FXUS65 KBYZ 222037 AFDBYZ Area Forecast Discussion National Weather Service Billings MT 237 PM MDT Sat Aug 22 2026 .KEY MESSAGES... - Showers and thunderstorms possible through the weekend. A few storms could be strong to severe, especially Sunday afternoon and evening. Localized heavy rainfall a threat as well. - Drier with seasonal temps next week with just an occasional chance of precipitation. && .DISCUSSION... Through Friday... An upper low moving onshore into the Pac NW is causing the ridge axis over the region to slowly shift eastward, bringing an increase in moisture from the south (PWATs 150-200% of normal). A shortwave moving into the region from the southwest will bring scattered showers and thunderstorms to the area during the afternoon and evening, gradually decreasing into the late evening and overnight. Convection will linger into the early morning hours across the far east, where a low level jet is expected to develop. There could be a couple strong storms, with strong winds and small hail. With the high PWATs, any thunderstorm will be capable of producing heavy rainfall. The upper low pushes east along the US/Canada border Sunday into Monday, breaking down the upper ridge. As the low slides east, an associated cold front is expected to push through the area late Sunday. Areas west of Billings could see a period of elevated fire weather concerns on Sunday as pre-frontal conditions bring westerly wind gusts of 15-30 mph, with humidity down near 20 percent. Another round of scattered showers and thunderstorms (30-60% chance) look to spread across the area during the afternoon and evening as well. A few of the thunderstorms could be severe with modest instability (500-1000 J/kg) and shear (deep layer shear around 30 kts). The main threats with the thunderstorms are strong wind gusts of 60+ mph and quarter size hail. Heavy rainfall is possible with the thunderstorms as well. The SPC currently has a marginal to slight risk of severe thunderstorms Sunday afternoon and evening for most of the area. Behind the cold front, Monday will be mostly dry and a few degrees cooler than Sunday. Upper level ridging then builds in by Tuesday, but weak energy and slightly above normal moisture (PWATs around 110-140% of normal) will allow for periodic chances for showers and thunderstorms to continue through the end of the work week. While uncertainty exits, another break down of the upper ridge could occur by late next week. Highs are forecast to range from the 90s most places on Sunday, cooling into the middle to upper 80s Monday and Tuesday. A gradual warming trend is then forecast into the second half of the week with temperatures in the upper 80s to lower 90s. STP .AVIATION... 18z Discussion... Showers are starting to fill in for areas near KBIL/KSHR and westwards. Out east, near KMLS, SE winds are starting to pick up as some gusts top 20 kts. Both of these trends will continue over the coming hours. There will be two rounds of SHRA/TS this evening after 21z and overnight that move from KLVM through KBIL/KSHR, one is more likely than the other at each site and thus a TEMPO and PROB30 were added for each round respectively. Winds with these storms will be erratic with gusts up to 40 kts possible. Rainfall rates my be briefly heavy which may bring VIS down to MVFR, otherwise all sites should stay VFR. Another round of TS is forecast after 18z Sunday. WMR && .PRELIMINARY POINT TEMP/POPS... Sun Mon Tue Wed Thu Fri Sat ----------------------------------------------------------- BIL 067/095 063/088 061/086 061/091 063/093 063/089 061/089 54/T 30/U 00/B 00/B 21/B 20/B 20/B LVM 056/090 050/087 052/086 052/089 052/089 051/087 050/085 76/T 20/U 01/U 11/B 42/T 21/U 21/U HDN 064/097 060/089 056/088 056/093 061/094 060/091 058/090 33/T 40/U 00/U 00/U 12/W 20/B 20/B MLS 068/096 064/087 058/086 057/089 062/093 063/090 060/090 31/U 30/U 00/U 00/U 11/B 20/B 10/B 4BQ 067/095 065/088 059/086 058/089 063/092 063/090 061/090 31/U 30/U 10/U 00/U 11/B 21/B 21/B BHK 062/094 060/088 054/086 051/088 055/091 057/090 055/090 43/T 30/U 00/U 00/U 11/B 32/W 21/B SHR 060/092 058/087 055/084 052/088 056/090 056/088 054/088 33/T 30/U 03/T 12/T 21/B 11/B 11/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings