Area Forecast Discussion
Issued by NWS Great Falls, MT
Issued by NWS Great Falls, MT
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569 FXUS65 KTFX 252132 CCA AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 332 PM MDT Sat May 25 2024 .SYNOPSIS... Shower and isolated thunderstorm activity slowly diminishes from west to east tonight. Breezy to windy conditions are expected on Sunday with shower chances mostly confined to the Hi-Line. Much Drier and warmer weather is expected for Memorial Day and most of Tuesday before shower and thunderstorm chances return later Tuesday into Wednesday. && .DISCUSSION... Tonight through Monday... Scattered showers and thunderstorms will persist through the rest of the afternoon across most of central and southwestern Montana. Overall, the threat for severe weather is minimal, however, a gust or two up to 50 mph and some pea-sized hail is possible. Showers will quickly taper off after sunset for north-central and central Montana. Some lingering showers will remain for southwestern Montana through around 3 AM before tapering off. For tonight, model soundings are still split on fog developing around Bozeman. There is just enough confidence and potential for fog developing after the last of the showers move through early tomorrow morning that a 20% chance for patchy fog was added to the Gallatin Valley and portions of far southwestern Montana. Widespread dense fog is not expected but it would not be surprising for a couple isolated places to reach a quarter of a mile in visibility at times. Otherwise, as the shortwave continues east there will be another chance for isolated showers and thunderstorms along the hi-line Sunday afternoon. Memorial Day will be warmer and drier across the region with generally light winds and partly cloudy skies except along the northern Rocky Mountain front. -thor Tuesday through Saturday... An upper level ridge will be over the area on Tuesday morning, which will quickly break down by Tuesday afternoon, as an upper level trof approaches from the west. Tuesday will likely be the warmest day over the next week, but I did lower NBM guidance a few degrees for Tuesday afternoon, as it might be too warm. Otherwise, the main concern Tuesday is for the potential for severe storms Tuesday afternoon/evening. With the flow aloft becoming southwest, it will be unstable by late afternoon. However, it is not that unstable, thus the potential for widespread severe storms looks low at this time. On Wednesday, the main cold front moves though. Temperatures will start to cool a bit, as well as the potential for heavy rainfall over Central MT. Right now there is about a 30 percent chance for locations between Great Falls and Lewistown to receive 0.50 inches of rainfall. This would be convective rainfall, thus portions of Central MT are in a marginal risk for excessive rainfall during this period. It does remain unsettled for Thus/Fri with scattered showers continuing and afternoon temperatures just a few degrees below normal. Brusda && .AVIATION... 25/18Z TAF Period Mid-level clouds and showers will continue to increase and spread east across remaining portions of north-central MT this afternoon ahead of upper level weather disturbance crossing the Northern Rockies. Scattered thunderstorms develop and track east across the area this afternoon with 50-60% probabilities for thunderstorms at/near KBZN, KEKS and KWYS and 30-50% probabilities for KGTF, KHVR and KLWT. Gusty winds will accompany most showers and thunderstorms this afternoon wish some small hail possible in isolated/more intense cells. Otherwise some brief MVFR and mountain obscuration is expected in the vicinity of showers/thunderstorms this afternoon and evening with showers and clouds decreasing as the system exits overnight. Some patchy fog is possible in KBZN area late tonight as clouds decrease following the showers. Westerly surface winds increase this afternoon and evening with the passage of the weather disturbance with breezy to locally windy conditions likely to develop at most terminals on Sunday. Hoenisch Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PRELIMINARY POINT TEMPS/POPS... GTF 41 63 40 73 / 40 10 0 0 CTB 40 60 39 70 / 10 10 0 0 HLN 42 64 43 76 / 20 10 0 0 BZN 36 62 36 71 / 70 10 0 0 WYS 33 55 30 64 / 80 20 0 0 DLN 35 63 36 71 / 50 0 0 0 HVR 44 65 43 73 / 40 30 10 0 LWT 38 58 37 67 / 80 10 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls