, THEN AREAS LIFR-VLIFR AFTER 00Z
DISCUSSION: DURING THE DAY STRONG WINDS WILL BE THE PRIMARY IMPACT
WITH 30-40 KTS SUSTAINED AND GUSTS UP TO 60 KTS OUT OF THE WEST
AFTER 20Z FOR THE TAF SITES, PEAKING IN THE EVENING. THEN,
ATTENTION TURNS TO FALLING AND BLOWING SNOW SIGNIFICANTLY REDUCING
VISIBILITY BETWEEN ABOUT 00Z AND 12Z TONIGHT. WHILE THE MOST
PERSISTENT 1/4 MILE OR LESS VISIBILITY LIKELY STAYS AWAY FROM THE
TERMINALS, THIS WILL BE A PERIOD WHERE THE HIGH WINDS WILL CAUSE
EVEN ABOUT AN INCH OF FRESH SNOW TO CAUSE BLOWING AND DRIFTING
ACROSS RUNWAYS.
LLWS: THERE WILL BE PERIODS OF LLWS THROUGHOUT THE TAF CYCLE,
PARTICULARLY BEFORE 18Z THIS MORNING.
GGW WATCHES/WARNINGS/ADVISORIES
HIGH WIND WARNING FROM 8 AM THIS MORNING TO 3 AM MST THURSDAY
FOR CENTRAL AND SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN VALLEY-
DANIELS-DAWSON-EASTERN ROOSEVELT-GARFIELD-MCCONE-NORTHERN
PHILLIPS-NORTHERN VALLEY-PETROLEUM-PRAIRIE-RICHLAND-SHERIDAN-
SOUTHWEST PHILLIPS-WESTERN ROOSEVELT-WIBAUX.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM MST
THURSDAY FOR CENTRAL AND SOUTHEAST PHILLIPS-GARFIELD-PRAIRIE-
SOUTHWEST PHILLIPS-WIBAUX.
BLIZZARD WARNING FROM 4 PM THIS AFTERNOON TO 6 AM MST THURSDAY
FOR CENTRAL AND SOUTHERN VALLEY-DANIELS-DAWSON-EASTERN ROOSEVELT-
MCCONE-NORTHERN PHILLIPS-NORTHERN VALLEY-RICHLAND-SHERIDAN-
WESTERN ROOSEVELT.
COLD WEATHER ADVISORY FROM 10 PM THIS EVENING TO 10 AM MST
THURSDAY FOR CENTRAL AND SOUTHERN VALLEY-DANIELS-EASTERN
ROOSEVELT-NORTHERN PHILLIPS-NORTHERN VALLEY-RICHLAND-SHERIDAN-
WESTERN ROOSEVELT.
WEATHER.GOV/GLASGOW
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