500
FXUS65 KGGW 181814
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
1214 PM MDT Tue Aug 18 2026

.KEY MESSAGES...

- Isolated showers and thunderstorms are expected across mainly
  the western and central zones through the evening. One or two
  could be strong to severe.

- Another round of thunderstorms are expected Saturday night with
  S-SW monsoonal flow.

- Typical mid to late August conditions are expected over the next
  7 days with very warm daytime conditions and comfortable nights.


&&

.DISCUSSION...

WEATHER PATTERN OVERVIEW:

The next disturbance has kicked off showers and thunderstorms
over central Montana that were moving east into the CWA this
afternoon. There is a Marginal risk of severe weather with these
but HREF is showing most of the activity to be south of the CWA.
16z HRRR is showing current showers/thunderstorms to dissipate
then refire this afternoon over central Montana that`ll move
southeast this evening. Upper levels look to support these as they
move east overnight but loss of daytime heating should diminish
their severity.

Then the upper ridge builds over the Rockies from the Four Corners
area. This should suppress thunderstorm activity while
temperatures tick up a bit.

A disturbance in a monsoonal flow from the south is expected to
make it`s way into the area late Saturday. Expect an increase in
thunderstorms Saturday night. Expect a slight risk of heavy rain
and gusty winds when they move northeast through the area.

Warmer and dry conditions are expected to return Sunday. With
little wind expected, fire weather concerns are not expected to be
too high.

FORECAST CONFIDENCE & DEVIATIONS:

Pops were given a nudge in collaboration with neighbors as well as
to provide better areal continuity where thunderstorms are
expected through tonight. Otherwise, the NBM was given the royal
treatment. TFJ


&&

.AVIATION...
LAST UPDATE: 1815Z.

FLIGHT CAT RANGE: VFR.

DISCUSSION: Any thunderstorms late today are expected to diminish
as they move east toward the TAF sites tonight. KGGW stands the
best chance of being affected.

Winds are expected to be light and variable but could be gusty
and erratic in the vicinity of any shower or thunderstorm. TFJ


&&

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

$$

weather.gov/glasgow