378
FXUS65 KGGW 180601
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
1201 AM MDT Fri Sep 18 2026

.KEY MESSAGES...
- Temperatures remain warm through Friday then cooler than average
  temperatures are expected Saturday and Sunday into the mid 60s
  trending towards lower 60s on Sunday. Warmer temperatures are
  anticipated to return to the region next week.

- Chances of widespread showers return Friday night into Saturday.
  Embedded thunderstorms possible.


&&

.DISCUSSION...
SYNOPTIC SETUP:
An low pressure system moving south into northern California cut
off by the northern stream will continue to lift northeast over
the next several days. Ahead of it, a ridge will depart the
northern High Plains early this morning for North Dakota and
southeast low level flow will continue with breezy conditions.

As with the last round of ensemble data, the latest guidance is a
bit further south with the storm track and shows a tight gradient
in precipitation amounts over our northern CWA. Although, any
embedded convective elements that concentrate may raise totals
locally. The NBM generally gives 0.5" to 1.5" of total QPF with
the heaviest corridor south of the Missouri River and west of the
Yellowstone River. Lesser rainfall amounts are expected toward the
Canadian border and MT/ND border. Look for showers to become most
widespread Friday night and Saturday before the system slowly
exits Sunday. The Weather Prediction Center has highlighted a
marginal risk of excessive rainfall for late today through
Saturday.

Upper ridging will yield drier and warmer conditions for early
next week. Those conditions then look to hold steady through the
end of the work week.


FORECAST CONFIDENCE & DEVIATIONS:
Meanwhile, confidence is below average for this upcoming
precipitation event for Friday into Saturday given poor run to run
continuity among the guidance, a trend toward the south, and a
tight gradient over NE Montana. To that end, widespread rainfall
ranging from 0.25" in the north to 1.00" in the south and
southwest are still largely most likely, with the highest totals
south of the Missouri River and west of the Yellowstone River,
concentrated over SW Phillips, Petroleum, and Garfield Counties.

/GAH


&&

.AVIATION...
LAST UPDATED: 0530Z

FLIGHT CAT RANGE: VFR

DISCUSSION: VFR conditions will hold through through today and
into most of tonight. About 12Z Saturday morning just after the
cycle clouds will begin to lower to MVFR and possibly IFR. Light
rain showers will begin impacting the terminals a little earlier
around 06Z tonight and become more widespread into Saturday
morning. Brief MVFR visibility may be possible in the heaviest
rain showers or embedded storms by mid-day Saturday.

SFC WIND: S to E at 5 to 10 kts through noon. Becoming N to NE
Friday afternoon and through Friday night. Veering E Saturday
morning.

GAH


&&

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


&&

$$

weather.gov/glasgow