Area Forecast Discussion
Issued by NWS Great Falls, MT
Issued by NWS Great Falls, MT
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505 FXUS65 KTFX 181016 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 416 AM MDT Sat May 18 2024 .SYNOPSIS... Today is forecast to be dry, mild and on the cool side, with periods of breezy to gusty winds. Daily isolated afternoon and evening thunderstorms are forecast through the early part of next week. For the next several days, temperatures remain cooler than normal, with periods of gusty winds and an active weather pattern that favors periods of rain and high elevation snow. && .DISCUSSION... Note: The forecast area for the National Weather Service Great Falls Weather Forecast Office includes north central, central and southwest Montana. Today...A broad upper level trof stretches across the Canadian Provinces of British Columbia, Alberta and Saskatchewan. Within, closed upper level areas of lower heights rotate through this trof. To our south, a weak upper level ridge resides over the Four Corners region. Off of the southern California/Baja Peninsula west coast resides a closed upper area of lower heights, and just upstream of that trof lies a strong upper level ridge. As a result, a westerly cross-barrier flow develops across The Rocky Mountain Front, favoring widespread non-warning criteria gusty winds. A few rumbles of thunder may be heard along The Northern Rocky Mountain Front, this afternoon and evening. Aside from gusty winds and maybe a few thunderstorms, today is forecast to be dry, mild and on the cool side. Sunday through next Saturday...Sunday, as one of the Canadian minor shortwave trofs rotates through the main trof, removing mass from the broad upper level trof, the wave begins to feel the upper level closed area of lower heights off of the southern US/Baja Peninsula west coast, causing the upper level trof to deepen. Afternoon and evening thunderstorm activity is forecast through Monday. Numerical Weather Prediction models are in agreement that this deep trof remains the dominant upper level feature over The Treasure State through Thursday. The best chance of receiving an inch or more of precipitation in a 24-hr period, is forecast for Thursday, when north central and central Montana has a 20% or less chance of receiving one or more inches of moisture in 24 hours. Beyond Thursday, numerical model solutions become divergent, with some favoring the development of an upper level ridge over our area, while others continue to include upper level trofing as the dominant feature. The National Blend of Models is favoring and active weather pattern, at least, through next Saturday. The resultant weather, throughout this period, includes cooler than normal temperatures, periods of gusty winds, as well as, periods of rain and high elevation snow. - Fogleman && .AVIATION... 18/06Z TAF Period VFR conditions prevail this TAF period. A few showers remain across eastern portions of the plains but will continue to diminish or shift eastward and away from the region. Gusty winds diminish overnight but become breezy again Saturday. Mountain wave turbulence will be possible through the day Saturday. -AM Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PRELIMINARY POINT TEMPS/POPS... GTF 62 39 56 38 / 10 20 80 50 CTB 58 33 55 35 / 20 20 80 40 HLN 66 42 58 39 / 0 30 70 30 BZN 66 35 55 33 / 10 20 80 20 WYS 58 35 52 27 / 0 30 50 20 DLN 65 34 54 32 / 0 10 40 10 HVR 63 38 60 39 / 10 10 70 30 LWT 59 37 53 34 / 0 20 80 30 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls