965 FXUS65 KTFX 100948 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 348 AM MDT Tue Jul 10 2018 .SYNOPSIS... A cold front sweeps across the region this afternoon bringing windy conditions with scattered showers and storms. Some storms could become strong to severe with very large hail and damaging winds, especially east of Great Falls. && .DISCUSSION... Today through this evening...A leading warm front has moved north across the area well ahead of an approaching strong upper level disturbance, resulting in a pronounced warm sector with increasing instability and low-level moisture. A few showers and weak thunderstorms have developed early this morning and this trend should continue into the late mornings hours. By this afternoon a cold front moves across the region and will help to trigger strong to severe thunderstorms, especially as instability, moisture, and vertical wind shear increases substantially. Very large hail looks to be the primary threat across parts of north- central and central Montana, with isolated damaging wind gusts also possible. There is also is a slight tornado risk over our far northeast counties along the international boundary where significant low-level backing of near-surface winds is possible, but the greater risk will be north of the international boundary. Torrential rainfall and localized flash flooding are also possible. At this time, the best window for thunderstorms looks to span from late morning through the early evening before the threat moves into the eastern half of the state. Wednesday through next Sunday...A drier pattern takes hold Wednesday and Thursday as zonal flow aloft becomes established over MT between a flattened ridge over much of the western United States and a broad trough over much of western and central Canada. Within this broad trough, a strong shortwave disturbance may cross our CWA from northwest to southeast late Friday or Saturday, bringing breezy conditions yet also a much cooler air mass. Showers and thunderstorms are possible along and ahead of this front. Drier weather is then expected to return Sunday with high pressure aloft building-in from the west, but temperatures look to slowly begin an upward climb again to above normal at least by Tuesday of next week. && .AVIATION... Updated 0500Z. Isolated showers and thunderstorms E and SE of the KBZN terminal will dissipate and/or move off to the east by 06z with generally clear skies prevailing through the rest of tonight. Cold front moves east across the region Tuesday afternoon with increasing SW winds ahead of the front at all terminals by early afternoon and wind shift to the west/northwest by Tuesday evening. Scattered thunderstorms are expected along the front Tuesday afternoon, mainly east of a KDLN-KGTF-KCTB with KHVR, KLWT and KBZN most likely to be impacted briefly late Tuesday afternoon. Hoenisch && .PRELIMINARY POINT TEMPS/POPS... GTF 94 55 81 55 / 20 10 0 0 CTB 87 52 78 51 / 20 0 0 10 HLN 94 56 81 55 / 20 0 0 0 BZN 93 52 80 52 / 40 10 0 0 WEY 82 45 77 43 / 20 20 0 0 DLN 89 49 79 50 / 20 0 0 0 HVR 98 58 82 55 / 50 30 0 0 LWT 93 54 75 52 / 50 20 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls