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KEY MESSAGES

- Bitterly cold temperatures continue through this weekend with wind chills dropping as low as 50 below zero in the far NE corner of the state. A Cold Weather Advisory and Extreme Cold Warning remain in effect. - Temperatures warm to near normal early next week along with mostly dry conditions.

DISCUSSION

WEATHER PATTERN OVERVIEW:

An upper trough and arctic surface high pressure system is over the region. The coldest temperatures will continue to be in the northeast, with warmer temperatures in the southwest part of the area. The subzero temperatures will end for most of the area after Monday morning as the upper trough shifts further east. Until then, periods of wind chills of 40 below or colder are nearly certain for far northeast Montana through Sunday morning. Northwest winds and a weak disturbance over central Montana Saturday into Saturday night will allow for scattered snow showers, mostly when forced upslope. A half inch to an inch of snow is the most likely scenario for the Little Rockies and Petroleum county.

Temperatures will slowly moderate through next week as an upper ridge begins to affect the area, which will also limit chances for precipitation.

FORECAST CONFIDENCE & DEVIATIONS:

Some adjustments were made to the base forecast through Saturday for higher resolution winds and going with about the median of the NBM for temperatures, given a deterministic warm bias in the extreme cold.

There is high confidence of the placement of the Cold Weather Advisories and Extreme Cold Warnings and a substantial warmup after Sunday. There is moderate confidence for accumulating snow showers occurring on Saturday.

-JEZ

AVIATION

PATTERN: The cold arctic airmass is now moving through the region and will settle in through this weekend. Scattered clouds will increase overnight while ceilings lower to patchy MVFR on Saturday with a chance of flurries.

FLIGHT CONDITIONS: Even though MVFR to VFR conditions are expected, cold temperature impacts at all NE MT terminals will may cause icing problems and equipment failure due to exposure, especially during the late night through early morning hours.

GGW WATCHES/WARNINGS/ADVISORIES

Cold Weather Advisory until 1 PM MST Sunday for Central and Southeast Phillips-Central and Southern Valley-Dawson-Garfield- McCone-Northern Phillips-Prairie-Richland-Southwest Phillips- Wibaux.

Extreme Cold Warning until 1 PM MST Sunday for Daniels-Eastern Roosevelt-Northern Valley-Sheridan-Western Roosevelt.