771 FXUS65 KBYZ 280951 AFDBYZ Area Forecast Discussion National Weather Service Billings MT 251 AM MST Sat Jan 28 2017 .SHORT TERM...valid for Tdy and Sun... Weak energy moving through NW-N flow aloft over the area will bring the possibility of snow showers over the mountains and eastern areas today into this evening. Otherwise, mainly dry weather can be expected through the weekend with heights building aloft as ridging intensifies across the West. Strong surface high pressure over the Great Basin and the Northern Rockies west of the Divide, with lower surface pressure across the plains will continue to support strong west-east downslope gradients through the weekend. Have gone ahead and issued a High Wind Warning for the Northern Sweet Grass County zone including Big Timber through early Sunday where westerly wind gusts of 50 to 60 mph will be possible. The warning may need to be extended further out in time. Also, have held off on issuing a wind warning for the Southern Wheatland zone at this time as the strongest winds look to remain along the I-90 corridor. This will need to be monitored. Heading into Sunday night/early Monday, gradients become oriented more south-north, which would support stronger winds in the gap flow areas around Livingston and Nye. Wind highlites may be needed for these areas. High temperatures will range from the 30s and 40s today, warming further on Sunday with highs in the 40s to near 50 degrees possible for most locations. STP .LONG TERM...valid for Mon...Tue...Wed...Thu...Fri... Heights fall across the area on Monday as upper low drops into the Great Lakes region and drags a cold front into the area. Colder air dams up against the higher terrain by Monday night and remains substantially in place through next weekend. Pacific moisture feed over-running this cold air will bring a prolonged period of persistent light snow to the area. The heaviest snowfall is likely to occur Monday night into Tuesday with advisory type accumulations possible from Billings west. Accumulations of around an inch or so per day seems reasonable from Tuesday night through Friday based on current model trends. Depth of the cold air will determine where the heaviest band of snow will develop, along the most favorable isentropic ascent region. Right now that appears to be along a Harlowton to Billings to Ashland line, but if cold air deepens it would shift southwest, shallower and a shift to the northeast would be the result. Temperatures will drop back below average with highs in the 20s, and lows in the teens to single digits through the week. Chambers && .AVIATION... VFR ceilings will persist across the forecast area today. For areas east of Billings occasional MVFR ceilings with areas of light snow can be expected. Breezy conditions can be expected most areas today with gusts of 20 to 30kts, though higher gusts of 35 to 50kts are expected over the western foothills including the Livingston, Big Timber, and Harlowton areas. Chambers && .PRELIMINARY POINT TEMP/POPS... Tdy Sun Mon Tue Wed Thu Fri ------------------------------------------------------- BIL 040 030/045 031/044 022/027 017/025 013/024 014/028 1/N 00/N 00/N 46/S 65/S 43/S 34/S LVM 040 027/047 028/042 024/032 020/030 017/031 019/033 1/N 00/N 01/N 66/S 65/S 43/S 35/S HDN 037 025/042 024/041 018/027 013/024 009/024 010/028 1/N 00/N 00/B 36/S 65/S 43/S 34/S MLS 035 024/039 026/038 018/027 013/022 009/021 007/022 2/J 20/B 00/B 23/S 33/S 33/S 33/S 4BQ 036 026/042 026/040 012/027 012/024 007/023 007/027 2/J 10/B 01/B 23/S 33/S 33/S 22/S BHK 034 024/038 026/036 016/024 006/020 006/019 006/020 2/J 20/B 01/N 12/S 22/S 33/S 32/S SHR 038 024/045 024/042 015/027 012/027 011/029 012/030 1/B 00/B 01/B 34/S 33/S 32/S 23/S && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...High Wind Warning in effect until 6 AM MST Sunday FOR ZONE 41. WY...None. && $$ weather.gov/billings