876 FXUS65 KBYZ 030359 AFDBYZ Area Forecast Discussion...Updated National Weather Service Billings MT 859 PM MST Sat Feb 2 2019 .UPDATE... Cold front has pushed into Judith Gap and temperatures have fallen from the mid 40s early this evening to the teens this hour there. Front should push into Billings by around 10 pm. Adjusted temperatures to account for frontal timing. Adjusted PoPs a bit as radar was filling in north and east of Billings. Latest model runs have the bulk of the heavier snow occuring later tonight and into the early part of the day Sunday. Current highlights look good. TWH && .SHORT TERM...valid for Sun and Mon... Strong cold front moving southward through northern Montana driven by northerly flow aloft over northwest Canada while southwest flow aloft over southern Montana keeping mixed conditions and producing gusty winds along the foothills. Front is expected to move through the forecast area between 8 PM and 2 AM though it may slow as it begins to move through Sheridan County Wyoming. Upslope and moist air allows light snow to be produced by the arctic but expect intensity to pick up as a shortwave tracks into the area Sunday morning. 700mb inflection from this wave generally follows a track from Dillon to Lewistown which means the better lift for heavier snow will be north of and along the Musselshell River. Current forecasts have zeroed in on this area for the highest accumulations through Sunday night with much lighter shots of snow coming across on Monday. Just as important as the snow is how cold the airmass is behind the front and how the region will see single digit temperatures at best Monday into midweek with near double digit below zero low temperatures. This change occurs quickly and temperatures in the mid 50s this afternoon will fall into the teens by Sunday morning. This is supported by a window of strong northerly winds so the snowfall will be associated with a fair amount of blowing snow through the day on Sunday. Snow will still blow Sunday night as snow ratios increase in the cold air so even though snow will be decreasing it will still be blowing around reducing visibility. Also the falling temperatures will begin producing dangerous wind chills Sunday night. Winter highlights currently in effect look good with having adjusted Judith Gap to start at 8 pm. A couple of areas look to provide local challenges as the terrain begins to impact the movement of the cold air as it begins to slow. Some areas along the foothills with higher elevation may see some rain this evening before the cold deepens up enough to change to snow. Could be some icy spots that develop as a result. Another area that may not see as deep a cold air is Cooke City but the moisture is progged to remain deeper as it does not dry out so heavier snow amounts are possible. Last spot that seems to be a challenge is Sheridan which could see the cold air held up a bit by mountain wave activity so the change to much colder could be delayed until daybreak Sunday. borsum .LONG TERM...valid for Tue...Wed...Thu...Fri...Sat... For Tuesday into next weekend, the pattern is indicating very cold temperatures and snow flurries into next weekend. There is a persistent moist southwest flow that will bring a steady snowfall to the Beartooth Mountains. Cooke City has a potential of receiving significant accumulations over the next week. The plains will also see periods of snow flurries but will accumulate to an inch or less each day of the period. The best chance for snow showers in Billings is going to be Tuesday into Tuesday night. Cloud and snow cover are going to be the challenge of this forecast as any break in the clouds could drop temperatures lower than currently forecasted. The amount of snow cover that is received will also vary those temperatures and potentially lower them as well. Winds appear to be light during this period. High temperatures for Tuesday and Wednesday will struggle to get out of the single digits for much of the area. Moving into Thursday and into next weekend temperatures will warm up into the teens with some locations reaching the low 20's. Lows will drop to below zero through the end of the week. Carrothers && .AVIATION... A cold front moving through KLVM and KBIL by 04z and KSHR by 10z will shift winds to north. There could be gusts 20 to 30 knots as the front moves through. Ceilings will drop to IFR conditions behind the front as snow develops. Localized conditions could drop to VLIFR with the heavier snow. Reimer && .PRELIMINARY POINT TEMP/POPS... Sun Mon Tue Wed Thu Fri Sat ----------------------------------------------------------- BIL 012/016 909/003 906/005 908/007 907/018 001/020 001/017 89/S 73/S 24/S 52/S 10/B 01/B 11/E LVM 022/028 003/020 010/020 003/018 000/024 007/026 008/025 89/S 74/S 36/S 42/S 10/U 01/B 11/B HDN 014/019 909/006 906/007 909/007 910/018 902/022 901/018 69/S 72/S 14/S 42/S 10/B 01/B 11/B MLS 009/013 912/901 911/001 913/901 915/007 908/012 904/012 4+/S 72/S 23/S 32/S 10/B 00/B 00/B 4BQ 023/028 910/006 905/010 907/006 909/013 902/019 000/017 2+/S 71/B 12/S 33/S 20/B 00/B 00/B BHK 017/018 914/903 912/002 912/000 916/005 911/010 906/010 2+/S 92/S 23/S 33/S 20/B 00/B 00/E SHR 023/032 906/016 002/018 904/013 907/019 000/025 002/023 37/S 41/E 13/S 33/S 20/B 00/B 00/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...Winter Storm Warning in effect until noon MST Monday FOR ZONES 28>31-40>42-63. Winter Weather Advisory in effect until noon MST Monday FOR ZONES 32>39-56>58-64>66. Winter Storm Warning in effect until 6 PM MST Monday FOR ZONES 67-68. WY...Winter Weather Advisory in effect until noon MST Monday FOR ZONE 99. && $$ weather.gov/billings