724 FXUS65 KGGW 291833 AFDGGW Area Forecast Discussion National Weather Service Glasgow MT 1233 PM MDT Mon Jun 29 2026 .KEY MESSAGES... - Upper level low will bring showers and thunderstorms this afternoon and evening. - Upper trough lingers most of this week with chances for showers and thunderstorms at times. - Temperatures will gradually warm to near normal this weekend. && .DISCUSSION... WEATHER PATTERN OVERVIEW: An upper trough is over the area. A weak, slow moving trough in central Montana will bring a chance of showers and storms. Any storms that form will be slow moving, and with quite a bit of recent rain, hydrology will be important to watch in relation to flooding. There is a strong southerly jet over the east, so any thunderstorms that move through there have potential to drop wind gusts to 50 mph with small hail. An isolated storm has the potential to reach severe limits in this area with hail to one inch and winds to 58 mph, but odds are low for this scenario. There is heavy rain potential with any storm in this area, but training of storms is less likely than in central Montana. This activity is expected to be between 2 PM and 6 PM for the strongest storms, with weaker convection expected to last through midnight before ending. As the central Montana trough moves east tonight, winds are expected to pick up by the morning, and lingering cloud cover will allow for isolated showers and storms areawide in the afternoon. Precipitation accumulations are expected to be light tomorrow. After a brief shortwave ridge moves through on Wednesday morning, an active pattern appears to be on the horizon for Wednesday through Friday. There is a 5 percent chance of an isolated severe storm for Wednesday and Thursday, and a 10 percent chance on Friday. There is a decent shot of a ridge moving in after Friday according to the latest GFS ensemble, so temperatures are expected to warm up a bit closer to average this weekend. FORECAST CONFIDENCE & DEVIATIONS: The only deviation was PoPs for tomorrow and Wednesday night to fill in the gaps with at least a low precipitation chance. There is high confidence in precipitation and thunderstorm chances today and tomorrow, as well as in the Lake Wind Advisories that have been issued for Fort Peck Lake for today and tomorrow. There is moderate confidence in showers and storms occurring across the area for Wednesday and Thursday, and high confidence for Friday. There is moderate confidence in an isolated severe storm for Wednesday through Friday. && .AVIATION... UPDATED: 1830z Monday June 29th FLIGHT CATEGORY: VFR most of the time. Areas of MVFR in thunderstorms this afternoon and evening, as well as in the morning tomorrow. DISCUSSION: There is a trough over central Montana, as well as over western North Dakota. The troughs will begin moving east this evening, which well help aid in shower and storm activity from 20Z to 05Z Tuesday. The trough in central Montana suggests low clouds for a few locations in the morning. There is moderate to high confidence of MVFR ceilings for KOLF and KGGW from 13Z to 21Z Tuesday, and low confidence for KSDY and KGDV in that time frame. An isolated shower or storm is possible after 18Z Tuesday, so there is low confidence in MVFR conditions in thunderstorms then. WINDS: Variable at 10 to 15 knots, becoming southwest at 8 to 14 knots after 04Z, becoming west at 15 to 25 knots with gusts to 35 knots after 15Z Tuesday. && .GGW WATCHES/WARNINGS/ADVISORIES... Lake Wind Advisory until 6 PM MDT this evening for Central and Southeast Phillips-Central and Southern Valley-Garfield-McCone- Petroleum. Lake Wind Advisory from 6 AM to 8 PM MDT Tuesday for Central and Southeast Phillips-Central and Southern Valley-Garfield-McCone- Petroleum. && $$ weather.gov/glasgow