855 FXUS65 KTFX 230939 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 339 AM MDT Thu Sep 23 2021 .SYNOPSIS... A northwest flow aloft will keep temperatures near normal today with scattered clouds passing overhead and only a slight chance of a few light showers. High pressure moving into the area will help clear out the skies on Friday and help warm temperatures to between 10 and 15 degrees above normal for the weekend. However, drying conditions and increasing winds will increase fire weather concerns as well for the weekend. && .DISCUSSION... Today through Friday...Temperatures will be closer to normal today with breezy northwest winds across north central and southwest Montana in the wake of a low pressure system and associated cold front. Scattered mid and high clouds will pass overhead with a few light showers over far southwest Montana this morning and a few light showers late this morning into this afternoon over the Havre area. Winds will also be breezy and out of the northwest this afternoon, but they won't be as strong as yesterday. A high pressure ridge will build into the area overnight into Friday, which should help clear out the cloudiness and cool overnight temperatures closer to normal. Friday should be mostly sunny and a few degrees warmer than today, as surface trough forms just to the lee of the Rockies and brings more southerly winds to the area. Saturday through Tuesday...The high pressure ridge will gradually strengthen and shift more so over Montana during this period. This will keep the area dry and cause temperatures to warm up to 15 degrees above normal some days with low relative humidity. The increasing westerly flow aloft associated with this ridge will shift more southwesterly as a low pressure trough moves onto the Pacific Northwest coast Monday into Tuesday. These winds will also combine with a series of weak cold frontal passages to cause windy conditions at times at lower elevations, especially over the plains, where gusts of 25 to 35 mph will be common during the afternoon hours, and gusts over 40 mph are possible closer to the Rocky Mountain Front. The main impact from this will be increased fire weather concerns, as addressed in the FIRE WEATHER section of this discussion. Wednesday through next Thursday...The Pacific Northwest low pressure trough will move into the area during this mid-week period, but forecast models start to diverge with their forecast solutions. Will therefore stay with the National Blend of Models (NBM) forecast solution for this period, which keeps a good chance for precipitation over the mountains and less of a chance over the plains. This solution should also result in decreased winds and temperatures closer to normal. -Coulston && .AVIATION... 1205 AM MDT Thu Sep 23 2021 (23/06Z TAF period) VFR conditions are expected to continue across the area through at least the next 24 hours. A low pressure trough moving east across the area will move the mid and high clouds out to the east by 12Z, but until then, a few showers over southwest Montana (KBZN KEKS KWYS) may still produce brief wind gusts up to 30 kt. The weakly unstable northwest flow aloft in the wake of the trough will bring scattered to broken mid- and high-level cloudiness back to the area by 18Z, which should persist through at least 06Z. Westerly winds will also become gusty over the plains, but mainly with gusts in excess of 25 kt close to the Rocky Mountain Front. Winds will then shift more northerly over the plains after 00Z as a weak cold front drops south out of Canada. -Coulston Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .FIRE WEATHER... Behind the passage of a cold front, less windy (though still breezy) conditions with slightly higher relative humidity are expected through Friday. However, a dry westerly flow aloft will cause temperatures to warm to between 10 and 15 degrees above normal for Saturday through Monday (and possibly into Tuesday). This will also cause afternoon humidity to fall below 20 percent for most lower elevations, and a series of weak cold fronts will cause winds to increase during the afternoons to 15 to 20 mph with gusts up to 35 mph at times, especially over the plains. These elevated fire weather conditions will increase fire weather concerns, but shorter days are causing shorter periods of peak heating and wind, so the potential for critical fire weather conditions is low at this time. Regardless, we will continue to monitor the situation for possible watches/warnings. && .PRELIMINARY POINT TEMPS/POPS... GTF 72 41 74 47 / 0 0 0 0 CTB 70 38 72 46 / 0 0 0 0 HLN 74 43 77 48 / 0 0 0 0 BZN 71 38 74 41 / 0 0 0 0 WYS 63 27 68 29 / 20 0 0 0 DLN 69 36 74 41 / 0 0 0 0 HVR 73 39 72 45 / 0 10 0 0 LWT 69 40 70 44 / 0 0 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls