FXUS65 KTFX 021452 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 852 AM MDT Fri May 2 2025 Aviation and Forecast Section Updated. .KEY MESSAGES... - Above average temperatures expected today and Saturday. - Cool and wet conditions are expected Sunday and Monday, with mainly mountain snow and lower elevation rain. - Near to above average temperatures return for mid to late next week. && .UPDATE... Current forecast is on track. No updates planned for this morning. Some high clouds continue to move southward, affecting areas mainly east of a line from Butte to Havre. These clouds should diminish by this evening, as drier air moves in from the north. Otherwise, expect a sunny and warm day today. Afternoon temperatures will continue to warm for Saturday...and generally average about 5 degrees warmer than today, along with plenty of sunshine. The next chance for widespread rain arrives Sunday afternoon and evening, with most lower elevation locations receiving rainfall of about 0.05 inches to about 0.25 inches, and around a half inch possible in the mountains. Brusda && .DISCUSSION... /Issued 456 AM MDT Fri May 2 2025/ - Meteorological Overview: Upper level ridging over the Western CONUS will remain overhead today and Saturday, which will result in warm and dry conditions to close out the week. However, this ridge will not hang around very long, as an upper level trough will push into the Pacific Northwest on Sunday, bringing cooler temperatures, widespread precipitation, and even some mountain snowfall to the area Sunday and Monday. While Tuesday will see precipitation clear out, a lingering upper level low over the Four Corners may help spur the development of a few additional rain showers as late as Tuesday before weak upper level ridging begins to build back into the area for the end of the work week. - Forecast Confidence & Scenarios: While the bookends of this forecast period both have relatively high confidence in the overall weather pattern (warm and dry under upper level ridges), the main area of uncertainty will be with the cooler and wetter period early next week, in particular precipitation type and amounts. For precipitation type, most models are in good agreement that precipitation at all but the highest terrain will be mostly rain, though a few of the mountain passes are liable to get a slushy coating of snow over the course of the event. However, the GFS and the NAM operational models both want to bring snow levels down closer to 3000 feet, which could bring snow to some valley and plains locations should this occur. As of now, however, I suspect that these models are running a bit cool and this solution is less likely, and even if some snowflakes do mix in impacts are unlikely to be widespread or significant given that ground temperatures have been warming up thanks to recent warm weather. As far as amounts go, there has been some hinting towards localized amounts over an inch along the Southern Rocky Mountain Front, though current probabilistic data suggests around a 30% - 40% chance at most over a 3 day period. While this is likely to cause some rises on rivers and streams, given the drawn out nature of this event flooding is not expected at this time. Ludwig && .AVIATION... 02/18Z TAF Period High clouds continue to affect areas mainly east of a line from Butte to Havre this morning. The clouds will generally thin out by 02z on Sat. Otherwise, VFR and quiet weather conditions are expected. Brusda Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PRELIMINARY POINT TEMPS/POPS... GTF 78 44 81 48 / 0 0 0 10 CTB 76 41 80 47 / 0 0 0 20 HLN 79 46 83 49 / 0 0 0 10 BZN 73 39 78 42 / 0 0 0 0 WYS 65 26 70 30 / 0 0 0 0 DLN 73 40 76 42 / 0 0 0 0 HVR 78 42 84 46 / 0 0 0 0 LWT 72 44 77 48 / 0 0 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls