FXUS65 KGGW 120514

AFDGGW



Area Forecast Discussion

National Weather Service Glasgow MT

1014 PM MST Thu Dec 11 2025



.DISCUSSION...



KEY MESSAGES:

- A quick arctic cold front will continue to push southward 

  through the region and remain here over the next few days.



- Another strong winter storm with significant snow accumulation

  is expected overnight tonight through Saturday morning.

 

 

WEATHER PATTERN OVERVIEW:

The wet mix of rain and heavy snow from earlier this morning has 

given way to more scattered snow showers this afternoon and a 

sudden push of arctic cold temperatures and gusty winds from 

Saskatchewan.



Another round of headline hazard products have been issued to

cover multiple winter conditions. 



The cold air mass has already plunged southward across the

international border. Afternoon temperatures continue to drop

quickly, pushed along by gusty winds up to 40 to 50 mph from the 

north. To cover the concerns for the resultant hazardous wind

chills, a Cold Weather Advisory and an Extreme Cold Warning have

been issued. Temperature model data for this cold time period are

highly variable, so, sudden fluctuations in wind chills and

temperatures are possible. Next few shifts will need to watch

closely for the possible need to adjust these headlines. 



The next organized snow storm comes our way from the Canadian

Rockies along an embedded strong low pressure system combining

with plentiful moisture riding up and over the US Rockies. Models

are in fairly good agreement showing roughly a 30-hour period of

snowfall for the region. Locally a wide range of snowfall totals

can be expected, with just a trace of snow for locations like 

Westby and Plentywood, and around 12 inches of snow for locations

like Zortman and Winnett. A fairly tight gradient of snowfall

totals can be expected for locations in between, showing a 

possible 3 to 8 inches. To cover these snowfall concerns, a Winter

Weather Advisory and a Winter Storm warning have been issued.



Most of these winter conditions will quickly subside on Sunday as

the strong low pressure moves away toward the east and warmer 

high pressure pushes into our region from the west. Temperatures 

are expected to rebound to much warmer, being aided by a chinook 

event off the east side of the northern Rockies.



But, areas with more snowfall will obviously take longer to 

accept the suddenly warmer temperatures on Sunday and Monday, and 

the warm up for these locations will likely be more gradual than 

is shown the model data.





FORECAST CONFIDENCE & DEVIATIONS:

Sudden drop temperatures to below zero levels - confidence high. 

Exact details of how cold it actually gets - confidence low.



General idea of the next snow storm with widespread accumulation -

confidence high.

Exact snowfall amounts - confidence average to below average. 



Given the recent large divergence between NBM and actual

conditions experienced here this morning, I have deviated from the

given NBM for the first 2 1/2 days in the forecast, increasing

precip amounts, chances for precip, and snow amounts. Also

dropping cold temperatures more than NBM.





&&



.AVIATION...



LAST UPDATED: 0500Z



FLIGHT CAT RANGE: VFR - IFR 



DISCUSSION: A very strong winter storm system with multiple 

impacts will persist through this weekend. MVFR to VFR ceilings 

will continue through Friday and Saturday. IFR Visibility from a 

new round of snow is expected to creep into the terminals again around

22 to 03Z this afternoon/evening and will hold steady until about

mid-morning Saturday. 



WIND: NW at 15 to 20 kts through mid-morning. Reducing to 10 to 15

kts or less late morning. Becoming light and slowly veering east

in the afternoon and then increasing to 5 to 15 kts in the

evening. 



/GAH





&&



.GGW WATCHES/WARNINGS/ADVISORIES...

Winter Storm Warning until 8 AM MST Saturday for Central and 

Southeast Phillips-Central and Southern Valley-Dawson-Garfield-

McCone-Northern Phillips-Petroleum-Prairie-Southwest Phillips-

Wibaux.



Cold Weather Advisory until noon MST Saturday for Central and 

Southern Valley-Dawson-Eastern Roosevelt-McCone-Northern 

Phillips-Richland-Western Roosevelt-Wibaux.



Extreme Cold Warning until noon MST Friday for Daniels-Northern 

Valley-Sheridan.



Winter Weather Advisory from 2 PM Friday to 8 AM MST Saturday 

for Daniels-Eastern Roosevelt-Northern Valley-Richland-Western 

Roosevelt.





&&



$$



weather.gov/glasgow