617
FXUS65 KGGW 171944
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
144 PM MDT Fri Jul 17 2026

.KEY MESSAGES...

- Upper ridging will keep above average temperatures in place
  through the weekend. On Sunday, an isolated 100 degree
  temperature is possible in the Yellowstone River Valley. Heat
  related effects are possible especially Saturday when the
  humidity is a factor.

- There is a low chance of thunderstorms through Sunday but timing
  amounts and placements are low confidence.

- A brief cooldown is expected Monday.



&&

.DISCUSSION...

WEATHER PATTERN OVERVIEW:

Upper ridging will continue to bring very warm temperatures to the
region through the weekend. Isolated triple digit heat is possible
in the Yellowstone corridor from Terry to Sidney. The heat could
bring Advisory effects Saturday with the added humidity.

Weak embedded shortwaves will continue to tap deep monsoonal
moisture to offer daily chances for thunderstorms. High
precipitable water values will mean any given storm could be a
prolific rainfall producer. In addition, the SPC has included the
western zones of Phillips and Petroleum Counties for today in a
marginal risk for severe thunderstorms but the latest CAMS are
showing low chances for our CWA, so could be a dry night.

Off and on chances for storms will continue through Sunday but we
could be too capped for anything to fire up. In other words,
confidence is quite low that anything will happen.

Nighttime fog chances will be low but winds might be too strong
for it`s formation.

On Monday, an upper low will drop southeast into south-central
Canada. This will bring a breezy day so a Lake Wind Advisory will
likely be needed. But it will feel refreshing for most.

The upper ridge returns next week and that will allow temps to
rebound back into the mid 80s to mid 90s by the end of the week.

FORECAST CONFIDENCE & DEVIATIONS:

Some massaging of pops were made to try to reflect what the CAMS
models were showing through Saturday morning. TFJ

&&

.AVIATION...

UPDATED: at 1945Z.

FLIGHT CATEGORY: VFR.

DISCUSSION: Dry weather conditions are expected through this
evening. Late tonight, isolated to scattered thunderstorms pushing
in from the west may lead to brief reductions in ceilings.

WIND: East to southeast winds will prevail at 5 to 15 kts most of
the time with occasional gusty conditions near any thunderstorms.



&&

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

$$

weather.gov/glasgow