textproduct: Glasgow

DISCUSSION

KEY MESSAGES: 1) Look for showers and thunderstorms at times today mainly along the Canadian border. The showers and thunderstorms will become widespread across NE Montana tonight. Isolated strong to severe thunderstorms are possible today and tonight with the best chance this evening.

2) Gusty northeast winds are expected starting this evening with a cold frontal passage. The gusty NE wind will continue overnight and Tuesday. A Lake Wind Advisory will be issued for Fort Peck Lake

3) Widespread wet weather and cooler temperatures look to be in place area wide late tonight through Wednesday. Total rainfall across the region will range between 0.50" and 1.00" for most locations with isolated higher totals.

WEATHER PATTERN OVERVIEW:

A frontal boundary looks to keep showers and thunderstorms confined to the Canadian border most of today. It will also provide a large temperature range between the upper 70s north and mid to upper 90s south for highs today. The front will move south as a cold front stating in the late afternoon and spread the showers and thunderstorms to the entire region this evening and tonight. Gusty NE winds are expected behind the front and a Lake Wind Advisory for Fort Peck Lake will be issued between 6 pm today and 6 pm Tuesday.

This evening, HREF max ensemble wind gust and max updraft helicity lend support for an isolated severe thunderstorm threat. Large hail and damaging winds would be primary concerns with the timing mainly after 4pm. Otherwise showers and thunderstorms will become widespread tonight through either Tuesday night or Wednesday. Heavy rainfall is possible in some areas. Most areas are looking at between 0.50 inch and one inch of rainfall from this evening. Tuesday and Wednesday will have much cooler temperatures.

An early look at ensembles support a return to near normal temperatures by the end of the week but with active weather continuing at times. FORECAST CONFIDENCE & DEVIATIONS:

Confidence is moderate to high that thunderstorm chances will increase across NE Montana today into Tuesday with widespread steady rainfall amounts. However, somewhat lower confidence exists on a severe weather potential due to the isolated nature of expected risk.

Increased winds speeds somewhat tonight as models frequently under forecast winds behind cold fronts. NBM was otherwise largely used for the forecast period which captured expected overall trends well for this cycle.

AVIATION

LAST UPDATED: 0815Z on July 14, 2025

FLIGHT CAT RANGE: VFR today and this evening transitioning to MVFR and IFR late tonight.

DISCUSSION: VFR conditions will continue today with mid and high level clouds at times. Most showers and thunderstorms today will remain north of the TAF sites although KGGW and KOLF could see an isolated shower or thunderstorm. A cold front that will quasi- stationary near the Canadian Border most of today will move south starting in the late afternoon and bring frequent showers and thunderstorms starting this evening and continuing into Tuesday. Low clouds will move into the area tonight behind the cold front with a mix of MVFR and IFR ceilings likely after 06Z. Winds: Look for east to NE winds at 5 to 15 knots this morning, becoming north at 5 to 15 kts this afternoon at KGDV while remaining NE at the other TAF Sites. NE winds will increase to 15 to 25 knots after 00z at all TAF Sites.

GGW WATCHES/WARNINGS/ADVISORIES

Lake Wind Advisory from 6 PM this evening to 6 PM MDT Tuesday for Central and Southeast Phillips-Central and Southern Valley- Garfield-McCone-Petroleum.