textproduct: Glasgow

KEY MESSAGES

- Another strong winter storm with significant snow accumulation for portions of the area continues through tomorrow morning. - Arctic air remains over the area through Saturday night with wind chills as low as the 30s below.

- Much warmer temperatures arrive on Sunday.

DISCUSSION

WEATHER PATTERN OVERVIEW:

Headline hazard products have been maintained to cover significant snow accumulations through early Saturday morning and dangerous wind chills through early Sunday morning. The area remains on the periphery of an upper level trough and surface arctic high pressure system, keeping a Cold Weather Advisory for the Hi-Line to along the North Dakota border, with minimal recovery until Sunday morning. The pattern and observations so far today remain favorable for widespread moisture riding up and over the northern Rockies to produce 4-9"+ snow totals for the majority of northeast Montana, with isolated higher amounts in banding for the Little Rockies and points southeast. Activity will gradually diminish and push toward the southeast late tonight.

By Sunday warmer high pressure pushes in from the west with substantial temperature recovery being aided by a chinook event off the east side of the northern Rockies. The warm up will be at least initially be limited due to the heavy snow cover in place, particularly in the Milk and Missouri river valleys. However, the winds justify mixing down of above freezing temperatures by Monday afternoon throughout the area. Potential hazards to watch for with this chinook pattern next week will be high winds in the Little Rockies, as well as fog and minor flooding from snow melt.

FORECAST CONFIDENCE & DEVIATIONS:

There is high confidence in wind chills remaining below zero through Sunday morning. Confidence is high in general snow totals and placement through Saturday morning, though lesser for the northeast edge heading toward Plentywood. Made slight adjustments to winds and temperatures through Sunday to account for more extreme cold with the Arctic airmass and challenges of mixing out of inversion Sunday given low confidence for above freezing temperatures at lower elevations then.

-JEZ

AVIATION

LAST UPDATED: 2130Z

FLIGHT CAT RANGE: LIFR to VFR

DISCUSSION: A very strong winter storm system with multiple impacts will persist through this weekend, though the greatest amounts will be southwest of the TAF sites. MVFR to VFR ceilings will continue through Saturday morning. IFR to LIFR visibility from a new round of snow is still expected to creep into the terminals between 22 to 02Z this afternoon/evening and will hold steady until about 12Z Saturday. There is moderate confidence of visibility down to 1/2 mile in snow, but around 1 mile will be more common. Extreme cold remains in place through Saturday night with subzero temperatures all or most of time.

GGW WATCHES/WARNINGS/ADVISORIES

Cold Weather Advisory until 7 AM MST Sunday for Central and Southeast Phillips-Central and Southern Valley-Daniels-Dawson- Eastern Roosevelt-McCone-Northern Phillips-Northern Valley- Richland-Sheridan-Western Roosevelt-Wibaux.

Winter Storm Warning until 8 AM MST Saturday for Central and Southeast Phillips-Central and Southern Valley-Dawson-Garfield- McCone-Northern Phillips-Petroleum-Prairie-Southwest Phillips- Wibaux.

Winter Weather Advisory until 8 AM MST Saturday for Daniels- Eastern Roosevelt-Northern Valley-Richland-Western Roosevelt.