989 FXUS65 KTFX 172359 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 559 PM MDT Tue Sep 17 2019 ...UPDATED AVIATION DISCUSSION... .SYNOPSIS... A cloudy and cool day, with areas of rain, will transition into a cool night with clearing skies across much of the state. Much of central Montana will have high temperatures 5 to 10 degrees warmer on Wednesday, though eastern Montana will be somewhat cooler. The next weather system will bring increasing rain chances west of the Divide on Wednesday, with clouds and rain spreading east Wednesday night into Thursday. && .DISCUSSION... Tonight through Wednesday... A shortwave trough transiting across the northern Rockies this afternoon and evening will bring some continued shower activity to southern and central parts of the CWA through around 00z. The greatest risk will remain from the Little Belts east into Fergus County. A few rumbles of thunder can't be ruled out over Fergus County, either Clearing expected from west to east this evening, with a mostly to partly clear night with diminishing winds expected as transient upper ridging slides across the region. This ridging will help boost temperatures 5 to 10 degrees higher tomorrow compared to today, though this may depend greatly on how much cloud cover spills east across the Divide from the approaching trough over the Pac NW. -Kredensor Wednesday night through next Tuesday... As the next trough moves east into the Rockies, it will also deepen some, and some raw fall days are likely in store later this week. Between Thu and Sat, the entire CWA is likely to see at least some rain, but the best chances for more widespread and heavier rain definitely remain over the central and southern parts of the CWA. In these areas, a half inch to an inch of QPF is currently in the forecast, while areas north of a line from Augusta to the Big Snowy Mountains will likely see lesser rain totals. The higher elevations of the SW MT ranges, especially the Madisons, Tobacco Roots, and Pioneers, could pick up a decent early season snowfall, so outdoor recreation concerns in these areas should definitely keep up to date on the latest forecasts. From Sun onward, the models start to diverge significantly in their solutions for the upper level pattern and resulting surface weather features. While most agree on ridging and clearing for Sun and Sun night, with another upper low digging into the Desert Southwest, there is minimal agreement beyond that on how the pattern will unfold over Montana. As a result, the temperature forecast is quite uncertain at this point early next week, and POPs were kept under 50 percent until some more clarity can be had through better model agreement and run-to-run consistency. -Kredensor && .AVIATION... Updated 0600 PM MDT Tue Sep 17 2019 (18/00Z TAFs) Showers may linger east of a line from KHVR to KLWT through the early evening, then end across the area by late this evening. Some MVFR ceilings may linger for area sites this evening with a general return to VFR conditions overnight tonight. Some patchy fog will also be possible late tonight into Wednesday morning, although confidence is too low to include in TAFs at this moment. Wednesday will then see VFR conditions with increasing clouds throughout the day and some breezy winds. Chances for showers then return Wednesday night into Thursday. Anglin && .PRELIMINARY POINT TEMPS/POPS... GTF 43 70 45 60 / 0 10 50 40 CTB 40 63 41 60 / 0 40 70 30 HLN 42 70 44 61 / 0 30 70 70 BZN 38 72 41 63 / 10 0 40 50 WEY 32 63 31 59 / 30 0 20 40 DLN 38 66 41 58 / 0 20 60 70 HVR 42 74 47 67 / 20 0 40 30 LWT 40 72 43 61 / 20 0 10 30 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls