FXUS65 KBYZ 181218 AFDBYZ Area Forecast Discussion...Updated National Weather Service Billings MT 618 AM MDT Mon May 18 2026 .KEY MESSAGES... - Frost/freeze this morning and Tuesday morning, coldest Tuesday morning. Make sure to protect sensitive vegetation. - Cooler and breezy with occasional chances of precipitation today. - Light snow accumulations (an inch or less) over the foothills this morning. Minor impacts to travel are possible. - Periods of light to moderate mountain snow today. Recreation could be impacted by winter conditions. - Another weather system brings the chance of precipitation Wednesday into Thursday. && .UPDATE... After a brief break overnight, light rain/snow is advecting north into southern portions of the area this morning as moisture and weak lift stream north. Expect a cool (highs in the 40s to low 50s), breezy and unsettled day today, with the greatest shower coverage over the southern mountains/foothills and far southeast MT as an upper low lifts north and east into the central Rockies. A few inches of additional snow accumulation is possible in the mountains, greatest on north aspects, with some slushy accumulations into the foothills (inch or less), greatest near the mountains. The Winter Weather Advisory for the Bighorn/Pryor mountains is in effect until noon today. Have updated temperatures and PoPs to latest trends through this evening. STP && .DISCUSSION... Today through Sunday... Today will be cool, breezy, and unsettled under the influence cyclonic flow aloft. With this, high temperatures will be in the 40s to lower 50s with brisk northerly wind gusts in the teens and 20s mph for most, with occasional 30s mph near the mountains and foothills. While there is at least a slight chance (15 percent or greater) of light precipitation across the area today, the best chance of more persistent precipitation is to the south near the Montana-Wyoming state line. With this, snow levels will be low enough to favor a rain and snow mix, with mostly snow during the morning hours over the foothills. This may lead to minor travel impacts for the morning commute along the Beartooth and Red Lodge foothills and the Sheridan foothills. However, accumulations are expected to remain relatively light with additional accumulations up to an inch mainly on grassy surfaces. Slick roads could also develop as temperatures drop below freezing tonight along the foothills. With that said, the Winter Weather Advisory remains in effect for the Beartooth and Red Lodge foothills to accommodate the potential for additional, potentially more robust snow shower development this morning. Precipitation gradually comes to an end late today, lingering the longest over far eastern Montana. A stray shower or two may even linger into early Tuesday morning over Fallon and Carter Counties (up to a 15 percent chance). Tuesday will be warmer with high temperatures in the 50s and 60s. While most areas will remain dry under shortwave ridging aloft, an isolated shower or two is possible over the mountains west of Billings during the afternoon (10 to 20 percent chance). Wednesday into Thursday, the chance of precipitation returns as another weather system and associated cold front move through the region. This cold front, expected to drop through the area sometime late Wednesday into early Thursday, looks to bring decent frontogenesis that could support at least scattered precipitation. With this, the chance of seeing any precipitation is currently 40 to 80 percent, greatest over south-central Montana and north-central Wyoming where upslope enhancement looks to be in play. The one potential issue to watch is that models are starting to show the system may split. If this happens, the best energy could dive south and limit the precipitation potential over our area. At this time though, models continue to provide enough frontogenesis and upslope enhancement to favor precipitation. As far as the precipitation type goes, precipitation would mostly be rain for the lower elevations and snow in the mountains with snow levels around 7000 feet. Friday into the weekend looks to remain unsettled with northwesterly flow aloft. While temperatures are currently advertised to warm back into upper 70s and 80s this weekend, temperatures may trend slightly cooler (more in the 70s) as potential weather systems moving through the northwesterly flow aloft are picked up in the models. Arends .AVIATION... Snow showers will continue to obscure the mountains at times today. Scattered rain/snow showers will impact foothill locations at times as well (KLVM and KSHR), with isolated rain showers over the plains. MVFR to local IFR conditions are possible with the showers, with widespread MVFR ceilings over the area as well. Look for conditions to gradually improve during the afternoon and evening with lifting ceilings and decreasing shower coverage for most areas. As skies clear and winds decrease overnight, some patchy fog is possible (20% chance) for central and eastern valleys. STP && .PRELIMINARY POINT TEMP/POPS... Tdy Tue Wed Thu Fri Sat Sun ------------------------------------------------------- BIL 050 029/067 043/071 043/063 042/071 045/079 050/084 2/W 10/U 01/B 75/T 11/B 00/B 01/B LVM 048 025/062 036/065 036/061 036/068 040/076 044/080 4/W 10/B 02/W 85/T 12/T 11/B 11/N HDN 050 026/067 037/073 041/064 039/072 042/079 047/083 2/W 10/U 01/B 65/T 22/T 10/B 01/B MLS 048 030/064 040/073 043/065 041/071 043/078 048/082 2/W 20/U 01/B 44/W 11/B 10/B 11/B 4BQ 045 029/062 038/072 043/062 040/068 043/076 048/081 5/W 20/U 00/U 26/W 22/W 10/B 01/B BHK 046 029/059 035/072 039/064 038/068 042/075 046/081 4/W 20/B 01/B 34/W 32/W 21/B 11/B SHR 043 024/060 031/067 036/058 033/067 036/075 040/080 8/W 10/U 01/U 47/T 23/T 11/B 01/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...Winter Weather Advisory in effect until noon MDT today FOR ZONE 171. WY...Winter Weather Advisory in effect until noon MDT today FOR ZONE 198. && $$ weather.gov/billings