414 FXUS65 KBYZ 062058 AFDBYZ Area Forecast Discussion National Weather Service Billings MT 158 PM MST Sun Nov 6 2022 .DISCUSSION... Tonight through Tuesday night... Our region is in between systems today with high pressure aloft prevailing over the northern Rockies and nearby high plains. Mid level flow slowly backs to the southwest tonight as an upper low deepens off the Pacific NW coast. Pacific moisture will start to stream into western zones late tonight into Monday with some light snow possible, mainly over the Absaroka/Beartooth Ranges. Lows tonight will be in the teens and 20s. There is a broad pool of energy and mid level moisture that tracks over our CWA Monday morning in the southwest flow. This may produce some virga or sprinkles, though a brief period of isentropic lift over our far eastern zones may produce some light precipitation. By Monday afternoon this passes to the north leaving our central and eastern zones dry. However, Monday will see a corridor of moisture and ascent on the front side of the trough set up just to the west of the area, but will also affect our Beartooth/Absaroka mountains and perhaps portions of Park County and the Crazies at times. A few inches of snowfall is expected through Monday in the high country. Highs Tuesday will range from upper 20s west to lower 50s in the southeast. Monday night and Tuesday...The relatively narrow corridor of precipitation slowly shifts east to also cover our western foothills and nearby plains in addition to our southwest mountains. Cross sections show some shallow easterly upslope into Yellowstone County. There does remain uncertainty though, models are not in good agreement as to the eastward extent of the precipitation, and am a little suspect if the precipitation is able to remain heavy or become more scattered in nature as the upper low off the NW coast begins to sink south along the coast toward California by Tuesday, thus possibly losing some of it influence over our region. The fetch of moisture should remain pretty steady for at least our SW mountains and where our Winter Storm Warning remains in place. At this time NBM 4.1 probs have a about 60 percent chance of 12 inches or greater in the SW mountains through Tuesday. Models may also not be taking into account powerful orographics in this pattern over our southwest facing slopes. We will upgrade our watch to a Winter Storm Warning for the Absaroka/Beartooth Mountains Monday through 3 pm Tuesday. The heaviest snow will likely be Monday night. Future shifts will monitor the foothills in Park, Sweetgrass and Wheatland counties for a possible Winter Weather Advisory Monday night into Tuesday with two to four inches of accumulation possible if that precipitation corridor does shift east. Billings could see up to around an inch. Highs on Tuesday will be generally in the 20s. Lots of uncertainty by Tuesday night into Wednesday, but there is potential for another shot of heavy snow in the mountains and snow on the plains in a narrow band under the upper jet. Placement of decent snowfall would be difficult to nail down this far out, so widespread shotgun type PoPs are in place for now. BT Wednesday through Sunday... An active pattern is in store for the first part of the extended period as a large trough moves in across the area from the Pacific Northwest Coast. Ensembles are in decent agreement with the mid- level low ejecting east along the Wyoming/Montana border Wednesday night into Thursday. Widespread precipitation is expected Wednesday through Thursday night as this low tracks across the area. Accumulating snow is likely for much of the region with central zones (including Billings) seeing the best chance continue through Wednesday and the eastern zones (east of Billings) Wednesday through Thursday. Current NBM guidance suggests Billings has around a 50% chance of picking up at least 2 inches of snowfall with a 15% chance of seeing 4 or more inches. Areas east of Billings have a little better chance (60%) of seeing at least 2 inches of snow and near a 40% chance of at least 4 inches, especially as you get near the Dakotas border. Depending on exactly where the surface low develops and tracks, portions of the Plains could certainly see some significant snowfall (in excess of a foot not out of the realm of possibility). However, there is significant uncertainty in how this may pan out. Stay tuned for updates. Temperatures will be cold all week with highs in the 20s and 30s. The coldest days are looking to be Wednesday and Thursday, with highs in the teens to lower 20s and lows in the single digits. Temperatures should moderate for the end of the week into the weekend, but highs will remain below seasonal averages. -Mottice && .AVIATION... VFR conditions are expected through the period. SE to E winds continue through tonight around 10 to 15 knots before turning more northerly in the eastern half of the region tomorrow as a weak area of low pressure moves through. -Mottice && .PRELIMINARY POINT TEMP/POPS... Mon Tue Wed Thu Fri Sat Sun ----------------------------------------------------------- BIL 023/040 019/024 013/021 010/021 007/027 008/028 010/027 11/E 65/S 65/S 63/S 20/U 01/B 11/B LVM 017/041 016/028 009/025 009/031 009/034 010/036 012/036 35/O 97/S 77/S 63/S 10/U 01/B 21/B HDN 022/045 017/026 012/025 009/022 002/027 003/028 004/027 01/E 43/S 65/S 64/S 20/B 01/B 11/B MLS 019/046 021/028 016/024 010/019 002/019 001/021 004/022 02/S 11/E 44/S 65/S 20/B 00/B 11/B 4BQ 021/056 022/031 017/030 013/021 005/024 005/027 007/026 02/O 00/E 32/S 65/S 21/B 00/B 11/B BHK 014/044 022/032 016/027 011/020 001/019 901/022 003/022 02/S 00/E 33/S 66/S 31/B 00/B 01/B SHR 018/054 017/032 013/032 011/025 007/032 008/035 009/032 11/B 12/S 54/S 75/S 20/U 01/B 11/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...Winter Storm Warning in effect from 6 AM Monday to 3 PM MST Tuesday FOR ZONE 67. WY...None. && $$ weather.gov/billings