455
FXUS65 KGGW 172004
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
204 PM MDT Thu Jul 17 2025

.DISCUSSION...

KEY MESSAGES:

1) Scattered showers and thunderstorms are expected this afternoon
through tonight. A few could be severe with large hail, damaging
winds, frequent lightning, and locally heavy rainfall.

2) A gradual warm up will continue into the upcoming weekend with
afternoon highs recovering into the 80s to around 90 by then.

3) Unsettled weather conditions will continue through the weekend
and next week with chances for thunderstorms at times.

WEATHER PATTERN OVERVIEW:

The main focus will be on the anticipation of strong to severe
thunderstorms later today. They are expected to move southeast
across the southwest half of the CWA early this evening. HREF
Updraft Helicity is indicating that these may contain large hail
especially over Phillips, Petroleum, Garfield, Dawson and Prairie
counties. But damaging winds and brief heavy rainfall will also be
threats.

Conditions are expected to settle down after their passage this
evening/tonight. Surface high pressure will move ontop of the area
Friday morning providing decreasing clouds.

An unseasonable cool and unsettled weather pattern will continue
into Saturday when the next round of showers and thunderstorms
develop over the area. Southeast surface winds will feed warmth
and humidity while an upper low drops in from western Canada. This
will help to generate more storms in the afternoon this time (more
than the evening). With CAPE over 1000 J/kg, hail and brief heavy
rain look again to be more of a threat that damaging winds. A
Marginal Risk for severe weather has been highlighted by SPC but
wouldn`t be surprised if this is upgraded as we draw closer to the
event.

An upper trough will remain in place over the Pacific Northwest
for the remainder of the period to bring unsettled conditions and
temperatures at or slightly below normal. The highest chance of
showers with the coolest temperatures looks to occur Tuesday.

FORECAST CONFIDENCE & DEVIATIONS:
Deviation from NBM was only made to pops into tonight, otherwise,
NBM numbers looked good through the period. TFJ

&&

.AVIATION...

LAST UPDATED: 2000Z

Expected Flight Category: VFR, but brief MVFR possible in
thunderstorms.

Synopsis: Scattered showers and thunderstorms will move southeast
and probably miss most of the TAF sites early this evening. These
storms could contain large hail, damaging winds, and locally
heavy rainfall. These storms could produce brief MVFR ceilings or
visibility.

Winds: Southeast winds will gradually decrease into the overnight
hours but expect them to be gusty and erratic in the vicinity of
any showers/thunderstorms this evening. Winds Friday are expected
to be variable at speeds less than 10 kts. TFJ

&&

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

$$

weather.gov/glasgow