044 FXUS65 KTFX 161040 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 440 AM MDT Wed Aug 16 2017 ...Updated Aviation Discussion... .SYNOPSIS... A west to northwest flow aloft is developing over the region. As a result, expect several days with little to no precipitation. Afternoon temperatures will be on the warm side...with highs generally in the mid to upper 80s. && .DISCUSSION... Today through Friday...West to northwesterly flow aloft will prevail over the region for the next few days. This, along with very dry air across the region, will present fire weather issues through the remainder of the week into the weekend. (See the fire weather discussion for details.) A passing front tonight will result in northwesterly winds Thursday over north-central MT along with temperatures returning to near seasonal normals. Upper ridging combined with increasing west-southwest winds and resultant compressional warming will result in seasonably warm and very dry conditions Friday. CC Friday night through Tuesday night...Primary concerns in the long term will be a wind shift and breezy conditions for the day on Saturday. Otherwise, the remainder of the long term looks to be fairly dry (with the exception of some diurnally forced showers/storms) with near normal temperatures for August, as zonal/near-zonal flow develops and remains the prominent upper level feature over the Intermountain West and Northern Rockies. A shortwave over the Intermountain West and Canadian Province of British Columbia Friday evening will translate east through the day on Saturday. At the surface, an area of low pressure will develop and strengthen in lee of the Canadian Rockies in Alberta during the evening hours on Friday, before quickly sliding east/east northeast into the interior of Canada. The aforementioned area of low pressure will drag a cold front across North Central Montana during the morning hours on Saturday. This front will bring a shift in wind direction from westerly (prior to the frontal passage) to north-northwesterly (post frontal). In addition to a shift in wind direction, breezy conditions are expected with sustained winds of 10-15 mph and gusts approaching 25 mph. Following the cold front on Saturday, the remainder of the long term currently looks "quiet". While a few showers/storms can't be ruled out over Southwest Montana during the evening hours on Sunday, believe that any residual cloud cover should translate east/dissipate for the viewing of the upcoming solar eclipse on Monday. With that being said, mostly sunny to partly sunny skies are currently anticipated for the day on Monday, with slight chances for an afternoon shower/storm along the Idaho and Wyoming borders. - Moldan && .AVIATION... Updated 1040z. VFR conditions will predominate with dry conditions expected through the TAF period, with the possible of a narrow corridor between WYS and EKS where an isolated thunderstorm may develop this afternoon or early evening. West to southwest winds at HLN, GTF, CTB, AND HVR may become occasionally gusty in the afternoon. A dry frontal passage overnight tonight will result in increasing breezes out of the northwest across the region. CC && .FIRE WEATHER... A very active fire weather period is in store into the weekend. Evening and overnight forecast model soundings and statistical guidance for this afternoon and early evening suggests a more localized critical fire weather threat with much lower humidity values than initially expected today along a Helena to Great Falls to Havre corridor this afternoon. A passing weather front tonight will result in cooler (and near normal) temperatures for Thursday, however the presence of sufficiently dry air and gusty winds over our Lewistown-area fire districts will result in a decent potential for reaching critical fire weather conditions Thursday afternoon into the evening. Thus, a Fire Weather Watch will be issued for Fire Weather Zones 113 and 115 for Thursday in addition to the Red Flag Warnings for today for the more localized threat for most zones. Moderate downslope flow Friday into Saturday along with a dry frontal passage will result in warm, windy, and very dry conditions. Additional fire weather highlights are likely during this time period as well. In addition, overnight humidity recoveries will only be moderate in many areas with the breezy conditions from tonight into the weekend. CC && .PRELIMINARY POINT TEMPS/POPS... GTF 87 53 84 51 / 0 0 0 0 CTB 82 51 81 49 / 0 0 0 0 HLN 86 54 85 52 / 0 0 0 0 BZN 83 49 83 49 / 0 0 0 0 WEY 72 38 74 37 / 10 10 10 0 DLN 82 48 82 47 / 10 0 0 0 HVR 88 54 85 52 / 0 0 0 0 LWT 85 52 81 51 / 0 0 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from noon today to 9 PM MDT this evening Central and Eastern Lewis and Clark National Forest Areas... Chouteau and Fergus Counties...Eastern Glacier/Toole/Central/Eastern Pondera/Liberty...Helena and Townsend Ranger Districts of the Helena National Forest...Hill and Blaine Counties...Lewis and Clark National Forest Rocky Mountain District-Rocky Mountain Front. Fire Weather Watch from Thursday afternoon through Thursday evening Chouteau and Fergus Counties...Hill and Blaine Counties. && $$ weather.gov/greatfalls