textproduct: Glasgow

KEY MESSAGES

- Arctic air remains over the area through tonight.

- Much warmer temperatures last Sunday through Wednesday.

- The next frontal system with precipitation arrives midweek.

DISCUSSION

WEATHER PATTERN OVERVIEW:

The Arctic air in place begins to retreat later tonight, but will still produce winds chills around 25 below or colder for the northeast corner of Montana where a Cold Weather Advisory remains. Portions of this area have remained below zero since Thursday evening with wind chills in the 20s below this afternoon. Lake effect clouds and flurries have came off of Fort Peck Lake and will continue to impact Fort Peck to Glasgow through at least this evening given little change to winds and temperatures.

On 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 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 early Sunday morning. Confidence past the warmer than normal temperatures through Wednesday is low for NE Montana being on the edge of another Arctic airmass. Made slight adjustments to winds, sky and temperatures through Sunday to account for local effects from steam off Fort Peck Lake and lingering inversion in the Milk/Missouri River Valleys.

-JEZ

AVIATION

LAST UPDATED: 2130Z

FLIGHT CAT RANGE: Mostly VFR, patchy IFR/MVFR around KGGW

DISCUSSION: With southeast winds and subzero air passing over Fort Peck Lake, there is high confidence for continued localized areas of MVFR-IFR and patchy flurries into tonight for KGGW from broken low cloud development. Warming temperatures and shifting winds likely eliminate this impact to KGGW by 15Z. Below zero temperatures remain in place into early Sunday morning.

WINDS: Southeast at 10 to 15 knots, becoming west around 10 knots after 15Z.

GGW WATCHES/WARNINGS/ADVISORIES

Cold Weather Advisory until 6 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.