927
FXUS65 KGGW 221215
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
515 AM MST Fri Nov 22 2024

.DISCUSSION...

KEY MESSAGES:

 - Winter Weather Advisory has been issued for areas north of the
   Missouri River for this afternoon through Sunday afternoon.

 - This afternoon and evening, snow is expected across the north
   with a wintry mix to the south.

 - Another round of snow is expected on Saturday and Saturday
   night. Total snow accumulations of 2 to 4 inches north and
   trace to 2 inches south are anticipated.

 - A well-below normal period of temperatures are in store
   beginning Sunday evening.

WEATHER PATTERN OVERVIEW:

Ridging over the Northern Rockies with deep upper low off the
Pacific Northwest is spreading Pacific moisture northward across
the divide into eastern Montana today. At the surface, Canadian
high pressure is pushing cold air southward. As the Pacific
moisture overrides the cold air, precipiation will spread east
today. To the south where the cold is shallower and lift not as
favorable, there is a chance of a wintry mix including freezing
rain. Precipitation chances improve to the north with the deeper
cold air and is expected to occur mostly as snow.

A brief lull in the precipitation is expected early Saturday
morning, before a shortwave ejecting from the Pacific low rides
through the northern Rockies and spins up a lee low over southwest
Montana. A quick surge of warmer air in advance of this wave could
produce some mixed precipitation over the northern zones, mainly
as sleet, before transitioning to snow for most of Saturday into
Saturday night.

Into next week, the Pacific northwest low gradually weakens and
moves east, with a broad trough forming across the CONUS and a
ridge off the west coast. This will open the Arctic to spread cold
air southward into the northern Plains.

FORECAST CONFIDENCE & DEVIATIONS:

There is a low confidence in impacts as a result of ice
accumulations from the freezing rain threat this evening. As of
now, the area with the greatest freezing rain threat appears to be
between US Highway 2 and MT-Highway 200. Sleet is also possible
along US Highway 2 on Saturday morning.



&&

.AVIATION...
VFR to MVFR with occasional IFR conditions late. Incoming storm
will lower ceilings across the area. MVFR ceilings at KGGW will
expand to other terminals through the morning. Snow will move
into the area around 21Z and bring visibilities that could drop to
IFR until the late evening.

FREEZING RAIN: There is a roughly 10 to 20% chance that light
freezing rain could impact KGDV from 00z to 06z this evening
along with the chance for snow. Accumulations are not expected.

&&

.GGW WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 9 AM this morning to 5 PM MST
Sunday for Central and Southeast Phillips-Central and Southern
Valley-Daniels-Eastern Roosevelt-Northern Phillips-Northern
Valley-Sheridan-Southwest Phillips-Western Roosevelt.

&&

$$

weather.gov/glasgow