textproduct: Glasgow

DISCUSSION

KEY MESSAGES:

- Light snow will occur at times through the morning.

- Expect strong and gusty winds this morning. A High Wind Warning has been issued for SW Phillips, Prairie, Dawson, Wibaux Counties through 9AM. Blowing snow will be a problem through most of the day today.

- Bitter cold temperatures are expected between Thursday night and Sunday with wind chills as low as -40 Friday morning. An Extreme Cold Watch has been issued.

WEATHER PATTERN OVERVIEW: Overall steering flow remains from the northwest with a strong upper level low pressure center over central and eastern Canada and persistent high pressure anchored on the west coast of most of North America.

Today: Occasional embedded short-wave disturbances continue to ride NW flow over our region, bringing periods of light accumulating snow, which is expected this morning with a little bit of clearing this afternoon.

Also, a tight pressure gradient and disturbance will descend off the northern Rockies and sweep through eastern Montana. Model data indicate that gusts up to 60 mph will be possible for some locations, a High Wind Warning is in effect for SW Phillips, Prairie, Dawson and Wibaux Counties. A combination of the wind and snow could lead to blowing snow conditions and reduced visibilities. But there is high uncertainty in where and low visibility goes as it will depend on strengths of wind gusts and the extent of available new loose snow.

Thursday into Sunday: A much colder lobe of arctic air will sweep down through the Canadian prairie on Thursday, and allow temperatures for NE Montana to drop -20 degrees and wind chills to drop to around -40 degrees for some locations. Wind Chill Advisories are almost a given at this point. The question will be the extent of any needed Cold Warnings at the -40 break point. For this reason an Extreme Cold Watch has been issued.

Later this week and weekend: The center of the Arctic airmass drifts eastward into Quebec. Warming from the west is expected and a return to near normal temperatures for us, as the responsible ridge topples over a few times and shallows out the arctic air with a few weak Chinooks. However, details on how this happens is not yet known well in the ensemble set as breakdown on the synoptic level starts around Saturday. But, the bulk of solutions do remain warmer.

FORECAST CONFIDENCE & DEVIATIONS: Deviations from NBM include changes to hourly PoPs for the first 6 to 9 hours to move high PoP fields about one county farther west to keep up with radar trends.

Confidence is MODERATE to HIGH for strong and gusty winds to 60 mph for SW Phillips County

Confidence is MODERATE to HIGH in cold temperatures, through the weekend.

Confidence is HIGH for cold weather advisories through Saturday morning. The question will be, how deep and far west does the cold get for a warning.

/GAH

AVIATION

UPDATED: 0900Z

FLIGHT CAT RANGE: VFR - IFR

DISCUSSION: Multiple rounds of snow impacting NE MT TAF sites through the cycle. Most snow should end around 15-18Z. IFR will be possible anywhere snow occurs, otherwise MVFR ceilings will be the main categorical driver. Strong to high winds across the area will take any snow from the last 2 days and generate blowing snow conditions with visibilities dropping at times through the afternoon. How low is uncertain as it will depend on both the strength of wind gusts and the amount of loose snow that is available for any given location.

WIND: NW at 20 to 30 gust 45 kts this morning. Reducing to 15-25 gust 35 kts this afternoon. Further reducing to 10 to 20 kts this evening. Veering N after midnight through Thursday morning.

BEYOND THE CYCLE: Extreme cold with temps below 0*F is expected to enter the area Thursday night and last into Sunday morning. This will cause problems for some equipment and fuel O-rings.

GAH

GGW WATCHES/WARNINGS/ADVISORIES

Extreme Cold Watch from late tonight through Saturday morning for Central and Southern Valley-Daniels-Eastern Roosevelt- Northern Phillips-Northern Valley-Richland-Sheridan-Western Roosevelt.

High Wind Warning until 9 AM MST this morning for Dawson-Prairie- Wibaux.

High Wind Warning until 9 AM MST this morning for Southwest Phillips.