797 FXUS65 KGGW 162101 AFDGGWArea Forecast Discussion National Weather Service Glasgow MT 301 PM MDT Tue Sep 16 2025
.DISCUSSION...
KEY MESSAGES:
- Low pressure circulation will sweep through southern and eastern portions of our region today through Thursday
- Drier weather conditions will arrive from the west later this week, as temperatures remain seasonable.
WEATHER PATTERN OVERVIEW:
Split flow aloft is evident in regional satellite imagery as clouds stream from NE to SW near and northwest of Fort Peck Lake, and other clouds are advancing northward from SE Montana. The center of circulation over southern Wyoming is progged to slowly pinwheel eastward and northward eventually through the western Dakotas through Thursday. Best model agreement shows any resulting precipitation to be minimal and confined to areas either near or away from our southern and eastern periphery CWA zones. During this time frame, convective instability will also be on the decrease, reducing the threat for thunderstorms.
Beginning Thursday night, the weak ridge of high pressure approaching from the west will bring in drier and calmer conditions while keeping temperatures seasonably normal at least through the weekend if not longer.
FORECAST CONFIDENCE & DEVIATIONS:
PoPs and winds have been adjusted with hi-res models for Day 1 and 2 due to the lack of needed detail from the NBM.
Low confidence in the exact timing and placement of shower activity through tonight.
High confidence in the temperature forecast.
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.AVIATION...
UPDATE: 2059Z, 9/16
PATTERN: Migrating low pressure system from Wyoming will sweep up through the western Dakotas over the next few days. Some light rainfall is possible for KGDV and KSDY.
FLIGHT CONDITIONS: VFR, then an hour or two of MVFR if a shower happens to pass directly over KSDY or KGDV tonight.
WINDS: Generally light and variable, but erratic and gusty near the stronger storms this evening through tonight.
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