052 FXUS65 KTFX 151120 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 520 AM MDT Tue Aug 15 2017 ...Aviation Section Updated... .SYNOPSIS... Showers and thunderstorms will be possible once again today across Southwest and into portions of Central Montana. Areal coverage of these showers and storms is expected to be significantly lower than on Monday, with only light precipitation amounts generally expected. Temperatures will remain below normal today, before climbing to near normal values for August on Wednesday. && .DISCUSSION... Today through Wednesday...broad troughing over the Northern Rockies and Northern High Plains will persist for the next 18-24 hours, before near-zonal flow overspreads the region for the day on Wednesday. Showers and thunderstorms will once again be possible over Southwestern Montana and into portions of Central Montana, however, areal coverage today is expected to be significantly lower than yesterday. Believe that today's shower/storm activity will be more orographically focused despite continued cyclonic flow over the region, mainly because the synoptic ascent and available moisture is very weak/limited. High temperatures will remain below normal for today, but should be a degree or two warmer than Monday. Precipitation chances will gradually come to an end by the evening hours, as the H700 and H500 flow becomes more zonal in nature. This upper level pattern will continue into the day on Wednesday, which should bring dry and warming conditions to all of North Central and Southwest Montana. High temperatures will climb to and/or slightly above normal for the day on Wednesday. With westerly flow present in the mid levels, downsloping effects are expected across North Central Montana, which will cause Minimum Relative Humidity values to fall well below 20 percent. While winds will become brisk during the afternoon as mixing occurs, am not currently expecting frequent wind gusts in excess of 25 mph. None-the-less, elevated fire weather concerns will exist for the day on Wednesday due to the very dry air expected. Wednesday night through Thursday...a quick moving shortwave is expected to dive southeast from Canada during the late evening hours on Wednesday/morning hours on Thursday. This disturbance is generally expected to be dry in nature, however, will bring a noticeable wind shift to the region. Current thinking is that a weak surface front will begin to dive southeast across North Central Montana during the late morning/early afternoon hours on Thursday, which will cause westerly winds to turn to the northwest. Sustained wind speeds of 10 to 15 mph and gusts approaching 25 mph are currently expected during the afternoon hours on Thursday across North Central Montana, which when combined with critical to near critical relative humidity values, will lead to another day of at least elevated fire weather concerns. - Moldan Thursday Night through Monday...Generally dry conditions along with moderating temperatures are expected for the remainder of the work week. By the weekend, the pattern appears favorable for increasingly breezy conditions, especially over the plains of central MT. This may come after a warm/dry period and certainly bears watching for at least elevated fire concerns. In addition, a wind shift with a cold front may add to the concerns Saturday night and/or Sunday. Current sky cover forecasts depict mostly favorable conditions for solar eclipse viewing Monday with dry conditions expected across central and southwest Montana, but this will continue to be monitored in the hopes of achieving greater confidence as the event approaches. MARTIN/CC && .AVIATION... Updated 1120Z. VFR conditions are expected throughout the 1512/1612 TAF period for all terminals across Southwest and North Central Montana. A few showers and thunderstorms are possible through the afternoon hours across Southwest and into portions of Central Montana, however, no impacts to terminals are currently anticipated. - Moldan && .PRELIMINARY POINT TEMPS/POPS... GTF 80 48 85 52 / 10 10 0 0 CTB 76 45 82 51 / 10 10 0 0 HLN 82 50 84 52 / 10 10 0 0 BZN 77 46 82 48 / 20 10 0 10 WEY 66 37 72 38 / 20 10 10 10 DLN 76 46 80 47 / 20 10 0 0 HVR 79 50 87 52 / 10 10 0 0 LWT 77 49 82 51 / 10 10 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ weather.gov/greatfalls