240 FXUS65 KBYZ 232159 AFDBYZ Area Forecast Discussion National Weather Service Billings MT 259 PM MST Wed Dec 23 2020 .DISCUSSION... Tonight through Friday... Generally minor changes for the short term forecast with dry conditions and unseasonably warm temperatures to prevail through the period. Biggest concern through the period will be strong winds across western zones, as klondike chinook takes shape overnight tonight, and persists through the remainder of the week. High amplitude ridging continues to develop along the Pacific coast today, and slides eastward this evening and tonight. We will transition to dry anticyclonic flow aloft through the remainder of the day...resulting in the onset of a klondike chinook. Westerly winds have redeveloped along our western foothills this afternoon. Additionally, the surface gradient will tighten quite a bit, further enhancing downslope flow. The orientation of the gradient favors strongest gust in Big Timber and Harlowton. Expect to see gusts around 50 mph in these areas, with a chance of near 60 mph gusts. Gusty winds will persist into through Christmas Eve and Christmas Day. Winds should help moderate overnight temps and drive daytime highs to around 50 degrees across western zones, while easternmost zones should see 40s. Did raise forecast daytime highs by several degrees, in line with MET guidance. Not convinced these temps are warm enough with ridging and winds coming into play. Lows tonight will be in the 20s West and teens to single digits East. Persistent downslope warming will push daytime highs to the 50s in many locations for Christmas Eve and Christmas Day. Winds will also moderate overnight lows, with upper teens to upper 20s expected each night. Gilstad Saturday through Wednesday... Saturday falling heights over the region in response to a series of shortwaves flowing over the area from the Pacific Northwest. 2 part cold front will see a Pacific front move through Saturday morning with a polar front arriving late Saturday afternoon. This should yield shower activity during the day favoring the mountains but by evening a more upslope flow will bring a broader light snow to much of the lower elevations. Forcing is not deep so do not expect significant precipitation rates but an inch or two of snow may be possible, favoring areas south of Billings. Temperatures will be cooler on Saturday and even cooler on Sunday as the upslopish regime limits mixing. Most likely period of snow will be Saturday night through Sunday morning. By Monday morning leeside troughing beings to develop so upslope gradients weakens. Upper level flow pattern is weak and more of a split flow regime with a strong system diving into the Great Basin. This energy weakens any downslope gradients so Monday and Tuesday will be cool but no precipitation expected. Will keep an eye on how the Great Basin system ejects as it becomes a leeside cyclone but not sure at this time if its track will be far enough north to impact MT or northern WY. borsum && .AVIATION... Mostly clear skies and VFR through the period. Increasing winds along the foothills this afternoon through the evening becoming strong impacting KLVM. borsum && .PRELIMINARY POINT TEMP/POPS... Thu Fri Sat Sun Mon Tue Wed ----------------------------------------------------------- BIL 024/051 027/051 027/043 025/034 018/033 016/032 017/034 00/N 00/B 01/E 43/S 10/B 00/B 00/B LVM 020/046 023/050 026/042 027/037 017/034 014/032 014/033 00/N 00/N 03/S 42/S 10/B 00/B 00/B HDN 020/051 020/051 019/045 021/034 014/034 011/032 012/035 00/B 00/B 01/E 43/S 10/B 00/B 00/B MLS 016/047 021/048 018/039 017/027 011/030 011/029 010/030 00/B 00/U 00/E 32/S 00/B 00/B 00/B 4BQ 016/047 021/052 019/043 020/029 013/032 013/030 012/032 00/B 00/U 00/E 34/S 00/B 01/B 00/B BHK 009/041 019/047 016/038 014/024 006/026 009/027 008/028 00/B 00/U 00/E 22/S 00/B 00/B 00/B SHR 014/051 020/055 020/045 021/034 012/034 011/032 009/033 00/U 00/B 01/E 44/S 10/B 01/B 00/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings