FXUS65 KGGW 181218

AFDGGW



Area Forecast Discussion

National Weather Service Glasgow MT

618 AM MDT Sat Jul 18 2026



.KEY MESSAGES...



- Upper ridging will keep above average temperatures in place

  through the weekend. 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 ridge over the western state will be knocked down slightly

by a shortwave/upper low pushing through western Canada through

the weekend. This wave will tap the 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 northwestern 

corner for today, and the southeast corner for Sunday in a 

marginal risk for severe thunderstorms but the latest CAMS are 

showing low chances for our CWA.



The hot temperatures will be shifting eastward through the

weekend, with temperatures dropping close to normal by Monday as

the shortwave moves east. 



The upper ridge returns next week and that will allow temps to

rebound to well above normal by the end of the week.



FORECAST CONFIDENCE & DEVIATIONS:



No significant deviations were made to the forecast. Confidence

for thunderstorms is generally low for much of the cwa through

Sunday.



&&



.AVIATION...

VFR. Isolated to scattered thunderstorms pushing in from the west

may lead to brief reductions in ceilings.







&&



.GGW WATCHES/WARNINGS/ADVISORIES...

None.

&&



$$



weather.gov/glasgow