405
FXUS65 KGGW 161039
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
339 AM MST Sun Nov 16 2025

.DISCUSSION...

KEY MESSAGES:

- Widespread dense freezing fog continues through this morning
  across the Hi-Line and Yellowstone River Valley.

- Light precipitation chances return late tonight through
  Wednesday.

WEATHER PATTERN OVERVIEW:
With light precipitation yesterday followed by clearing skies and
light winds, areas of dense freezing fog were quick to develop in
the Malta area and spread eastward. Thus, expanded the Dense Fog
Advisor out to the ND border and Yellowstone up to Dawson county.
High resolution guidance shows the fog lingering through the mid
morning before lifting. The setup tonight is less favorable for
fog formation, but something to watch as a few model solutions
show potential in a similar area.

Today will be dry with surface high pressure over the Dakotas
before a more unsettled pattern of shortwave troughs works through
the region tonight through Wednesday. While there is a general
agreement on precipitation totals being light at around a tenth
of an inch or less, there is a slight chance for a setup favorable
for an impactful light glaze of freezing rain Tuesday morning
focused over higher elevations in northern Phillips/Valley
counties. Thus, temperature profiles and higher resolution
guidance will be helpful to assess this in the next couple of
forecast cycles.

FORECAST CONFIDENCE & DEVIATIONS:
Made typical adjustments to add resolution and higher end guidance
to winds through Monday. Confidence is low on both the occurrence
of any dense fog tonight and ice accumulation Tuesday morning.
Confidence is high for the temperature pattern this week remaining
slightly warmer than normal.

-JEZ

&&

.AVIATION...

FLIGHT CAT RANGE: Areas of LIFR before 18Z, then mostly VFR

DISCUSSION: Areas of dense freezing fog have developed overnight
impacting all TAF sites, particularly for KGGW and KSDY. There is
high confidence for this to lift between 16-18Z as a shortwave
ridge brings conditions back to the VFR category for the
afternoon Sunday. Confidence is currently low on widespread dense
fog reoccurring tonight given increased winds and cloud cover,
but lower ceilings to at least MVFR cannot be ruled out.

EQUIPMENT: KOLF`s ASOS telecom circuit is down and can not be
dialed into. Therefore, AMD NOT SKED for this TAF until repairs
can be made.

&&

.GGW WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 11 AM MST this morning for Central and
Southeast Phillips-Central and Southern Valley-Daniels-Dawson-
Eastern Roosevelt-McCone-Northern Phillips-Northern Valley-
Richland-Sheridan-Western Roosevelt-Wibaux.

&&

$$

weather.gov/glasgow