textproduct: Glasgow

KEY MESSAGES

- Isolated thunderstorms are expected to track in from the west this afternoon and evening, mainly west of a line extending through Opheim to Glasgow to Jordan.

- More scattered thunderstorms are expected Wednesday afternoon and evening, and an isolated storm may be on the stronger side with wind gusts to 50 mph. - Warmer temperatures are forecast for this weekend with highs in the 70s and 80s.

DISCUSSION

WEATHER PATTERN OVERVIEW:

An initial shortwave on northwest flow aloft tracking between the ridge to the west and trough to the east looks to provide enough dynamic support for isolated showers and thunderstorms this afternoon and evening. Much of this is expected to quickly diminish after sunset with little if any fanfare.

On Wednesday, a low pressure trough over central Montana will track east with a cold front pushing through eastern parts of the state. The HREF is supportive of a little more widespread convection between about 21Z and 03Z. The max ensemble wind gust guidance also suggests that a few of the storms may be capable of strong wind gusts to around 50 mph. The upper trough will slide east on Thursday with lingering showers and perhaps isolated thunderstorms. QPF overall will be light Wednesday and Thursday, though an isolated wetting rain is possible with the steadier more concentrated convection.

Ensembles are attempting to show a ridge pattern emerging over the weekend, though potentially still with embedded shortwaves. In general this will mean a warming trend though potentially with an isolated thunderstorm at times.

FORECAST CONFIDENCE & DEVIATIONS:

High resolution guidance was used for near term POPS with additional refinements for collaboration purposes. Some of the HREF members introduce convection a bit earlier into the afternoon on Wednesday, something future shifts may need to better account for. Otherwise, confidence is moderate to high on isolated to scattered coverage given model consensus. Ensemble spread increases toward the weekend with confidence increasing for the warm up, but less confidence exists on emerging precipitation chances at larger time scales due to ensemble spread, and shortwave timing.

AVIATION

LAST UPDATED: Tuesday May 19, 2026 at 1845Z

FLIGHT CAT RANGE: VFR.

DISCUSSION: Mostly sunny skies are expected to start out though look for increasing cumulus cloud and high cirrus this evening as isolated thunderstorms remain mainly west of area terminals.

WIND: Winds will be south to southeast this afternoon and evening at 10 to 15 kts, diminishing to around 10 kts or less after 03Z.

GGW WATCHES/WARNINGS/ADVISORIES

None.