FXUS65 KBYZ 191017 AFDBYZ Area Forecast Discussion...Updated National Weather Service Billings MT 417 AM MDT Tue May 19 2026 .KEY MESSAGES... - Frost/freeze conditions this morning. - Patchy freezing fog possible over the plains of eastern Montana this morning (up to a 20 percent chance). - Weather system brings the chance of precipitation to the area Wednesday into Thursday (40 to 90 percent, greatest over south- central Montana and north-central Wyoming). - Moderate chance of seeing at least 0.50 inches of liquid precipitation over south-central Montana and north-central Wyoming Wednesday into Thursday. Snow levels as low as 6 kft. Snow accumulations possible in the high country (moderate to high chance of 4+ inches of snow). - Warmer but still unsettled weather continues into the weekend. && .UPDATE... Temperatures have dropped into the 20s to lower 30s for many areas early this morning as skies have cleared out. While not evident on satellite or webcam images over the area, patchy fog remains possible for eastern valleys into this morning. Have nudged temperatures down a bit for places to account for latest observations and trends. After a cool morning, look for temperatures to rebound into the upper 50s to 60s today. STP && .DISCUSSION... Today through Monday... This morning will be cold with temperatures in the mid 20s to lower 30s under mostly clear skies. Over the plains of eastern Montana, patchy freezing fog is also possible (up to 20 percent chance), mainly where precipitation recently occurred. Any fog that does develop will lift after sunrise. While mostly dry conditions will prevail as temperatures warm into the 50s and 60s during the day today, a few light showers are possible over south- central Montana during the afternoon and evening (~15 percent chance). With this, dry air near the surface will likely favor virga over precipitation making it to the ground, but occasional sprinkles may occur. The dry air near the surface may also result in brief erratic winds with gusts around 30 mph. Wednesday into Thursday, a weather system will bring the chance of precipitation and a brief cooldown back to the area. Ahead of the cold front associated with this weather system, isolated to scattered showers and weak thunderstorms are forecast during the afternoon and evening on Wednesday. With this activity, the main threat initially looks to be some erratic wind gusts (up to 40 mph) with dry air near the surface before the better atmospheric moisture moves in transitioning the threat to more moderate to heavy rain. The cold front will then drop through the area from north to south late Wednesday, turning winds out of the north to northeast. As this occurs, modeled atmospheric soundings suggest the atmosphere will saturate. This would allow more widespread light to moderate precipitation to develop over and near the mountains and foothills late Wednesday into Thursday. As the main trough associated with this weather system slides east Thursday, the chance of precipitation then shifts east and out of the area by late Thursday into early Friday. When all is said and done, the chance of seeing a half an inch (0.50") of liquid precipitation or more is 50 to 75 percent over and near the mountains and foothills in south-central Montana and north-central Wyoming. The chance of seeing a half inch or more of precipitation then decreases away from the foothills with there only being a 10 percent chance by Broadus to Miles City. As mentioned above, the mid-week weather system will bring a brief cooldown back to the area. With this, high temperatures on Thursday are forecast in the 50s and 60s after seeing 60s and 70s Wednesday. This will allow snow levels to start out around 8000 feet before droppingnear 6000 to 6500 feet by Thursday. Subsequently, mainly snow is forecast in the mountains with this event, with rain over the lower elevations. It is not out of the question that some of the immediate foothill locations near 6000 feet in elevation see some snow though (moderate chance). As far as potential snow amounts go in the mountains, the current chance of seeing 6 or more inches is moderate to high, greatest over the northerly slopes of the Absaroka-Beartooth Mountains. Friday into early next week, temperatures look to gradually warm back above normal with mainly northwesterly to westerly flow aloft. With this, additional waves of energy may work through the flow, bringing occasional chances of precipitation. Arends .AVIATION... Patchy fog (20% chance) is possible into the morning hours over portions of the central and eastern valleys with VCFG at KMLS and KSHR. Otherwise, expect mainly VFR conditions to prevail through the period. A weak disturbance moving in from the west will bring isolated showers to western and central areas, including KLVM and KBIL during the afternoon and evening hours. Gusty and erratic winds up to 30 kts are possible with the showers. STP && .PRELIMINARY POINT TEMP/POPS... Tdy Wed Thu Fri Sat Sun Mon ------------------------------------------------------- BIL 065 042/070 044/059 040/071 045/080 050/083 052/087 1/U 13/T 86/W 10/B 00/U 10/U 01/B LVM 060 036/064 037/056 035/069 040/076 044/080 047/082 2/W 25/T 97/W 01/B 00/U 11/U 01/N HDN 066 036/072 042/059 037/073 041/079 046/084 049/087 1/U 12/T 67/W 11/B 00/U 10/U 00/U MLS 064 040/073 044/063 040/070 043/079 048/083 050/086 0/U 11/B 53/W 11/B 00/U 10/U 00/U 4BQ 062 039/072 042/061 039/068 042/077 048/082 051/087 0/U 00/B 25/W 41/B 00/U 10/U 00/U BHK 059 036/073 039/064 037/068 041/076 047/082 049/087 0/U 00/B 35/W 42/W 10/U 10/U 00/U SHR 059 031/066 036/052 032/066 036/075 041/080 043/085 0/U 01/B 39/W 42/W 01/U 11/U 00/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings