587 FXUS65 KTFX 291757 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 1150 AM MDT Mon Jul 29 2019 Aviation Section Updated. .UPDATE... Skies are clear across our forecast area this morning, except for the MT/ID border where clouds are peeking over the line from showers in ID. Expect scattered thunderstorms over Southwest Montana through late afternoon. Only minor updates were posted to the forecast to better capture observed trends. && .SYNOPSIS... Upper level high pressure ridge will be over the region for very warm to hot conditions through the week. Isolated to scattered showers and thunderstorm are possible across portions of central and southwest Montana each day, mainly during the afternoon and evening hours. Smoke and haze from area wildfires could reduce visibility at times. && .AVIATION... Updated 1140 AM MDT Mon Jul 29 2019 (18Z/29 TAFs) Isolated/scattered thunderstorms expected across Southwest MT after 18Z and continuing through about 03Z Tuesday. Remainder of the forecast area will be mostly clear to partly cloudy and dry with widespread VFR conditions. However, areas of smoke/haze from wildfires could reduce visibilities to MVFR conditions at times, especially near KHLN. && .PREV DISCUSSION... /ISSUED 525 AM MDT Mon Jul 29 2019/ A high pressure ridge aloft will continue to build over the Great Basin and Four Corners Region early in the week with southwest flow aloft prevailing over Montana. A disturbance in the flow aloft will move into far southwest Montana today, bringing scattered wet and dry thunderstorms, mainly south of a line from Helena to White Sulphur Springs. Remainder of the forecast area can expect mostly clear to partly cloudy skies with very warm temperatures and breezy winds. Somewhat stronger winds are expected across north central Montana on Tuesday. These windy conditions combined with very low humidity could bring an increasing risk for critical fire weather conditions to this region by afternoon. This will continue to be monitored for possible highlights. Later in the week, models indicate that the upper level ridge will slide eastward into the southern and central Rocky Mountain Region. This pattern will allow for an increasing amount of monsoon moisture to be picked up and brought into Montana by southwesterly flow aloft. By Friday, models suggest that an upper level trough will move into British Columbia and the Pacific Northwest coast. This system is expected to flatten the upper ridge somewhat as it moves northeastward into southern or central Alberta by Saturday night. Model solutions diverge for Sunday and Monday as the GFS weakens this low and moves it eastward through Canada leaving Montana beneath zonal flow and allowing cooler Canadian air to filter into the state. Meanwhile, the ECMWF develops a second low over southern British Columbia with shortwave ridging developing over Montana for much warmer conditions. The official forecast will use the National Blend of Models (NBM) which trends toward the GFS with high temperatures cooling into the 80s for the weekend and early next week. Isolated to possible scattered showers and thunderstorms will remain possible during this period as well. mpj && .PRELIMINARY POINT TEMPS/POPS... GTF 89 57 90 56 / 0 0 10 10 CTB 84 50 87 52 / 0 0 0 0 HLN 89 56 88 54 / 10 40 20 20 BZN 87 52 88 51 / 30 40 10 20 WEY 79 43 83 43 / 30 50 20 20 DLN 83 51 85 49 / 40 40 20 10 HVR 90 56 94 57 / 0 0 10 10 LWT 84 55 88 55 / 0 20 20 20 && .TFX WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from 3 PM this afternoon to 9 PM MDT this evening Helena and Townsend Ranger Districts of the Helena National Forest. Red Flag Warning from 1 PM this afternoon to 9 PM MDT this evening Deerlodge/Western Beaverhead National Forest...Eastern Beaverhead National Forest. && $$ http://www.weather.gov/greatfalls