Area Forecast Discussion
Issued by NWS Great Falls, MT
Issued by NWS Great Falls, MT
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703 FXUS65 KTFX 092202 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 302 PM MST Tue Dec 9 2025 .KEY MESSAGES... - Gusty winds continue through the afternoon today. - Another round of strong winds Wednesday for mainly the Rocky Mountain Front, with gusty winds still across the plains. - Another round of rain and snow Wednesday, with better chances of accumulating snow at lower elevations Thursday through Saturday morning. - Temperatures rapidly drop below freezing behind an arctic front Thursday. && .DISCUSSION... - Meteorological Overview: A low pressure system will continue to bring lower elevation rain/snow and mountain snow this afternoon. The mid level jet will continue to move out of the region this afternoon, which will help decrease gusty to strong winds this evening. Another upper-level disturbance arrives Wednesday and a warm front lifts north Wednesday morning. This will bring more of a wintry mix at lower elevations, transitioning to snow to rain. There is a shallow enough warm nose along the warm front that there is a low chance for a window of an hour of light freezing rain during the transition along the Hi-line. A strong mid level jet moves in Wednesday along the Rocky Mountain Front, which will bring strong winds to the area. This mid level jet extending out farther east across the North-Central MT plains will bring gusty winds throughout the day. Thursday through early Saturday morning, better chances for accumulating snow at lower elevations arrives along an an arctic front passing through the region Thursday. Temperatures quickly dropping behind the front Thursday will likely cause a flash freeze on roads. The front is expected to stall out somewhere across North- Central MT Thursday night through Friday. Another wave of Pacific moisture moves in Friday, which will keep periods of moderate to heavier snow around North-Central MT through Saturday. -Wilson Over the weekend and into early next week, the forecast models want the cold air to retreat back into Canada very quickly. Sometimes this is too quick, but if southerly winds are strong enough, it is possible for the cold air to move back north rather quickly. -Brusda - Forecast Confidence & Scenarios: Winds Wednesday: Hi-res guidance showing a mid level jet approaching 85kts at times along the Rocky Mountain Front during peak vertical mixing (late morning to early afternoon). This brings good confidence for strong winds along the Rocky Mountain Front to upgrade to a High Wind Warning. With the mid-level jet still strong extending further east, a few other areas across the North-Central MT plains will try to produce strong winds as well. However, with a 50% or less chance of 58mph wind gusts, they were left out of the warning at this time. Snow Thursday/Friday: Confidence is increasing for impactful snow across the North- Central plains. There are still some timing differences in when and where the heavier snowfall occurs. Guidance now has flopped to Friday having the moderate to heavier snow band set up across the North- Central MT plains with additional Pacific moisture advecting in. However, strong cold air advection long the arctic front Thursday will crash road temperatures behind the front. Frontogenetic banding along the front will bring a moderate band of snow. With that, I decided to start the Winter Storm Watch based on when the flash freeze will happen for the start time Thursday. Timing will be ironed out better as models start to come into better agreement in the coming days. - Wilson && .AVIATION... 09/18Z TAF Period MVFR/low-VFR conditions will largely prevail through the 0918/1018 TAF period, but some periods of IFR can`t be ruled out beyond 09z Wednesday beneath heavier burst of precipitation. The probability of these IFR conditions occurring is currently around a 30% chance at the KCTB, KLWT, and KBZN terminals. Otherwise the main concern through the TAF period will be instances of low level wind shear and mountain wave activity as strong mid-level flow continues over Montana. Mountains will be obscured for most of the next 24 hours. - Moldan && .PRELIMINARY POINT TEMPS/POPS... GTF 31 55 44 53 / 40 50 40 80 CTB 25 47 23 39 / 60 50 50 70 HLN 32 53 45 52 / 60 70 30 60 BZN 30 53 41 53 / 60 40 10 30 WYS 24 40 29 39 / 80 80 20 30 DLN 32 53 39 53 / 60 10 0 10 HVR 20 44 25 35 / 20 70 70 80 LWT 24 48 37 49 / 30 90 40 80 && .TFX WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from midnight tonight to 11 AM MST Wednesday for East Glacier Park Region-Southern Rocky Mountain Front. High Wind Warning from 8 AM to 8 PM MST Wednesday for Eastern Glacier, Western Toole, and Central Pondera-Northern High Plains- Southern High Plains. Winter Storm Watch from Thursday morning through late Friday night for Bears Paw Mountains and Southern Blaine-Eastern Glacier, Western Toole, and Central Pondera-Eastern Toole and Liberty-Hill County-Northern Blaine County. Winter Storm Watch from Thursday afternoon through late Friday night for Cascade County below 5000ft-East Glacier Park Region- Eastern Pondera and Eastern Teton-Fergus County below 4500ft- Judith Basin County and Judith Gap-Little Belt and Highwood Mountains-Northern High Plains-Snowy and Judith Mountains- Southern High Plains-Southern Rocky Mountain Front-Western and Central Chouteau County. && $$ http://www.weather.gov/greatfalls