Area Forecast Discussion
Issued by NWS Billings, MT
Issued by NWS Billings, MT
116 FXUS65 KBYZ 302059 AFDBYZ Area Forecast Discussion National Weather Service Billings MT 259 PM MDT Tue Apr 30 2024 .DISCUSSION... Rest of Today through Thursday Night... The breezy conditions ongoing across the region will subside through the evening hours today. Outside of the wind, isolated to scattered showers have developed over the Beartooth/Absaroka mountains and foothills. This activity will continue through the evening hours before decreasing overnight. Billings could see a light shower with the activity this evening, but the chance remains low at 15 percent. While Billings would see rain, the foothills could see light snow as wet bulb temperatures remain near freezing. Any snow that falls does not look to be impactful. Unsettled weather will continue Wednesday and Thursday across the region with the upper low influence remaining over the region. Wednesday will see a 20-70% chance of precipitation, and Thursday will see a 40-80% chance of precipitation. The best chances each day reside over the mountains where a couple inches of snow is expected (70-80% chance of at least 3 inches / 20-30% chance of at least 8 inches). Over the lower elevations south and west of Billings, the cooler temperatures with drier air near the surface will allow for a rain/snow mix Wednesday through Thursday. While an inch or two of snow on grassy surfaces is possible along the immediate foothills (40-70% chance), snow impacts will be little to none. Liquid precipitation totals over the rest of the lower elevations Wednesday through Thursday are hard to pin down given the spotty nature of this activity, but chances for a total of 0.25 inches or more are low outside of the mountains and foothills. Locally higher amounts are possible under stronger cells though. On that note, there is enough weak instability for a mention of thunder west of Billings and over the mountains Wednesday and mainly east of Billings Thursday. Any activity that gets going will be weak. Breezy conditions will prevail during the day Wednesday and Thursday with 15-30 mph gusts Wednesday, strongest over the western foothills, and 20-35 mph gusts Thursday. Temperatures will remain cooler than normal as well, with highs in the upper 40s and 50s both days. Arends Friday through Tuesday... On Friday, an unstable northwesterly upper flow pattern will be over the Northern Rockies. This pattern will facilitate additional rounds of scattered showers over the area but moisture will be limited (indicated by negative precipitable water anomaly values) so precipitation amounts will also be low, generally a few 0.01" or less. The probability of precipitation (PoP) is 20-70%, greatest in he mountains. Snow levels will be 4000-4300 feet Friday morning, so a light accumulation of snow, one inch or less, is possible mainly in the Red Lodge foothills and in the mountains. The chance of Red Lodge receiving at least one inch of snow is about 25%. Friday night into Saturday, upper air shortwave ridging will move into the region and cause dry weather. In addition, weak surface high pressure will move southeastward from Canada into the northern Plains and contribute to low-level winds turning southeasterly. This low-level southeasterly flow will contribute to warming on Saturday. Saturday night into Monday, models generally agree on an upper trough/low moving east/northeastward somewhere in our region. Models differ, though, on the track of this system, with some taking a more northern track that would give our area less precipitation and more wind, and others taking a more southern track that would give our area more precipitation and less wind. Accordingly, NBM shows increasing PoP values from west to east Saturday night into Sunday night, with PoPs reaching 30-60% Sunday night and again on Monday, greatest in the mountains. NBM shows that the probability of reaching at least 0.25 inches of precipitation from this system ranges from about 25% in southeastern Carbon County to near 60% in the Bighorn Mountains and over 60% in the Crazy and Beartooth/Absaroka Mountains. So, much of the area does have at least a 25% chance of receiving at least 0.25 inches precipitation. Snow should be confined to the mountains above 6000 feet. Monday night into Tuesday, models show large-scale upper air trough over western North America, but differ on the smaller-scale details. Some model solutions show a period of dry weather during this time from shortwave ridging. Others show more disturbances moving through with additional periods of showers. In accord with these solutions, NBM has a 20-40% chance of showers Monday night, then a 20-60% chance of showers on Tuesday, greatest in the mountains. Precipitation in the mountains above 5500 feet will fall as snow. High temperatures will generally be in the 50s Friday, then 60s to lower 70s Saturday, 60s to lower 80s Sunday, and 50s-60s Monday and Tuesday. Saturday through Tuesday, the warmest air will be in southeast MT. RMS && .AVIATION... VFR will prevail during the TAF period. Look for westerly wind gusts of 25-35kts across lower elevations, affecting all TAF sites this afternoon. Winds will decrease by evening. In addition, a weak disturbance from the west will bring scattered rain/snow showers to the area, first to areas west of KMLS and K00F late this afternoon-tonight, then to much of the area on Wednesday. Mountains will be frequently obscured in snow showers. JKL/RMS && .PRELIMINARY POINT TEMP/POPS... Wed Thu Fri Sat Sun Mon Tue ----------------------------------------------------------- BIL 035/053 035/053 033/057 034/067 045/073 046/066 043/066 23/O 26/O 33/W 00/B 13/W 44/W 23/W LVM 030/048 030/051 029/055 031/064 041/065 039/059 037/061 52/S 36/T 33/W 01/B 25/W 44/W 24/W HDN 033/055 033/055 031/057 031/071 043/077 046/069 042/068 13/R 47/R 33/W 10/U 12/W 44/W 32/W MLS 034/055 034/053 034/054 032/066 044/079 048/068 044/066 02/R 35/R 22/W 10/U 01/B 34/W 32/W 4BQ 033/057 034/054 032/054 032/070 045/080 048/068 043/066 02/R 44/T 12/W 10/U 01/B 34/W 32/W BHK 029/055 031/054 031/051 029/064 040/073 044/066 039/063 02/R 46/T 23/W 11/U 02/W 45/W 32/W SHR 029/053 028/052 028/053 029/068 041/076 042/066 038/064 16/T 56/O 35/W 10/U 02/W 44/W 22/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings