101 FXUS65 KGGW 132145 AFDGGWArea Forecast Discussion National Weather Service Glasgow MT 345 PM MDT Sat Sep 13 2025
.DISCUSSION...
KEY MESSAGES:
1) Thunderstorm chances to continue this evening, a few may produce heavy rainfall.
2) The next significant chance for rainfall with showers and thunderstorms continues to take shape on Tuesday.
3) Overall expect temperatures near seasonable normals this upcoming week.
WEATHER PATTERN OVERVIEW:
Upper trough pattern in place will maintain thunderstorms through at least this evening. Locally heavy rainfall remains possible with some training and slow motion of the storms. The trough pushes east enough for Sunday that aside from isolated coverage most of NE Montana will remain dry.
The next Pacific trough will enter the scene across the northern Rockies, and merge with the lingering low over North Dakota. This will lend support to the next round of showers and thunderstorms.
Aside from precipitation chances, forecast temperatures are to remain near seasonable averages through the week.
FORECAST CONFIDENCE & DEVIATIONS:
NBM populated most of the forecast just fine with a few tweaks for consistency and collaboration. Confidence remains high on seasonable temperatures for the week ahead with precipitation chances at times. Confidence is more moderate on timing and precipitation amount for a given location given the nature of convection.
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.AVIATION... LAST UPDATE: 2130Z on 9/13/2025
FLIGHT CAT RANGE: Mostly VFR, some MVFR.
DISCUSSION: Isolated to widely scattered thunderstorms will continue through this evening before diminishing. Low ceilings and visibilities are possible with the storms.
WIND: Generally light and variable through the cycle. Becoming erratic and gusty near the stronger storms.
EQUIPMENT: NOTAM comms issues with the KSDY observation remain. AMD NOT SKED will remain in place until METARs are available.
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.GGW WATCHES/WARNINGS/ADVISORIES... None. &&
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weather.gov/glasgow
NWS GGW Office Area Forecast Discussion