textproduct: Glasgow

KEY MESSAGES

- Triple digit temperatures expected for Friday through Sunday. Extreme Heat Warnings are in effect for the 3 day period.

- Dry conditions most of the time but the could be an isolated thunderstorm Saturday evening.

- Drier and breezier conditions today and Saturday will increase fire weather concerns. A Red Flag Warning is in effect today.

DISCUSSION

WEATHER PATTERN OVERVIEW: An upper ridge over the western states will bring the heat back to the area through the weekend. A weak frontal system will help to bring west winds today.

Abundant smoke from the Pacific NW fires will move into the forecast area today with reduced visibility. Will mention haze in the forecast to account for this.

West winds will be strong enough this afternoon for a Lake Wind Advisory.

Will expand the Extreme Heat Warning to include all areas. It looks like Saturday will be the hottest day with highs above 100 in most areas and a few locations like Glendive and Terry above 105 for highs. Heat impact level maps are recommending an Extreme Heat Warning for all areas on Saturday. To keep the headlines simple, will include all areas today through Sunday in the warning. Flow aloft turns SW Saturday afternoon and evening while a shortwave trough and weak cold front brings a chance for showers and thunderstorms Saturday evening. Highs on Sunday will only be a few degrees cooler with highs near 100.

Will maintain Red Flag Warning for today. Will not include Saturday for now as winds are expected to be light. Fire weather issues may arise Sunday with higher winds and low humidity. However zones 136 and 137 may not have the wind to reach the criteria.

The upper ridge next week tries to push east but an upper trough over the eastern US keeps it at bay. Expect a slight cooldown but temps will remain above normal with mainly dry conditions.

FORECAST CONFIDENCE & DEVIATIONS: Low confidence that there will be a thunderstorm somewhere in northeast Montana tonight, based on HREF. High confidence on breezy west winds on Friday and on the heat this weekend.

AVIATION

FLIGHT CATEGORY: VFR most of the time. Smoke and haze may reduce visibility to MVFR at times.

Smoke from the Pacific Northwest will move into the area, dropping visibility at times today and tonight. Otherwise, skies will mostly clear with some mid and high clouds at times.

DENSITY ALTITUDE issues are expected at times with the heat today through Sunday at the terminals.

WINDS: Variable less than 10 knots early, becoming SW 5 to 10 knots between 09z and 12z and west 15 to 25 knots by 18z. West to NW winds will diminish to 5 to 10 knots this evening and become light and variable after 06z tonight.

GGW WATCHES/WARNINGS/ADVISORIES

Red Flag Warning from 10 AM this morning to 9 PM MDT this evening for Dawson/McCone/Prairie/Richland/Wibaux Counties- Northern Valley and Northern Phillips Counties-Southern Petroleum and Southern Garfield Counties-The Little Rockies-The Lower Missouri River Breaks including the Charles M Russell National Wildlife Refuge.

Extreme Heat Warning from 10 AM this morning to 10 PM MDT Sunday for Central and Southeast Phillips-Central and Southern Valley- Daniels-Dawson-Eastern Roosevelt-Garfield-McCone-Northern Phillips-Northern Valley-Petroleum-Prairie-Richland-Sheridan- Southwest Phillips-Western Roosevelt-Wibaux.

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