612
FXUS65 KGGW 180636
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
1236 AM MDT Tue Aug 18 2026

.KEY MESSAGES...

- Isolated to widely scattered thunderstorms are again expected
  Tuesday afternoon and evening, especially over the Little
  Rockies southeast toward Winnett and Jordan. A few may be
  severe.

- Temperatures look to warm up to near to above normal by the
  middle of the week as highs push back into the mid and upper
  80s.


&&

.DISCUSSION...

WEATHER PATTERN OVERVIEW:

The next shortwave trough will track through the region this
afternoon into tonight with convection initiation expected over
portions of Central Montana. These storms will then track into
portions of eastern Montana during the afternoon and evening
hours. For our CWA, focus will be especially over the Little
Rockies southeast toward Jordan and points southwest. This is also
where an isolated severe thunderstorm is possible. The SPC has
once again included a Marginal Risk outline. Meanwhile, HREF max
ensemble wind gust and updraft helicity signatures support our
southwestern zones in this perimeter.

Ensembles next depict height rises over NE Montana as the U.S.
Western CONUS upper level ridge becomes more amplified for the
second half of the week. Large scale subsidence will help keep
convective chances far more limited while temperatures begin an
upward ascension toward above normal readings with highs in the
mid to upper 80s for this period.

FORECAST CONFIDENCE & DEVIATIONS:

Pops were given a nudge in collaboration with neighbors as well as
to provide better areal continuity where thunderstorms are
expected for Tuesday. Otherwise NBM led the way with confidence
above average overall. The exception is toward severe
thunderstorms where confidence is more modest given the
expectation for limited coverage.


&&

.AVIATION...

LAST UPDATE: Tuesday August 18 at 0615Z.

FLIGHT CAT RANGE: VFR.

DISCUSSION: Skies will feature a few mid to high level clouds from
time to time. Otherwise look for thunderstorms that may edge
toward KGGW this evening with a tracking shortwave, though most
should remain to the west of area terminals.

WINDS: The expectation is for winds to remain light and variable
for the taf period, though strong and shifting winds gusting as
high as 60 mph are possible with isolated storms.


&&

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

$$

weather.gov/glasgow