FXUS65 KTFX 111810 AAA AFDTFX Area Forecast Discussion...UPDATED National Weather Service Great Falls MT 1110 AM MST Mon Dec 11 2023 Aviation Section Updated .SYNOPSIS... A weak cold front moves south across the region today with areas of snow affecting primarily north-central and central Montana this morning. Drier conditions are expected Tuesday and Wednesday, but breezy to windy southwesterly winds return. && .UPDATE... As of 8 AM, radar imagery and surface observations show light rain and snow across Central Montana moving southward into Southwest Montana this morning. Rain/Snow should arrive in locations from Helena to White Sulfur Springs within the next hour as the cold front moves southward across our CWA this morning. Please use caution while driving this morning as roadways could be icy and/or slippery in locations that see precipitation and below freezing surface temperatures as well as periods of reduced visibility below 6 miles with falling snow. As the cold front continues to move southward, precipitation should be ending by late this morning and this afternoon from north to south across Central and Southwest Montana. Fog has been periodically observed on webcams and night fog satellite across Bozeman and Belgrade this morning. The Winter Weather Advisory for the Little Belt and Highwood Mountains continues through 1 PM and was expanded to include the Southern Rocky Mountain Front as snowfall can accumulate to between 1 and 3 inches and winter weather impacts continues through the morning hours such as slippery roadways and reduced visibility with falling snow. Webb && .AVIATION... 1100 AM MST Mon Dec 11 2023 (11/18Z TAF Period) From KGTF to KLWT, we have a band of light to moderate snowfall that will continue through 20z and 21z bringing LIFR to IFR conditions. Mountain obstruction continues for Central Montana mountains until this evening. For KHLN, a mix of rain and snow can be observed through at least 21z. VFR conditions for KHVR and KCTB continue through the TAF period. Visibility will improve to VFR conditions later this afternoon for Central Montana airfields. For KBZN and KEKS, there is potential in the morning hours for low level clouds and fog to develop. The chances for fog were too low to include in the TAFs at this time, but the potential for low clouds tomorrow morning is high to be included in the TAF. Webb Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PREV DISCUSSION... /ISSUED 354 AM MST Mon Dec 11 2023/ A weak cold front was moving south across north-central MT early this morning, roughly from Choteau to Chester at 3am where winds have shifted to the NW with some slight cooling. Radar across north- central MT and upstream across southern AB shows mainly light returns but increasing coverage behind the front early this morning. Hi-resolution models seem to have a good handle on the frontal position and upstream precipitation and expect the development of areas of light snow or flurries across much of north-central MT by 5am with a more concentrated area of light snow likely to develop from the Rocky Mtn Front southeast across the northern portions of the Big Belt and Little Belt mountains and roughly as far north as areas from Choteau to Great Falls and Stanford. The frontal boundary and areas of light snow will continue south through this afternoon with coverage decreasing as the front weakens while moving through SW MT. Snow amounts have changed little from previous forecasts with north-central and central MT mountains ranges likely to see around 1-3" of snow while adjacent valleys and plains can expect Trace to 1" amounts while little or no snow accumulation is expected in the valleys of SW MT. Precipitation ends form N to S this afternoon with some low clouds lingering across central MT into early this evening before all areas see skies clear tonight. A dry and relatively mild stretch of weather begins Tuesday as upper level ridging becomes established across the western US and is likely to persist through the upcoming weekend. There is some potential for windy periods across north-central MT as shortwave disturbances move over the ridge across western Canada around the middle of this week and again this weekend. Temperatures look to fluctuate 10-15 degrees above seasonal averages for mid-December. In fact, today's seasonably cool conditions may be the coldest of the next two weeks with global model ensembles strongly favoring an extended period of mild zonal from from the Pacific across the continent through late December. Hoenisch && .PRELIMINARY POINT TEMPS/POPS... GTF 37 23 41 27 / 90 0 0 0 CTB 33 17 38 22 / 60 0 0 0 HLN 39 23 41 19 / 80 0 0 0 BZN 39 19 37 12 / 40 20 0 0 WYS 31 8 33 -1 / 20 10 0 0 DLN 37 20 35 14 / 10 10 0 0 HVR 36 15 37 20 / 50 0 0 0 LWT 36 20 41 22 / 70 0 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 11 AM MST this morning for East Glacier Park Region. Winter Weather Advisory until 1 PM MST this afternoon for Little Belt and Highwood Mountains-Southern Rocky Mountain Front. && $$ http://www.weather.gov/greatfalls