FXUS65 KTFX 020329 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 928 PM MDT MON AUG 1 2016 .DISCUSSION... No update necessary tonight. High pressure continues to provide dry and stable conditions. MODIS satellite imagery continues to show some smoke from Idaho wildfires making its way into southwest Montana. Temperatures look good. && .AVIATION... Updated 2335Z. High pressure aloft will continue to provide dry and stable conditions. West to northwest winds have been gusty at some locations but will decrease after 03z. VFR conditions prevail. && .PREV DISCUSSION...Issued 336 PM MDT MON AUG 1 2016 Monday afternoon through Wednesday...The upper level low over northern Saskatchewan will continue to lift NE into Hudson Bay tonight allowing a s/w ridge to briefly build into Montana. Outside of an isolated shower or storm near the Little Rockies this afternoon, this should keep the forecast area precip-free through Tuesday morning. Late Tuesday into Wednesday, a potent upper level low will move through the region. At the SFC, an area of low pressure and associated cold front will move across the CWA Tuesday afternoon/evening. Moisture with this low looks limited at this time and mainly confined along and north of the low track (ie. from the Hi-Line north into Canada). How much moisture can be pulled into our northern counties remains uncertain and may ultimately determine whether we can get much t-storm development on this side of the International Border. That said, forecast soundings indicate more than adequate shear in that area late Tuesday into Tuesday evening, so any storm that can develop will have the potential to become strong to severe with damaging winds and large hail the main threats. Again, though, the threat may be tampered by how much moisture can be pulled into the area. The other issue with this front will be the wind. A lighter south/SE wind will develop ahead of the low Tuesday afternoon, then quickly shift to the west late Tuesday afternoon through Tuesday night from west to east. Across the plains of north- central Montana, wind gusts of 30-45 mph are likely. The strong winds combined with drier air may lead to some elevated fire concerns. However, at this time there is some uncertainty regarding just how dry it will get and for this reason, will hold off on any fire weather highlights for Wednesday afternoon. Something to keep a close eye on, though. Temperatures will warm to above normal Tuesday afternoon, then drop down below normal on Wednesday behind the front. Martin Wednesday night through Monday...Upper level low looks to move east across southern Canada Wednesday night...ending breezy winds and chances for scattered showers and thunderstorms from west to east across the forecast area. Ridge of high pressure with weak and dry flow moves across the region for Thursday and Friday. Temperatures will warm each day back into the 80s...with the mentioned dry air dropping afternoon RH values back into the teens to low 20s. No precipitation is expected for Thursday. Friday will see a switch to a more south southeasterly flow...possibly gusty at times. This southerly flow will also bring with it a slight increase of monsoonal moisture. Only southern parts of the CWA will have enough to support chances for thunderstorms on Friday...but this southerly flow could start to prime the atmosphere for this weekend. A closed upper level low in western Canada extends a large trough across the west coast for Saturday. This will help bring more monsoonal moisture across the region. Along with that...se flow continues at the sfc advecting more moisture into the region. With low to moderate instability...the upper level disturbance...and increased moisture...isolated to scattered thunderstorms will be possible across much of the CWA on Saturday. The upper level trough will then push across the region on Sunday. A developing sfc low in southern MT could even tap into some limited gulf moisture across eastern portions of the CWA...possibly bringing dewpoints in the 50s to low 60s. Much like Saturday...isolated to scattered thunderstorms will be possible across much of the CWA. Exact timing and location of these weekend storms is difficult to predict this far out...so put widespread slight chance in across the area. With only moderate levels of shear...a few isolated stronger storms may be possible this weekend...and mainly confined to eastern portions of the CWA where models are indicating higher dewpoints may enter into the CWA. The trough will then move northeast through Montana on Monday...keeping a slight chance of showers and thunderstorms over the forecast area. Similar temperatures to those previously mentioned on Thursday and Friday will continue through the weekend into Monday. Anglin/Coulston && .FIRE WEATHER... On Tuesday, temperatures will become quite warm with continued very dry air, especially in the central and southwest fire zones (117 and 118). However, a light easterly flow on the northern and eastern plains (zones 112, 113, 115) should keep humidity values there a bit higher. A cold front is then expected to sweep east across the region Tuesday evening/overnight. Winds may increase some in the deeper mixed pre-frontal environment late Tuesday afternoon, but at this point the timing of the front is not optimal for gusty winds during the peak afternoon heating period. Gusty west winds will sweep east behind the front Tuesday night through Wednesday. Temperatures cool and humidity improves Tuesday night through Wednesday, though some locations across SW MT may still see afternoon RH fall to near 20% Wednesday afternoon. Because the driest conditions and strongest winds do not seem to coincide at this time, am not anticipating a need for fire weather highlights at this time, but will continue to monitor the situation for possible timing adjustments. Hoenisch/Coulston && .PRELIMINARY POINT TEMPS/POPS... GTF 51 90 53 75 / 0 0 10 10 CTB 46 85 52 68 / 0 10 20 20 HLN 54 94 57 79 / 0 10 10 0 BZN 48 92 49 80 / 0 10 10 0 WEY 42 81 45 73 / 10 10 10 0 DLN 48 88 48 78 / 0 10 0 0 HVR 50 91 57 75 / 0 0 20 20 LWT 53 87 54 75 / 0 10 10 10 && .TFX WATCHES/WARNINGS/ADVISORIES... && $$ weather.gov/greatfalls