textproduct: Glasgow

KEY MESSAGES

- Periods of showers will continue today with thunderstorms becoming more numerous this afternoon and evening. Look for some of the storms to again produce heavy rainfall.

- The upper trough will maintain cooler temperatures across the region into Monday and Tuesday, with periods of rain showers and thunder continuing.

- The upper low will shift east by the middle of the week with drier and milder conditions.

DISCUSSION

WEATHER PATTERN OVERVIEW:

Periods of showers will continue today with thunderstorms yet again becoming more numerous this afternoon and evening. Some of the storms will be prolific rain makers with the latest HREF 3 hour max QPF guidance ranging from 1 to 3 inches across portions of NE Montana during this time. Forecast soundings show precipitable water values near climatological maximums. Surface dew points have been in the 50s and 60s and these soundings show moist conditions through the vertical. The storms have been tending to track along an axis of elongated low pressure situated over the area, tending to move from southeast to northwest and this will tend to continue for today.

This evening, as the surface low shifts east, winds will switch to the west and increase, with a Lake Wind Advisory set for Fort Peck Lake from noon today through 6 PM Monday.

For Monday and Tuesday the upper trough and closed low will remain anchored across the region with seasonably cool temperatures and continued chances for showers at times along with isolated thunder. By the middle of the week, ensembles want to push the low eastward with a shallow ridge moving in from the west. There is some timing divergence in the solutions however. Thus, will keep some pops in the forecast.

The next shortwave will quickly approach from the west by about Thursday evening with additional chances for showers and thunderstorms, continuing what looks to be a fairly active weather pattern.

FORECAST CONFIDENCE & DEVIATIONS:

NBM was largely followed this cycle. That said, POPS were adjusted for collaboration and consistency across the next few days.

Confidence remains high on wet weather over the next few days, though lesser confidence exists on the timing of the eastward push of the upper low. This brings into question some uncertainties on when exactly it might dry out. That said, by Wednesday evening, there is increasing probability for a narrow dry period to unfold before the next system marches in from the west.

AVIATION

Updated: Sunday May 31, 2026 at 0600Z.

FLIGHT CATEGORY: MVFR. Brief IFR possible in intense thunderstorm downpours.

DISCUSSION: Look for periods of showers today with thunderstorms becoming numerous this afternoon and evening. Once again, some of the storms may produce intense and persistent downpours.

WIND: Southeast winds this morning will range from 5 to 15 kts, shifting west this evening and increasing to a range of 15 to 25 kts, gusting to 35 kts.

GGW WATCHES/WARNINGS/ADVISORIES

Lake Wind Advisory from noon today to 6 PM MDT Monday for Central and Southeast Phillips-Central and Southern Valley- Garfield-McCone-Petroleum.