144
FXUS65 KGGW 180809
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
209 AM MDT Mon Aug 18 2025

.DISCUSSION...

KEY MESSAGES:
- Upper ridge will warm temperatures to near 100 or higher Tuesday
  and Wednesday. Heat Advisory will be issued for Tuesday and
  Wednesday for all of northeast Montana.

- Cold front Wednesday night will bring chances for showers and
  thunderstorms that will continue into Thursday with much cooler
  temperatures for the remainder of the week.

WEATHER PATTERN OVERVIEW:

Showers and thunderstorms along and east of the Yellowstone River
early this morning will move to the east shortly after sunrise
this morning.

Upper ridge will build over Montana today and peak over eastern
Montana Tuesday and Tuesday night before moving to the east on
Wednesday.

Tuesday will likely be the hottest day in most areas and Wednesday
will be the hottest day in the east near the North Dakota border
for highs on Wednesday. Low temperatures for Tuesday night are
expected to between mid 60s to lower 70s. Will issue a long
duration Heat Advisory that covers both Tuesday and Wednesday.
Going forecast highs are near the NBM 50 at this point. The NBM
90 has highs near 110 in many areas on Wednesday which is either
near or higher than the all time record high for August at many
locations.

A cold front Wednesday night will bring much cooler temperatures
for the remainder of the week. There will also be chances for
showers Wednesday night and Thursday.

FORECAST CONFIDENCE & DEVIATIONS:
Main forecast deviation from the NBM was raise forecast highs
Tuesday and Wednesday closer to the NBM 50.

Confidence is high in very hot temperatures on Tuesday and
Wednesday which will exceed 100 degrees in many areas.

Low confidence in precipitation chances Wednesday night and
Thursday.

&&

.AVIATION...

LAST UPDATED: 0815Z

FLIGHT CAT RANGE: VFR

DISCUSSION:

Showers and thunderstorms along and east of the Yellowstone River
will move to the east by 12z this morning. Mid and high clouds
over eastern Montana overnight will clear this morning. Skies
will be mostly clear today and tonight with a few mid and high
clouds at times.

WIND: Variable less than 10 knots today and east to NE at 10 knots
or less tonight.

&&

.GGW WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 10 AM Tuesday to 8 PM MDT Wednesday for
Central and Southeast Phillips-Central and Southern Valley-
Daniels-Dawson-Eastern Roosevelt-Garfield-McCone-Northern
Phillips-Northern Valley-Petroleum-Prairie-Richland-Sheridan-
Southwest Phillips-Western Roosevelt-Wibaux.

&&

$$

weather.gov/glasgow