275
FXUS65 KGGW 302001
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
201 PM MDT Tue Sep 30 2025

.DISCUSSION...

KEY MESSAGES:

- A slow cool down is expected through early next week.

- With an upper ridge breaking down, there may be a couple chances
  for precipitation, the first one comes tonight.

WEATHER PATTERN OVERVIEW:
An upper ridge that has kept a summer-like feel across the area
lately with dry and above normal temperatures has been shifting
east. A large upper low off the Pacific Northwest coast will
gradually move inland but weaken by late in the week.

Precipitation opportunities will start this evening with a few
general showers and maybe a weak thunderstorm or two, moving
northeast across the CWA by late tonight. Temperatures will
slowly trend downward this week as a trough from the southwest
moves in followed by a trough coming in from the northwest this
weekend.

On Thursday into Thursday night, a shortwave trough will lift
across the region, pushing a stronger cold front and the
possibility of showers through eastern Montana. There remains high
uncertainty in the details of precipitation opportunities beyond
Friday.

Temperatures look to cool to about normal Saturday, then drop
below normal Sunday and Monday.

FORECAST CONFIDENCE & DEVIATIONS:
Deviations from NBM include a change to hourly PoPs around 06-15Z
tonight as NBM was not fully catching onto the CAMs models axis of
highest rain chances as it passed through the area. Used a blend
of SREF, HRRR and RAP. This rainfall will be more beneficial as,
except for Garfield county, much of the area has experienced well
below normal rainfall this month.

NBM was followed closely for the remaining forecast elements.

There is low confidence of precipitation amounts with each
system. TFJ

&&

.AVIATION...
LAST UPDATE: 2000Z

FLIGHT CAT RANGE: VFR

DISCUSSION: Clouds will increase from the southwest with scattered
showers moving through late tonight. These are expected to be
light and not bring any flight category drops.

WIND: South winds this afternoon will turn to the NW tonight from
west to east. Speeds should generally be less than 15 kts.

EQUIPMENT: At KSDY an AMD NOT SKED will remain in place until the
METARs comms issue is repaired. TFJ

&&

.GGW WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

weather.gov/glasgow