614
FXUS65 KGGW 211949
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
149 PM MDT Mon Jul 21 2025

.DISCUSSION...

KEY MESSAGES:

- Expect another round of thunderstorms tonight, some could be
  severe as they move northeast. Significant rainfall between
  0.25" and 0.75" is expected area wide through Tuesday with
  isolated higher totals.

- Cooler temperatures and continued unsettled weather conditions
will continue into the midweek.

- Warm and dry weather will return late in the week or this
weekend as upper ridging once again builds across the region.

WEATHER PATTERN OVERVIEW:
Southwest flow this afternoon is in place ahead of an upper trough
over the Pacific Northwest. Scattered showers have developed in
the cumulus field from south-central Montana south into eastern
Idaho that will intensify with further heating. A theta-e ridge is
building again over eastern Montana which should help the
scattered showers over northern Wyoming to continue building as
they move northeast. These showers should move through the SE
zones with activity over eastern Idaho to move into the CWA later
this evening. The 12z HREF has backed off a bit on updraft
helicity but the central and southeast portions of the CWA should
see hail and brief heavy rain (especially the eastern zones later
tonight) with some possibility for damaging wind as well.

An upper trough over the Pacific NW will keep the SW flow aloft
over the CWA again tomorrow, but with cooler temps, severe
thunderstorms look to be mainly to our south.

Cool conditions linger into Wednesday again then the upper trough
begins lifting out for some warmer conditions later in the week.

Mainly dry conditions are expected but a disturbance may bring
back a chance of thunderstorms over the weekend. TFJ

FORECAST CONFIDENCE & DEVIATIONS:

Minor tweaks to pops were made otherwise NBM followed for the base
population. Confidence is high for thunderstorms tonight and
unsettled weather through the midweek and above average for the
return to warm and dry weather late week.

&&

.AVIATION...

Updated: 1950Z

FLIGHT CONDITIONS:
VFR conditions will generally prevail into the evening though as
thunderstorms become more common, expect MVFR ceilings with
visibilities down to IFR by late tonight into Tuesday.

WINDS: Northeast tonight at 5 to 15 kts, then light East Tuesday.
Expect strong gusty and shifting winds near thunderstorms
tonight. TFJ

&&

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

$$

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