textproduct: Glasgow

KEY MESSAGES

- Winter Weather Advisories remain in effect until noon Monday for Northern Phillips, Northern Valley, and Southwest Phillips Counties.

- Precipitation will continue through tonight and move eastward out of the region Monday night. Much of the area can expect half an inch to an inch of additional rainfall with lower amounts in Wibaux and southeast Prairie Counties. - Snow accumulations remain more likely in northwestern zones along the Canadian border and in higher elevations of the Little Rockies.

DISCUSSION

An upper-level low continues to linger over the Pacific Northwest tonight, providing ample Pacific moisture transport into the region via southwest flow aloft. Winter weather impacts have already been observed across Billings and Great Falls where heavy snowfall has accumulated over highways.

Across the Glasgow CWA, rainfall is still being observed and timing on a rain-to-snow transition is uncertain, especially across lower elevations. Temperatures have trended slightly cooler than originally forecasted, so it is possible for precipitation to start mixing earlier than previous forecast guidance. Meanwhile, anticipated snowfall totals may be heightened especially in high elevations of the Little Rockies and along the Canadian border. Area cameras snow accumulating snow on Highway 191 south of Malta near Zortman this evening. Confidence remains below average on forecast accumulations due to a wide range expected due to differences in elevation as well as marginal thermal profiles.

Forecast QPF totals have continued to trend upward, and much of the region can anticipate half an inch to an inch of additional rainfall. Wibaux and southeastern Prairie Counties should remain on the drier side with rainfall amounts up to 0.50" possible. Snow accumulation will remain more concentrated in areas described above, while lower elevations may struggle to accumulate much snow due to warm ground temperatures. Winter Weather Advisories remain in effect until noon Monday for Southwest Phillips, Northern Phillips, and Northern Valley Counties as a result.

Temperatures remain well below average tomorrow before gradually warming up by the end of the week. An upper-level cutoff low will develop over the Four Corners region and advect warmer air into Northeast Montana.

FORECAST CONFIDENCE & DEVIATIONS:

Confidence of below average temperatures through Monday remain high. There is moderate confidence in a gradual temperature climb throughout the week, but uncertain on exact temperature profiles. Chances of additional precipitation later in the week will depend on the track of the system over the Four Corners.

While confidence in QPF amounts have trended higher, precipitation type, timing, and snow accumulation remain below average. Evaporative cooling effects have likely contributed to cooler- than-forecasted temperatures, but warm ground temperatures still remain and will prevent much accumulation in lower elevations.

Model agreement deteriorates drastically beyond Wednesday, so confidence remains low for weather conditions mid- week onward.

KENZ

AVIATION

LAST UPDATED: 0445Z

FLIGHT CAT RANGE: IFR conditions through the TAF cycle.

Discussion: Periods of rain, potentially mixing with wet snow will continue across area terminals through 18Z Monday. Patchy fog is possible at times as well. Associated visibility reductions and low ceilings will lead to IFR conditions through the period. IN

Winds: NE at 10 to 15 kts, becoming light and variable Monday afternoon and evening.

GGW WATCHES/WARNINGS/ADVISORIES

Winter Weather Advisory until noon MDT Monday for Northern Phillips-Northern Valley-Southwest Phillips.