FXUS65 KTFX 190851 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 251 AM MDT Fri Jul 19 2024 .SYNOPSIS... Persistent upper level ridging over the Western US will help to maintain well above normal temperatures and overall dry conditions across Southwest through North Central Montana through the middle of next week. && .DISCUSSION... Today through Saturday...upper level ridge will amplify through the first half of the weekend, with continued well above normal temperatures and overall dry conditions expected across Southwest through North Central Montana. Surface winds beneath this amplifying ridge will remain overall light; however, infrequent wind gusts during peak mixing may approach 15 to 25 mph. While most locations will remain dry through the timeframe, isolated to scattered showers and thunderstorms will be possible during the afternoon and evening hours, most notably over the higher terrain on both days and east of a Lewistown to Havre line on Saturday. Primary threat from any shower or thunderstorm will be gusty and erratic winds given inverted-V soundings. Sunday through Wednesday...ensemble clusters continue to favor strong upper level ridging residing over much of the Western CONUS, with longwave troughing over the Pacific Northwest and western seaboard of Canada. This upper level ridge will help maintain well above normal temperatures and overall dry conditions across Southwest through North Central Montana through the period. Leading mode of uncertainty through the timeframe will be position and/or timing of the aforementioned trough over the Pacific Northwest and western seaboard of Canada, which will ultimately impact when the upper level ridge over the Northern Rockies begins to be broken down. Thursday through next Friday...ensemble clusters favor the breakdown of the upper level ridge over the Northern Rockies as a longwave trough slides east from the western seaboard. Leading mode of uncertainty through the period will be the position and/or timing of the longwave trough, which will ultimately impact how long the above normal temperatures last across Southwest through North Central Montana. None-the-less, ensemble model guidance does support a brief and slight "cool down" towards the end of the work week as upper level heights fall, but this may only result in daytime highs reaching the mid- to upper 80s vs the preceding 90s to near 100 degrees. Additionally, as the ridge breaks down, expect southwest to west winds to increase. - Moldan && .AVIATION... 19/06Z TAF Period Showers and thunderstorms have diminished across the region leaving only lingering mid and high level clouds across portions of the hi- line and southwestern Montana. VFR conditions are expected to prevail through the TAF period with generally light and variable winds. Additional showers and a few thunderstorms look to form around terrain again Friday afternoon, but confidence in any impacts to terminals across Southwest and Central Montana is far too low at this time to include mention in TAFs. Density altitude concerns from hot temperatures, as well as slant range visibility concerns due to wildfire smoke will continue this TAF period. -AM/thor Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PRELIMINARY POINT TEMPS/POPS... GTF 93 60 94 59 / 0 10 10 0 CTB 92 55 94 57 / 20 10 20 10 HLN 98 60 98 60 / 0 0 10 0 BZN 95 54 95 54 / 10 0 10 10 WYS 86 42 85 42 / 10 10 20 10 DLN 90 52 90 51 / 0 0 10 0 HVR 96 61 97 60 / 10 10 20 20 LWT 88 56 88 55 / 10 10 30 20 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls