801 FXUS65 KTFX 121005 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 305 AM MST Wed Feb 12 2020 .SYNOPSIS... A cold airmass spreading south into the area this morning with snow and gusty north winds gradually decreasing late this morning into this afternoon. Drier conditions are expected tonight through Thursday with afternoon temperatures returning to seasonal averages for most areas by Thursday afternoon. Gusty southwest winds may develop over portions of north-central Montana late Thursday and Thursday night. && .DISCUSSION... Today...A secondary push of colder air was surging south across N-central MT early this morning in association with a strong area of surface high pressure moving south from AB/SK. This should be the final but strongest surge of northerly winds southward across the forecast are with gusts to 30kts across much of north-central MT for several hrs early this morning, spreading south into SW MT where gusts to 25 kts will funnel southwards through the valleys after 6 AM. Snow remains most persistent over the central MT Mtns where several additional inches of snowfall are expected before precipitation diminishes later this morning with enhanced areas of snowfall this morning also likely near the Elkhorn, Tobacco Root and Gallatin Ranges of SW MT. Snow showers or flurries are still likely through this morning over areas north of Great Falls, but with little additional accumulation expected there will cancel the winter weather advisory. Still expect very poor conditions from areas just east of Great Falls to Lewistown and south to the Little Belts and Big Snowy mountain ranges, where snowfall will be most persistent and gusty winds will continue to create significant blowing and drifting through this morning before winds and snow decrease late this morning through the afternoon. Temperatures will continue to fall through late this morning as the cold airmass slides south into eastern MT and temperatures will likely remain steady in 20s for many locations this afternoon and only in the teens for Blaine and Hill counties. Tonight through Thursday night...Upper level ridging building into the Pacific NW will bring further drying tonight while the cold surface high pressure area shifts SE to the Dakotas while low pressure develops along the east slopes of the Rockies. The lee-side low pressure trough continues to deepen though Thursday night as the upper level ridge shifts east across the Northern Rockies and MT. This will bring another quick rebound to near or even slightly above average temperatures by Thursday afternoon along with increasing winds. Increasing winds will likely create some blowing and drifting snow issues where a snowpack is in place and there looks to be at least marginal potential for wind gusts in excess of 50kts Thursday night for areas adjacent to the Rocky Mtn Front and possibly across the Judith Basin area as well. Hoenisch Friday through next Wednesday...Period begins with a fairly potent, but fast moving shortwave trough sliding east across the Northern Rockies during the day on Friday, which will bring primarily light snowfall to the mountains of the CWA, and breezy southwest-to-west winds to the plains/valleys. A Pacific front will also accompany the passage of this aforementioned shortwave, generally crossing CWA between 12-18z Friday morning. Given weak elevated instability and steepening lapse rates (due to strong cold air advection aloft), expect precipitation on Friday to take on a convective aspect, with even the possibility of some snow squalls along the eastward advancing Pacific front. Overall, snowfall accumulations in the mountains from Thursday night through Friday afternoon of 1-3" are generally expected, with possibly up to 6" along the Continental Divide in Glacier County. Accumulations at lower elevations will generally be less than 1", but sudden reductions in visibility in snow squalls will be possible. Following the shortwave on Friday, transient ridging (zonal flow) builds (develops) across the region through the evening hours on Saturday, which will allow temperatures to once again warm above climatological norms at most locations (on Saturday). Breezy condtions will once again be experienced Saturday/Saturday night, especially along the Rocky Mountain Front, northern foothills of the Central Montana mountains, and in the north-to-south orientated valleys of Southwest Montana. Another shortwave trough will then cross the region Saturday night through Monday morning, once again bringing mountain snow to the region and even some accumulations to lower elevations. Compared to last night, snowfall amounts over the plains and valleys have increased, with most lower elevations possibly seeing 1-3". Snowfall accumulations in the mountains have also increased, with 6-12" now possible. Ridging then builds back in over the Northern Rockies by Monday afternoon and lingers into the middle of the work week. - Moldan && .AVIATION... Updated 1015 PM MST Mon Feb 11 2020 (12/06Z TAF Period) MVFR/IFR conditons are primarily expected across the region through 12-18z Wednesday; however, periods of LIFR conditions are possible with and immediately after a southward surging cold front from between 06-12z. Conditions are expected to improve to VFR through the afternoon hours on Wednesday as transient ridging slides and builds towards the Northern Rockies, but some linger mountain snow showers will likely persist given the northwest flow aloft. Mountain obscuration will continue through the entire TAF period. Finally, low level wind shear will remain possible over Southwest Montana, specifically the KWYS terminal, into the early morning hours on Wednesday as surface winds relax but winds aloft of 30-40kts remain over the region. -Moldan && .PRELIMINARY POINT TEMPS/POPS... GTF 27 13 43 27 / 70 0 0 0 CTB 24 10 39 24 / 30 0 0 10 HLN 31 16 42 24 / 30 10 0 0 BZN 30 11 38 20 / 50 10 0 10 WYS 26 4 26 11 / 30 10 10 30 DLN 31 13 34 21 / 40 10 0 10 HVR 19 4 35 26 / 10 0 0 0 LWT 21 7 35 25 / 70 20 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 11 AM MST this morning Cascade... Fergus...Judith Basin...Meagher. && $$ http://www.weather.gov/greatfalls