388
FXUS65 KGGW 170839
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
239 AM 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:

As temperatures warm starting today a renewed focus will be on
afternoon and nighttime thunderstorm potential. HREF updraft
helicity and ensemble max wind gust forecasts between 21-06Z
coincide nicely with the SPC DAY 1 outlook for severe storms. The
primary threat will be large hail, damaging winds, frequent
lightning, and heavy rainfall.

Meanwhile, a short ridge will keep the warm up going into the
weekend but progressive flow will keep thunderstorm chances into
the forecast. This is especially true Saturday afternoon into
Sunday as the ridge axis slides east of the CWA.

Ensembles then point to near seasonable average temperatures and a
continuation of thunderstorm chances into next week.


FORECAST CONFIDENCE & DEVIATIONS:

Confidence is moderate for thunderstorms this afternoon and
evening, lowered only by expected coverage and uncertainties with
timing and placement. High confidence exists with regard to the
expected warm up through the weekend. NBM was used this forecast
cycle with some adjustments to near term pops made for expected
trends and consistency.


&&

.AVIATION...

LAST UPDATED: 0830Z on July 17, 2025

Expected Flight Category: VFR, But IFR/MVFR possible in
thunderstorms.

Synopsis: Warmer temperatures will begin over the area tonight
with afternoon and evening thunderstorms. Some of the storms could
be severe with large hail, damaging winds, and locally heavy
rainfall. These storms could come with MVFR ceilings and
visibility down to IFR.

Winds: Southeast at 5 to 10 kts, increasing to 10 to 20 kts late
morning into the afternoon hours. Gusty and shifting winds may
occur with thunderstorms - timing 21Z-06Z.

&&

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

$$

weather.gov/glasgow