FXUS65 KTFX 090405 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 905 PM MST Wed Jan 8 2025 .KEY MESSAGES... - Band of light snow continues to move southward through the CWA this evening. - Quiet weather expected for Thu and Fri. - The next storm arrives Friday night, with the potential for heavy mountain snow over Kings Hill, Bears Paw and Big Snowy mountain ranges && .UPDATE... The primary shortwave that brought strong winds and areas of snow to the region earlier today has moved southeast of the forecast area, however a moist north-northwest flow aloft with trailing weaker shortwave energy continues to stream across the region in its wake. Snow showers with potential for measurable accumulation are primarily focused across areas in the vicinity of the mountain ranges of central and southwest MT overnight. Satellite imagery shows the final disturbance in this flow currently moving through far southern AB and this feature may produce some light snow showers with little or no accumulation as it tracks south through western portions of north-central MT overnight and SW MT Thursday morning. Winter weather advisories continue through the overnight period for the central and SW MT mountain ranges where some additional snow accumulation is expected. Winds will continue to diminish overnight along with any lingering drifting/blowing snow impacts. Once concern for area roads that will persist into Thursday morning is the potential for icing of road surfaces that were wet/slushy earlier today as temperatures fall below freezing overnight. Hoenisch && .DISCUSSION... /Issued 504 PM MST Wed Jan 8 2025/ - Meteorological Overview: With the surface low moving off into northern Canada, the strong winds have decreased over North Central MT. However, an upper level disturbance continues to move southward through North Central MT this afternoon, producing areas of rain/snow. This band of snow will move into Southwest MT by this evening, and then end by Thursday morning. A weak upper level ridge develops over the CWA for Thu and Fri, resulting in mostly quiet weather conditions. On Friday night, a stronger upper level trof will approach MT resulting in snow developing by Friday night over Central MT. The snow could be heavy at times by Saturday over the mountains around Kings Hill, Bears Paw and Big Snowy mountain ranges. Most of the snow ends Sunday, with just a few snow showers left on Monday. A stronger upper level ridge builds over the CWA by Tuesday, resulting in mostly dry conditions for Tue/Wed. - Forecast Confidence & Scenarios: The high wind warning was cancelled for the Cut Bank area, as the strong winds have diminished. The winter weather advisory was cancelled for the western and northern portions of the CWA, as the blowing snow has ended and snow has pushed south of the Hi-line. A band of rain/snow will continue to move southward through the central and southern portions of the CWA this evening/overnight. Thus the winter weather advisory will expire at different times this evening as the snow exits the area. For Friday night/Saturday...there is an 50 percent chance snow accumulations could exceed 6 inches in the Bears Paw and Big Snowy mountains and an 80 percent chance of 10 inches or more in the Kings Hill area. With the potential that snow amounts could actually be a bit higher in these areas, these 3 mountain locations have been placed in a winter storm watch. There is a chance of accumulating snow going into Sunday and addition winter statements might be needed. Additionally, some lower elevation locations around these mountain ranges might need a winter weather advisory over the weekend as well. Brusda && .AVIATION... 09/00Z TAF Period Area of snow continues south through remaining portions of central and southwest MT with improving conditions at KLWT but a period of lower vis/cigs in likely at KHLN and KBZN this evening. Areas of low clouds, mountain obscuration and scattered snow showers are likely to persist overnight in moist northerly flow, especially near the central and southwest MT mountain ranges. Also cannot rule out some patchy fog development across SW MT valley locations later tonight including KHLN and KBZN. Gusty west to northwest surface winds will continue to diminish overnight as well with further improvement to clouds/ceilings expected from north to south across the area Thursday morning. Hoenisch Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PRELIMINARY POINT TEMPS/POPS... GTF 22 33 18 40 / 30 0 0 10 CTB 20 30 18 38 / 30 0 0 10 HLN 20 33 17 38 / 60 0 0 10 BZN 19 32 10 37 / 50 20 0 10 WYS 2 27 -1 22 / 40 0 0 10 DLN 15 30 12 34 / 40 10 0 0 HVR 21 30 12 39 / 10 0 0 10 LWT 20 32 15 44 / 40 10 0 10 && .TFX WATCHES/WARNINGS/ADVISORIES... Winter Storm Watch from Friday afternoon through Saturday afternoon for Bears Paw Mountains and Southern Blaine-Little Belt and Highwood Mountains-Snowy and Judith Mountains. Winter Weather Advisory until 5 AM MST Thursday for Big Belt, Bridger and Castle Mountains-Gallatin and Madison County Mountains and Centennial Mountains-Little Belt and Highwood Mountains-Snowy and Judith Mountains. && $$ http://www.weather.gov/greatfalls