textproduct: Glasgow

KEY MESSAGES

- Periods of showers look to continue today with thunderstorms becoming more widespread by the late afternoon and evening hours. Some storms may be slow moving, producing heavy rainfall.

- Upper trough will maintain cool and wet weather conditions across NE Montana into early next week.

- The trough will push east with drier conditions and moderating temperatures by the middle of next week.

DISCUSSION

WEATHER PATTERN OVERVIEW:

Periods of showers will continue at times today with thunderstorms becoming more numerous during the afternoon and evening hours. Overall, widespread wetting rains are expected from the numerous showers and thunderstorms. HREF guidance is showing 3 hour max QPF on the order of 1-1.5" with the heaviest slow moving convection this evening. The WPC maintains a slight risk of excessive rainfall for western portions of the CWA for this period.

The upper trough/closed low pattern will likely maintain wet and cool conditions over the region into early next week, with high temperatures for Sunday and Monday into the 60s for much of the weather. This will come as a relief from the recent hot and dry weather conditions across the area.

Ensembles show a general eastward progression of the trough such that a shallow ridge builds in for the middle of the week. This would allow drying conditions and moderating temperatures.

FORECAST CONFIDENCE & DEVIATIONS:

NBM was largely followed with a few exceptions. High temperatures were modestly nudged lower for the next couple of days. This is following the relatively recent warm bias in the NBM during the hot weather conditions. There is some degree of uncertainty whether or not this bias will persist with the pattern change.

Pops were also tweaked at times through the weekend for consistency and collaboration.

Confidence is above average for wet weather conditions and widespread wetting rains through early next week. While peak total rainfall amounts will likely come in between 1.5" and 3" through Monday, these may be isolated and confined to where slow moving storms persist. The exact timing and placement of these storms is difficult to pin down, but overall expect highest probabilities west of Glasgow to Jordan with lower probabilities toward the MT/ND border. Given dry conditions leading up to this event flooding concerns are minimal, but will have to monitor low lying areas, open fields, small streams, poor drainage areas where slow moving thunderstorms with intense downpours occur.

AVIATION

Updated: Saturday May 30, 2026 at 0545Z

FLIGHT CATEGORY: VFR to IFR. Brief IFR possible in intense thunderstorm downpours Saturday evening.

DISCUSSION: Periods of showers will continue today, with thunderstorms becoming more numerous in the evening hours. Some of the storms may produce intense and persistent downpours.

WIND: East at 10 to 15 kts, gusting to 25 kts. Gusty and shifting winds are possible with any storms.

GGW WATCHES/WARNINGS/ADVISORIES

None.