textproduct: Glasgow

KEY MESSAGES

- This morning will be cold across northeast Montana, with chances for near record lows if clouds clear out overnight.

- Wednesday afternoon into Thursday morning looks like the next chance for showers and perhaps and few thunderstorms. Most areas that would be hit look to have less than a tenth of an inch.

- Warm weather returns briefly Wednesday with 70s & 80s for highs expected Friday onward.

DISCUSSION

WEATHER PATTERN OVERVIEW: Forecast begins with a large cold airmass over the Hudson Bay. a trough runs west out of it and down through southern Canadian Prairie Provinces and eastern Montana, and terminates over northern Utah. An equally amplified ridge runs from northern California the PCNW, Alberta, and terminates over the Northwest Territories.

This morning through tonight: Conditions will start off cool with a ground freeze initially as clear skies hover over the area. By the late afternoon a new round of mid to upper chinook arch clouds will move in from the west along with slightly warmer temps under the highly amplified ridge.

Wednesday into Thursday Morning: Ridge will exit the area as a shortwave begins to drive itself down in northwestern flow. as the ridge breaks down a low pressure surface trough will form over central Montana mid day. by the late afternoon and early evening hours this will move into eastern montana along a cold front with rain showers and perhaps a few thunderstorms. Most storms should exit overnight with the heat leaving rain showers to linger into Thursday morning. QPF totals are in flux currently unknown but generally a tenth of an inch or less is expected for this passage.

Thursday afternoon into the weekend: Conditions will clear and warm through these time periods with maybe a weak shower possible Saturday night with ensemble breakdown occuring about this point forward making confidence from Saturday onward LOW.

FORECAST CONFIDENCE & DEVIATIONS: Changes to NBM were focused to hourly PoPs around Wednesday mid- day to the evening. Hourly NBM data was being direct interpolated in the last 5 hours. Used and NPoP blend of available CAMs to try to quick blend in a slightly better trend.

GAH

AVIATION

LAST UPDATED: 0330Z

FLIGHT CAT RANGE: VFR.

DISCUSSION: Overcast conditions across the east this evening are expected to exit the area by the early morning hours. A few isolated fog pockets may be possible northeast of KOLF and KSDY as clouds clear but should not impact the main terminals directly tonight. Sun-up conditions should be SKC but mid to high clouds will begin approaching the area from the west late Tuesday afternoon early evening.

WIND: Light and variable tonight. Becoming S to SW after sun-up and increasing to 5 to 15 kts through Tuesday. Backing S to SE Tuesday evening.

GAH

GGW WATCHES/WARNINGS/ADVISORIES

None.