FXUS65 KTFX 101755 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 1055 AM MST Mon Feb 10 2025 Aviation Section Updated. .KEY MESSAGES... - Light snow will linger in North-central, Central, and Southwestern Montana this morning. - Arctic air settles in across much of North-central, Central, and Southwestern Montana today and continues for much of this week outside of Thursday with the coldest temperatures of this winter so far expected this evening through Tuesday morning. - Late this week there is the potential for another round of widespread snow. && .UPDATE... /Issued 911 AM MST Mon Feb 10 2025/ Two main changes with this update. The first being precipitation chances across central and southwest Montana. Observations are showing much more widespread snow than what was previously forecasted so precipitation chances were brought up to better reflect that as well as short-term hi-res model guidance. In general, the snow should taper off for most locations after 12 PM with some lingering snow showers in the mountains and in portions of southwest Montana. But otherwise, most of the snow is expected to end by the afternoon. Another main change was the low temperatures Tuesday night into Wednesday morning. The updated NBM came in 2 to 3 degrees colder across much of the CWA and the updated lows now reflect that change. At this point in time, no additional products will be issued for Tuesday into Wednesday, however, depending on how future model guidance plays out, additional cold weather advisories cannot be ruled out. Otherwise, no major changes to the going forecast. -thor && .DISCUSSION... /Issued 911 AM MST Mon Feb 10 2025/ - Meteorological Overview: There will be light snow across North-central, Central, and Southwestern Montana this morning. An arctic front associated with an upper-level trough is sliding south from Canada this morning which will bring arctic air back to North-central, Central and Southwestern Montana today through Tuesday morning. On Tuesday an upper-level ridge begins to move back over North- central, Central, and Southwestern Montana. It will remain over the area through Thursday afternoon. This will gradually warm temperatures back up across North-central, Central and Southwestern Montana through Thursday except for in cold prone valleys. Tuesday night through early Wednesday morning a quick moving shortwave will bring light snow to a portion of North-central and Central Montana. Thursday afternoon an upper-level trough combined with an arctic front will bring another blast of arctic air from Canada to North- central Montana on Friday and Saturday which will cool temperatures back down. Thursday night through Friday due to the warm air in Southwestern Montana and warm air aloft combined with Pacific moisture there will be an overrunning snow event in North-central and Central Montana and snow in Southwestern Montana. - Forecast Confidence & Scenarios: For snow Tuesday night into early Wednesday morning there is a 10 - 40% chance for greater than a trace of snow between the Southern Rocky Mountain Front and the Highwoods. For snow Thursday night through Friday across most of the lower-elevations of North-central, Central, and Southwestern Montana there is a 30 - 50% chance for an inch of snow or greater. Across the mountains of North-central, Central, and Southwestern Montana there is a 40 - 60% chance for two inches of snow or greater from Thursday night through Friday. For cold high temperatures on Monday there is greater than a 90% chance for high temperatures below 0 across the plains of North- central and Central Montana. On Tuesday and Wednesday there is 50 - 70% chance for highs below zero in the Gallatin Valley over to the Canyon Ferry area. For cold high temperatures on Friday and Saturday there is a 50 - 80% chance for highs below 0 across the plains of North-central Montana. On Tuesday morning there is a 50 - 75% chance for low temperatures of 20 below or colder across the plains of North-central Montana. From the Helena Valley to the Gallatin Valley there is greater than a 80% chance for low temperatures of 20 below or colder Tuesday morning. Along the Hi-Line and in the Helena Valley there is around a 60% chance for lows of 25 below or colder Tuesday morning. Along the Hi-Line there is a 10 - 30% chance for lows of 30 below or colder on Tuesday morning. In the Gallatin Valley Tuesday morning there is a 60 - 75% chance for a low of 30 below or colder. As a result for all of North-central, Central, and some of Southwestern Montana the Extreme Cold Watch was upgraded to a warning Monday evening through Tuesday morning. A Cold Weather Advisory was issued for the rest of Southwestern Montana from Monday evening through Tuesday morning. Also a Extreme Cold Warning was issued from this morning through this evening along the Hi-Line. On Wednesday morning there is around a 30 - 50% chance for lows of 20 below or colder along the Hi-Line and in the Helena Valley. On Wednesday and Thursday morning there is greater than a 80% chance for lows of 20 below or colder in the Gallatin Valley. -IG && .AVIATION... 10/18Z TAF Period As high pressure builds in across North Central and Southwestern Montana, expect skies to gradually clear out this afternoon and overnight tonight as temperatures continue to drop. Aside from a brief snow shower at KBZN early this afternoon, expect mostly VFR conditions across the area with temperatures at the surface dipping into the teens and 20s below zero overnight. Ludwig Equipment note: The observation at KEKS stopped transmitting. Will update the TAF to remove AMD NOT SKED when the situation is resolved. Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PRELIMINARY POINT TEMPS/POPS... GTF -2 -25 7 -15 / 50 0 0 10 CTB -6 -26 10 -18 / 30 0 0 0 HLN 3 -21 3 -15 / 40 0 0 0 BZN 7 -31 -1 -21 / 70 0 0 0 WYS 16 -29 11 -27 / 30 10 0 0 DLN 7 -19 3 -17 / 40 0 0 0 HVR -6 -24 4 -18 / 10 0 0 0 LWT -4 -21 6 -15 / 50 0 0 10 && .TFX WATCHES/WARNINGS/ADVISORIES... Extreme Cold Warning from 5 PM this afternoon to 11 AM MST Tuesday for Beaverhead and Western Madison below 6000ft-Big Belt, Bridger and Castle Mountains-Canyon Ferry Area-Cascade County below 5000ft-Eastern Pondera and Eastern Teton-Elkhorn and Boulder Mountains-Fergus County below 4500ft-Gallatin Valley- Gates of the Mountains-Helena Valley-Judith Basin County and Judith Gap-Little Belt and Highwood Mountains-Meagher County Valleys-Snowy and Judith Mountains-Southern High Plains-Southern Rocky Mountain Front-Upper Blackfoot and MacDonald Pass-Western and Central Chouteau County. Cold Weather Advisory from 5 PM this afternoon to 11 AM MST Tuesday for Gallatin and Madison County Mountains and Centennial Mountains-Madison River Valley-Missouri Headwaters-Northwest Beaverhead County-Ruby Mountains and Southern Beaverhead Mountains. Extreme Cold Warning until 5 PM MST this afternoon for Bears Paw Mountains and Southern Blaine-East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera-Eastern Toole and Liberty-Hill County-Northern Blaine County-Northern High Plains. Extreme Cold Warning from 6 PM this evening to 11 AM MST Tuesday for Bears Paw Mountains and Southern Blaine-East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera- Eastern Toole and Liberty-Hill County-Northern Blaine County- Northern High Plains. && $$ http://www.weather.gov/greatfalls