Area Forecast Discussion
Issued by NWS Billings, MT
Issued by NWS Billings, MT
038 FXUS65 KBYZ 160251 AFDBYZ Area Forecast Discussion National Weather Service Billings MT 851 PM MDT Sat Jun 15 2024 .UPDATE... No more storms are expected this evening across southeast Montana, hence will let the Severe Thunderstorm Watch expire at 9 PM. However, strong, post-frontal winds gusting 40-55 mph will persist across the area for the next few hours. Vertz && .DISCUSSION... Today through Sunday Night... Morning showers and isolated thunderstorms have pushed north and east of the area as of early afternoon. Additional thunderstorms are expected to develop over the mountains this afternoon, spreading east-northeastward through the evening hours as a shortwave lifts through the region. One area of thunderstorms is expected to develop and move off of the western mountains, spreading across northern areas through the afternoon and evening. A second area of convection is progged to develop over the Bighorn Mountains, spreading across northern Wyoming and into southeast MT. MUCAPE of 1000-2500 J/kg and deep layer shear of 30-45kts in place over the area will promote strong to severe thunderstorms, with the greatest threats being strong gusty winds and large hail. The large hail threat is greatest over southeast MT where model soundings show ample CAPE in the Hail Growth Zone. SPC currently has a Marginal risk for severe thunderstorms for areas from Billings west, with a Slight risk for severe thunderstorms for areas north and east. In addition to the thunderstorms, winds will increase in the mountains and adjacent foothills this afternoon, with southwest to west gusts of 30-50 mph. A cold front is expected to move south and east through the region later this afternoon and evening spreading west to northwest winds gusting 20-40 mph. Winds will gradually decrease into the evening hours, remaining breezy over the east into the overnight. If you have outdoor plans in the mountains today, including the foothills, prepare and be aware for windy conditions. Sunday will bring cooler and drier conditions, with breezy westerly winds found across the north (15-25 mph). Precipitation chances begin increasing during the evening and overnight over southeast MT and western areas as a weak shortwave lifts north and east from Wyoming into the Dakotas, and a larger trough approaches from the west. High temperatures will range from the 70s over the west to the lower 90s over the east today, dropping into the middle 60s to lower 70s behind the cold front for Sunday. Low temperatures both tonight and Sunday night will cooler than the last several, with temperatures dropping down into the upper 30s to lower 40s over the west, and 40s to near 50 degrees elsewhere. STP Monday through Saturday... There is a lot of uncertainty in high temperatures Monday as an upper trough drops south into the region. The GFS and Canadian deterministic models bring lower thickness values into values than the ECMWF. The Canadian has the lowest temperatures by bringing the surface high farthest south helping to suppress the deepening low in Wyoming and its southerly winds bringing warm air advection. The ensembles of these models reflect these differences with the Canadian showing a high temperature in the mid 50s, the GEFS showing high 60s and the ECMWF Ens showing high 60s. Tuesday will see temperatures similar to Monday that may be a few degrees warmer. After the passage of the trough, upper heights will rise and put us back into a more downsloped flow raising temperatures throughout the week. Temperatures in the high 70s to low 80s will return by the wnd of the week into the weekend. Monday into Tuesday the upper trough bringing cooler temperatures will also bring precipitation chances to the region. Monday morning will see a deepening low in Wyoming bring winds out of the south with 700mb warm air advection. That will be followed by a cold front passing through Monday night into Tuesday morning switching winds from easterly to more northerly. Models are currently showing our region getting most precipitation on the back side of the low. The trend recently has been to shift the precipitation farther to the north. NBM 48 hour precipitation probabilities for Monday through Tuesday show most of the region having a 50-80% chance for >0.25 inches. Generally the farther north you go the higher the probabilities with lower probabilities around 40% for locations in Sheridan County. Things will start to die down during the day Tuesday with some lingering showers wrapping around the low. Snow levels will get down to around 6,500 ft leading to the chance for light snow on the Beartooth Highway. Most of the Beartooth/Absaroka mountains have a >50% chance of getting over 1 inch of snow. People planning to travel on the Beartooth highway should prepare for the possibility for slippery roads. Wednesday and Thursday will see us enter southwest flow aloft keeping moisture in the region. This will lead to daily shower chances (20-30%) before the possibility of a more significant system for late Thursday through early Saturday. WPC clusters currently dont have much agreement in what this wave will look like. At this time about 75% of models are keeping precipitation amounts under 0.25 inches with the highest amounts for locations east of Billings. Torgerson && .AVIATION... The thunderstorm threat is over for this evening and overnight. However, post-frontal winds will continue gusting 30-45 kts at most terminals over the next few hours, then slowly decrease through the night. Vertz && .PRELIMINARY POINT TEMP/POPS... Sun Mon Tue Wed Thu Fri Sat ----------------------------------------------------------- BIL 049/071 049/065 045/064 044/075 051/081 058/080 058/081 20/B 26/T 73/T 11/U 11/B 23/T 32/T LVM 039/068 041/058 037/061 036/071 043/077 049/078 051/082 30/N 38/T 75/T 12/T 11/B 23/T 22/T HDN 049/073 050/069 043/065 043/076 050/082 057/082 056/082 20/B 36/T 73/W 12/W 12/T 34/T 32/T MLS 051/072 051/066 046/063 044/074 052/081 057/080 057/079 30/N 36/W 94/T 12/T 32/T 44/T 42/T 4BQ 051/073 052/069 047/063 044/074 053/081 058/080 058/079 20/B 34/T 82/W 12/T 32/T 43/T 42/T BHK 049/072 047/064 046/063 041/072 050/078 054/078 054/078 30/N 44/W 93/W 12/W 32/T 44/T 42/T SHR 046/073 045/074 040/062 040/073 047/081 054/080 054/082 10/B 45/T 62/T 22/T 22/T 33/T 32/T && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings