103 FXUS65 KBYZ 200323 AFDBYZ Area Forecast Discussion...Updated National Weather Service Billings MT 923 PM MDT Wed Jun 19 2019 .UPDATE... The severe threat has diminished across the forecast area this evening. The surface trough that was partly responsible for the strong to severe thunderstorms is near the Dakota borders where a line of garden variety thunderstorms currently exists. West of this line, the atmosphere has stabilized and only a few showers and isolated thunderstorms exist. The only update made this evening was to adjust precipitation chances with just a slight chance for most areas with the likely probabilities near the Dakota borders. Hooley && .SHORT TERM...valid for Thu and Fri... An upper trough moving into the region along with a jet max moving overhead and a trough at the surface will generate isolated to scattered thunderstorms across much of the area this afternoon and evening. Thunderstorms will start initially over the southwest mountains, pushing off onto the foothills and plains. Along with modest instability and good deep layer shear, strong to severe thunderstorms are possible across much of the area. Greatest threats are large hail and damaging winds, with heavy rainfall possible as well. The thunderstorms look to exit eastern areas a bit after midnight tonight. Upper trough/low settles in over the region for Thursday and Friday bringing periods of showers and thunderstorms, along with cooler air. A surface trough over southeast Montana and some marginal instability may bring a few strong to severe storms over far southeastern areas on Thursday as well. There remains uncertainty with precipitation amounts Thursday through Friday, although some areas may approach or exceed an inch of precipitation. Temperatures aloft will be cold enough for some snow accumulations over the higher terrain as well, possibly impacting the Beartooth Highway Friday and into the weekend. Will need to monitor for potential highlites. High temperatures are expected to range from the 60s on Thursday, cooling further into the 50s and lower 60s on Friday. Low temperatures in the 40s can be expected through the short term, with a few western valley locations possibly dipping into the 30s Thursday and Friday nights. STP .LONG TERM...valid for Sat...Sun...Mon...Tue...Wed... Ensembles were in very good agreement through the extended period and no large changes were needed to the forecast. An upper low will be lifting NE out of the area on Saturday, bringing good chances for showers and some afternoon thunderstorms to the area. The precipitation will diminish Sat. night. A couple inches of snow are possible on the Beartooth Pass. Highs will be below normal in the 60s on Saturday. Weak upper ridging will move over the area on Sunday with energy in the flow. Scattered showers and a few thunderstorms will occur over the area in this regime and temperatures will be closer to normal. This pattern persists into Tuesday with isolated to scattered showers and storms and a warming trend. Temps are forecast to reach the 80s on Wednesday under advancing SW flow aloft, which will bring more showers and thunderstorms. Arthur && .AVIATION... Expect showers and thunderstorms, mainly E of KMLS to move east into the Dakotas by 09z. More showers and thunderstorms will overspread the area during the afternoon Thursday. Expect generally VFR conditions, however thunderstorms could produce localized MVFR to IFR conditions. Reimer && .PRELIMINARY POINT TEMP/POPS... Thu Fri Sat Sun Mon Tue Wed ----------------------------------------------------------- BIL 048/067 045/063 047/067 049/074 052/076 052/079 055/083 23/T 75/T 35/T 44/T 23/T 22/T 22/T LVM 041/062 040/057 041/062 043/070 046/072 046/075 049/078 15/T 86/T 67/T 55/T 45/T 43/T 34/T HDN 047/068 045/063 046/066 048/073 051/075 051/079 054/084 52/T 76/T 36/T 54/T 23/T 22/T 23/T MLS 049/068 047/062 046/067 049/073 051/075 052/079 055/084 72/T 66/T 34/T 34/T 22/T 11/U 12/T 4BQ 049/068 046/062 045/066 049/071 051/075 052/079 055/084 92/T 65/T 24/T 35/T 22/T 21/U 13/T BHK 048/068 045/063 043/067 046/070 048/073 049/078 053/081 82/T 76/T 24/T 34/T 23/T 12/T 22/T SHR 045/068 041/063 041/065 043/069 046/074 048/079 051/084 63/T 65/T 37/T 55/T 34/T 22/T 23/T && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings