Nashua, Montana Weather Forecast Discussion

621
FXUS65 KGGW 172141
AFDGGW
Area Forecast Discussion
National Weather Service Glasgow MT
341 PM MDT Wed Sep 17 2025
.DISCUSSION...
KEY MESSAGES:
- The complex Low pressure circulation will sweep through southern
  and eastern portions of our region through Thursday with off-
  and-on chances for rain along the MT/ND boarder.
- Drier weather conditions will arrive from the west over the
  weekend with warming temperatures.
WEATHER PATTERN OVERVIEW:
The low pressure complex is starting to finally morph into one
single circulation, the center of which is now moving northward
through South Dakota. A NW outer band of isolated thunderstorms is
moving through our Big Sheep Mountains/Yellowstone River valley
areas today. The only two models which had this correctly pinned
were the hi-res FV3 and the GFS. So, I leaned on these two models
for blending the near term precip forecast. Tonight through
Thursday will see this system pinwheel up and through North Dakota
and spill off some back-door / wrap-around rain for our CWA
through Friday.
Saturday through Monday, a new western states ridge of high
pressure will moving into our region, bringing warmer than average
temperatures and much drier conditions. It will be wise to monitor
early next week for marginal fire weather conditions.
FORECAST CONFIDENCE & DEVIATIONS:
Deviated from the given NBM for Days 1 through 2, using a blend of
the hi-res FV3 and GFS models which more accurately reflected
reality today.
Confidence is average for precipitation timing, and amounts.
Confidence is high for the temperature forecast.
&&
.AVIATION...
UPDATE: 2135Z, 9/17
FLIGHT CAT RANGE: Mainly VFR, but thunderstorms and low clouds
may bring IFR conditions to KGDV and KSDY tonight through
tomorrow.
DISCUSSION: The entire region remains under the influence of a
migrating low pressure system. Expect low clouds and precipitation
to encroach westward from North Dakota into NE Montana toward the
latter half of this TAF cycle.
WIND: Generally light and variable if not calm this afternoon and
evening, then setting up from the ESE around 10 kts tomorrow.
EQUIPMENT: Comms issues with the KSDY observation remain. AMD NOT
SKED will remain in place until METARs are available.
&&
.GGW WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
weather.gov/glasgow

NWS GGW Office Area Forecast Discussion