FXUS65 KTFX 020313 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 913 PM MDT Tue Oct 1 2024 .SYNOPSIS... Slightly cooler temperatures and lighter winds are expected for Wednesday and Thursday. Another Pacific weather system and attendant cold front will bring a windy warm day on Friday followed by a gusty cold frontal passage Friday night into Saturday. High pressure builds in for the the second half of the weekend into early next week for dry conditions and more well above normal temperatures. && .UPDATE... The evening update has been published. Elevated westerly flow aloft will maintain gusty winds and mild temperatures overnight tonight, mostly for Rocky Mountain Front and plains locations. A cold front drops south from Canada and moves through Central/North-central MT late tonight into Wednesday and brings a northerly wind shift, scattered cloudiness, and a slight cool down. Mostly dry conditions are expected, but a few lighter end showers can be expected, mostly along the higher terrain along the Rocky Mountain Front. - RCG && .AVIATION... 02/00Z TAF Period Gusty westerly winds and associated mountain wave turbulence and instances of low level wind shear will continue into the overnight hours for locations along the Rocky Mountain Front and the plains; however, surface wind speeds will generally diminish to the 10 to 20 kt range with gusts up 35 kts times. A cold front trekking southward out of the Canadian prairies passes through Central/North-central MT between 02/10 and 02/18Z and brings more of a northerly wind shift, a period of lower VFR clouds and perhaps some mountain obscuration. Otherwise, VFR conditions will prevail for the duration of the TAF period. - RCG Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .FIRE WEATHER... After a couple of days of slightly cooler temperatures and lighter winds, another Pacific weather system and attendant cold front will bring a windy warm day with elevated fire weather conditions on Friday followed by a strong cold frontal passage with potential for wind gusts over 50 mph Friday night into early Saturday. && .PREV DISCUSSION... /ISSUED 202 PM MDT Tue Oct 1 2024/ Key Points: -Breezy with elevated fire weather conditions today -Windy on Friday as a dry cold front pushes through -Dry weather continues next week Short term (through Thursday)... In the short term, expect a fairly quiet, if breezy, weather pattern to continue as our upper level winds remain zonal (westerly) thanks to a persistent upper level jet over the area. Thanks to this pattern, expect temperatures Wednesday and Thursday to remain within 5 degrees of average for highs, with overnight lows also near average as well aside from well above average lows overnight tonight. Extended (Friday through next Tuesday)... Friday will look to be the busiest weather day of the next week as a sharp upper level shortwave trough slides across Southern Canada and through the Northwestern US. While uncertainty certainly remains, there has been a notable trend in the ensemble forecasts to begin to increase confidence in a very windy day across the plains and ridges, with NBM probabilities for 60 mph winds increasing significantly over the past 12-24 hours. While I will not yet list exact probabilities as this trend has been unusually sudden, we are starting to see a greater than 50% chance for 55 mph wind gusts or higher in some of the usual windy spots. Dynamically, this system does seem to have the capability to produce such winds thanks to a combination of a deep layer of strong winds in the mid levels, deep mixing ahead of the front and strong cold air advection behind the front along with a few mountain waves, I think it would be prudent to hold off on any High Wind Watches for just a bit longer as there are still a few ensemble tools that are less enthused about the winds, notably the EFI that is run by NCEP. For now, we will begin to gradually increase our messaging about Friday’s potential for winds, with future shifts re- evaluating the situation for any potential High Wind Watches. Winds will gradually diminish overnight Friday night and through Saturday morning, with winds calming by Saturday evening as high pressure builds in across Eastern Montana. Aside from occasional breezes, expect a warm, dry, and fairly tranquil weather pattern to develop for next week as an anomalously strong upper level ridge begins to develop across the Western United States. Ludwig && .PRELIMINARY POINT TEMPS/POPS... GTF 51 65 34 62 / 0 0 0 0 CTB 40 57 30 60 / 0 10 10 0 HLN 49 67 35 63 / 0 0 0 0 BZN 40 70 30 63 / 0 0 0 0 WYS 24 65 22 62 / 0 0 0 0 DLN 40 70 29 64 / 0 0 0 0 HVR 46 61 35 63 / 0 0 10 0 LWT 50 62 32 59 / 0 0 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls