543
FXUS65 KGGW 291900
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
100 PM MDT Tue Sep 29 2026

.KEY MESSAGES...
- Warm, dry, and gusty conditions this afternoon is expected to
  quieter conditions with decreasing winds later today.

- The first major frost of the season is possible is some
  locations Thursday morning.

- There are small chances for isolated showers Wednesday night
  through Friday night.

&&

.DISCUSSION...
Synoptic Setup:

Surface map is showing a low over northern Canada with a decent
pressure gradient over Montana this afternoon. This has lead to an
increase in W to SW winds that have bumped temps across the CWA above
normal with highs near 70 north to the upper 70s south.

Chinook arch clouds were quite thick this morning across the
region and are expected to gradually decrease as a moisture stream
from the northern Pacific pushes south slightly.

Wednesday into Friday: The jet stream near the US/Canadian border
will go from a zonal position to more of a W-NW orientation.
Disturbances in this fast flow could kick off a few showers
Thursday and Friday. Temps will be quite cool Thursday and should
be the coolest day in this forecast period.

Beyond Friday: Surface high pressure over the Canadian prairies
looks to be in place this weekend with a NW upper flow. This will
keep daytime temps slightly below normal.

Early next week, an upper ridge looks to move in from the west
while a surface low over NW Canada helps to push a milder Pacific
airmass into the area for above normal temps.

FORECAST CONFIDENCE & DEVIATIONS:
The chinook arch over the area today signaled that these will be
an occasional weather feature to watch until next Spring. Models
do not prog these very well and public perception may become
soured with our optimistic forecasts when these occur.

Therefore, blended Sky grids with NAM12 and CONSMOS. Otherwise,
going NBM looked good. TFJ

&&

.AVIATION...
LAST UPDATED: 1900Z

FLIGHT CAT RANGE: VFR

DISCUSSION: Mainly high level clouds into tonight will lower come
Wednesday morning then some clearing is expected. Minor LLWS is
possible this evening.

Surface winds will decrease by evening, then generally NW
Wednesday at 10-20 kts. TFJ

&&

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

$$

weather.gov/glasgow