textproduct: Great Falls

KEY MESSAGES

- Bitter cold continues through Thursday morning across the Northern Plains.

- Light mountain snow expected through Friday with minimal impacts expected.

- Temperatures will warm up slightly this weekend with drier conditions expected to persist through Sunday.

DISCUSSION

- Meteorological Overview:

The worst of the bitter cold is expected to end by Thursday afternoon with high temperatures expected to rise above zero for the Northern Plains. Light snow will slowly taper off this morning across the region with some lingering mountain snow possible along the higher elevations of Southwest Montana.

Towards the weekend, upper-level ridging starts to build over the western CONUS allowing for temperatures to warm up slightly across the region with generally dry conditions expected to persist through Sunday. A return to a more active pattern is possible Monday and Tuesday as another shortwave moves across the region. There is a potential for some convective snowbanding to occur, particularly across Southwest Montana although the details remain uncertain at this time.

- Forecast Confidence & Scenarios:

Bitter Cold Tonight:

With clouds clearing across portions of central and north-central Montana, temperatures have begun to plummet below what was previously expected. So overnight lows have been appropriately lowered to account for this. When it comes to wind chill temperatures, wind speeds have been very light across the region so there is decent confidence that wind chills will stay within advisory levels through the night. Because of this, no zones will be added to a warning at this time. The coldest temperatures and wind chills are expected along the Rocky Mountain Front and across the Hi-Line.

Temperatures are still expected to warm up to the single digits above zero Thursday afternoon which will provide some relief from the worst of the bitter cold. From here, temperatures will gradually warm through the weekend. There is some uncertainty as to whether temperatures will warm up quite to the extent that the medium-range models have but, for now, the next best chance for above freezing temperatures across the northern plains will be on Monday.

Snowfall Thursday/Friday:

Light snow is expected to continue over the next few hours across Fergus county and the lower elevations of Judith Basin county. The Winter Weather Advisory will be allowed to continue for now as snowfall amounts are still expected to reach advisory-level impacts. Otherwise, snow will taper off across our eastern zones heading through the night with clearing skies following through the day on Thursday.

In the mountains, light snow showers are expected through Friday. Snowfall accumulations are expected to remain generally less than 2 inches with higher amounts staying well above pass level. As such, no additional advisories will be issued for the mountains at this time. -thor

AVIATION

19/00Z TAF Period

Light snow continues to affect much of North Central and Southwest MT early this evening. This area of snow is moving to the northeast and should move into the Havre area shortly. Overall the light snow will begin to slowly end after from south to north after 03z this evening. Expect low ceilings over much of the CWA until mid afternoon Thur before drier air slowly starts to move in from the west. Mountains/passes will be obscured across much of the CWA until mid afternoon Thu. Brusda

PRELIMINARY POINT TEMPS/POPS

GTF -2 -14 12 -3 / 50 60 10 0 CTB -7 -19 9 -6 / 40 20 0 0 HLN 2 -7 21 5 / 60 40 0 0 BZN 17 -2 23 3 / 60 60 10 0 WYS 30 -1 20 -11 / 90 70 50 20 DLN 25 5 28 7 / 50 50 10 10 HVR -1 -14 8 -8 / 10 60 40 0 LWT 1 -10 12 -2 / 40 80 40 0

TFX WATCHES/WARNINGS/ADVISORIES

Cold Weather Advisory until noon MST Thursday for Bears Paw Mountains and Southern Blaine-Cascade County below 5000ft-East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera-Eastern Pondera and Eastern Teton-Eastern Toole and Liberty-Fergus County below 4500ft-Gates of the Mountains-Hill County-Judith Basin County and Judith Gap-Northern Blaine County- Northern High Plains-Snowy and Judith Mountains-Southern High Plains-Southern Rocky Mountain Front-Upper Blackfoot and MacDonald Pass-Western and Central Chouteau County.

Winter Weather Advisory until 6 AM MST Thursday for Fergus County below 4500ft-Judith Basin County and Judith Gap-Snowy and Judith Mountains-Western and Central Chouteau County.