483
FXUS65 KGGW 181934
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
134 PM MDT Fri Jul 18 2025

.DISCUSSION...

KEY MESSAGES:

- After dry conditions today, thunderstorms will return Saturday
  with the possibility of them being severe especially in the
  central and eastern zones.

- A gradual warm up will continue into the upcoming weekend with
  afternoon highs recovering into the 80s.

WEATHER PATTERN OVERVIEW:
A generally zonal pattern will continue over the northern part of
the country over the next week. But an upper low over British
Columbia will drop a bit tonight and Saturday that will help
destabilize things over eastern Montana. Southeast winds Saturday
look to encroach on advisory speeds so went ahead and issued a
Lake Wind Advisory (plus there are planned activities).

Another concern will be the potential for strong to severe
thunderstorms as a warm and unstable airmass will be in place.
Dewpoints in the mid 50s to mid 60s will add fuel to the fire as
well and a surface boundary moving through the area may provide
good focusing for these storms as well.

Dewpoints in the 60s are expected to linger over the eastern zones
Sunday but surface boundary may push into western ND while the
upper low provides decent upper level shear/dynamics.

Afterwards, southwest flow aloft will deepen, along with a
potential link with monsoonal moisture, for thunderstorms
increasing on Tuesday. Temperatures will cool as the upper trough
moves through the region midweek.

FORECAST CONFIDENCE & DEVIATIONS:
Deviation from NBM was only made to winds through Saturday, bumped
them closer to NBM90. Otherwise, NBM numbers looked good through
the period. TFJ

&&

.AVIATION...
UPDATED: 2000Z

FLIGHT CONDITIONS: VFR, but could lower Saturday in places.

DISCUSSION: VFR clouds this afternoon will linger into Saturday
morning, however lower clouds could move in from the S-SE Saturday
morning with MVFR ceilings possible. Afternoon
showers/thunderstorms Saturday could also bring MVFR conditions.

WINDS: Increase from the SE tonight and into Saturday peaking at
speeds of 15-20 kts with some higher gusts. Winds decrease
Saturday evening. TFJ

&&

.GGW WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory from 6 AM to 6 PM MDT Saturday for Central
and Southeast Phillips-Central and Southern Valley-Garfield-
McCone-Petroleum.

&&

$$

weather.gov/glasgow