451
FXUS65 KGGW 051841
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
1241 PM MDT Fri Jun 5 2026

.KEY MESSAGES...

- A brief ridge and dry period will continue for today. There is a
  chance of a strong thunderstorm in the northwest tonight.

- There is confidence in strong to severe thunderstorms occurring
  tomorrow afternoon and evening.

- A second wave of showers and an isolated thunderstorm is
  expected for Sunday along with cooler temperatures. Some models
  indicate temperatures in the 40s in the afternoon.



&&

.DISCUSSION...

WEATHER PATTERN OVERVIEW:
A brief shortwave ridge is over the area today to bring dry
weather. Tonight a developing low pressure system and low level
jet at 850 millibars are expected to bring isolated to scattered
thunderstorms to the northern half of the area from midnight to 6
AM. The more agressive models try to bring isolated severe storms,
but there is a low probability of this scenario. The low pressure
system will be more developed tomorrow afternoon. Here are a few
of the scenarios. A few models show storms firing along a dry line
east of line from Opheim to Jordan. The main threat would be
damaging hail. Another scenario is storms fire up in the east, and
storms move in from the high terrain of central Montana to have
two separate areas of strong storms. The other scenario is that
storms fire up in the Bighorn Mountains of Wyoming and move into
the southeast part of the area. These storms would bring high
levels of wind (gusts up to 70 mph). Regardless, all models have
some type of severe thunderstorm activity occurring between about
4 PM and midnight.

On Sunday, some CAM models indicate wide differences from the
overall NBM. The latest NAMNEST model shows no thunderstorms and
just synoptic driven rain during the day and well below normal
temperatures. The HRW FV3 has warmer conditions and scattered
thunderstorms in the eastern half of the area. Then by the
afternoon, temperatures hit the low 40s with rain on wind on top
of that. If the storms on Saturday are strong enough, it would
wash out the atmosphere and Sunday would not have any strong storm
activity. Weaker storms would allow a better chance of storms to
occur on Sunday. Either way, there is a decent chance accumulating
rain occurring on Sunday.

The pattern appears to stay in southwest flow aloft after Sunday,
so next week is expected to have repeated chances for showers and
thunderstorms every day. Accumulating rain is expected with this
activity.

FORECAST CONFIDENCE & DEVIATIONS:
No deviations were made.

There is moderate confidence of thunderstorms occurring tonight in
the northwest part of the area. There is a low probability of
these storms being strong to severe.

There is high confidence of thunderstorms occurring between 4 PM
Saturday and midnight, with moderate confidence of them being
strong to severe.

There is high confidence on temperatures today and tomorrow, but
low confidence for Sunday based on high uncertainty in the post
frontal environment.

There is high confidence a Lake Wind Advisory will be needed for
Fort Peck Lake on Sunday afternoon and evening.

There is high confidence of scattered showers and storms occurring
for various parts of the area every day of next week.

&&

.AVIATION...
LAST UPDATED: Friday June 5, 2026 at 1830Z.

FLIGHT CAT RANGE: VFR.

DISCUSSION: Today will feature great flying weather with mostly
sunny skies unfolding and dry conditions. As a low pressure
system begins developing tonight, there allows moderate confidence
of an isolated thunderstorm moving through KOLF and KGGW. KSDY and
KGDV appear to be too far southeast to see these storms. There is
a low probability (5 percent) of the storms being strong to
severe, as well as for MVFR conditions to occur. This activity is
expected to be confined between 6Z and 12Z before VFR conditions
move in again. For mid to late afternoon on Saturday, there is
moderate confidence of MVFR conditions occurring with any strong
thunderstorms that occur.

WIND: Southwest at 8 to 15 knots, becoming light and variable
after 02Z Saturday, becoming east southeast at 10 to 20 knots
after 15Z.

&&

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

$$

weather.gov/glasgow