Scientific Forecaster Discussion
000 FXUS65 KTFX 222110 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 306 PM MDT Tue Oct 22 2019 .SYNOPSIS... Windy conditions continue this afternoon, then diminish somewhat as colder air moves into the region tonight, changing rain to snow in many areas. After a cool day on Wednesday, expect warmer and windy conditions to redevelop by Friday. However, it turns sharply colder next weekend, with another round of snow for some areas. && .DISCUSSION... Tonight through Wednesday...Gusty winds developed as expected this afternoon as a front pushed across the CWA. The highest gust reported so far was 81mph at Two Medicine Bridge in East Glacier, but multiple wind gusts over warning criteria of 58mph have been reported along and west of I-15 north of Great Falls. As the mid/high level clouds cleared out early this afternoon, convective showers have developed along the Hi-Line east of I-15, with some lightning reported over parts of Hill and Blaine counties so far. Some of these showers could bring down strong wind gusts. Winds should drop off gradually during the evening hours, though remain gusty overnight as strong pressure rises occur. Rain and snow showers will continue into tomorrow morning as well owing to N-NW'ly flow and a shortwave tracking SE across the area. The best precipitation is likely over the central mountains, where 4 to 8 inches of snow are possible in the Little Belts and Snowys, with little or no accumulating snow expected at lower elevations. Gusty NW'ly winds are expected over the central and northern parts of the CWA, but not expected to approach high wind warning criteria. Precip and winds should both abate Wed night. -Kredensor Thursday through Friday...Shortwave ridging will quickly build over the region for Thursday into Friday. Thus expect much warmer air to move into the region by Friday, thus afternoon temperatures could be a touch higher than currently forecasted. Expect another potential for strong winds. The strong winds on Friday could be a bit more widespread over North Central MT, and high wind highlights might be needed once again. Saturday through Tuesday...The 1st of two strong cold fronts will move southward through the region early on Saturday. Generally expect falling temperatures over much of the region during the day on Saturday, with accumulating snowfall likely in the favored upslope areas of North Central MT. Overall snow amounts look to be around 6 inches in the mountains and an inch or two at lower elevations at this time. It remains cool on Sunday, with the 2nd cold front moving southward through the region Sunday night into Monday. Again, another round of light snowfall is expected with the 2nd cold front, along with colder air moving into the region. It is possible that temperatures on Monday could be quite a bit colder than currently forecasted should this front pan out. Temperatures slowly rebound on Tuesday, as drier air moves back into the region. Brusda/PAN && .AVIATION... Updated 1155 AM MDT Tue Oct 22 2019 (18Z TAF Period) Strong W-WNW'ly winds will remain the main concern this afternoon into the early evening hours, especially for central and northern areas. Wind gusts over 40kts have been common at KCTB and have approached those levels at KGTF, with those winds likely to continue through most of the afternoon. Localized gusts over 50 knots will be possible across north-central Montana through 07z or so. Turbulence and mountain waves may cause some flying concerns, with periods of low level wind shear likely as well. Scattered rain/snow showers and isolated thunderstorms will develop this afternoon and evening, especially where some clearing is allowing surface heating, as a front moves eastward through the region. Overall, much of the area will have mid/high clouds through this afternoon, with lowering ceilings this evening. Brusda/Kredensor && .PRELIMINARY POINT TEMPS/POPS... GTF 34 42 26 51 / 40 40 0 0 CTB 30 42 24 50 / 40 40 0 0 HLN 33 45 24 52 / 20 40 10 0 BZN 29 44 19 50 / 30 40 10 0 WEY 21 33 6 37 / 30 20 0 0 DLN 30 42 21 48 / 10 10 0 0 HVR 32 43 24 52 / 30 30 0 0 LWT 32 37 23 48 / 60 50 10 0 && .TFX WATCHES/WARNINGS/ADVISORIES... High Wind Warning until 7 PM MDT this evening Eastern Glacier... Eastern Pondera...Eastern Teton...Northern Rocky Mountain Front...Southern Rocky Mountain Front. High Wind Warning until 7 PM MDT this evening Cascade...Central and Southern Lewis and Clark...Judith Basin...Meagher. Winter Weather Advisory from 9 PM this evening to noon MDT Wednesday Cascade...Judith Basin...Meagher.