337 FXUS65 KBYZ 270132 AFDBYZ Area Forecast Discussion National Weather Service Billings MT 732 PM MDT Sat Jul 26 2025 .KEY MESSAGES... - Isolated to Scattered thunderstorms this evening have the potential to produce strong/erratic wind gusts. - Daily chance of showers and thunderstorms Sunday through much of next week. The threat of heavy rainfall increases. The best potential for more widespread precipitation is Tuesday through Thursday. - Near normal temperatures (upper 80s to mid 90s) through the weekend turning slightly cooler than normal next week. && .730pm UPDATE... WW545 for Musselshell and Golden Valley counties has benn canceled as all of the storms have moved out of the area or weakened. WW546 continues for Fallon and Carter counties. WMR && Through Sunday Night... .DISCUSSION... CAMs continue to point to SE corner of Montana as most likely to see strong to severe thunderstorms this afternoon/evening. Satellite does confirm weak perturbation tracking northward from Wyoming toward this area where ingredients include shear values progged to reach 35-40 kts and MUCAPE greater than 2500 J/kg all within a thermal ridge at 700 mb. So window in Powder River/Carter County for severe weather is from 430-730 PM with gusts 60-70 mph and hail a possibility. Elsewhere, PWATs are in normal seasonal range with some downslope in mixed environments. Weak perturbations also tracking over our west and central areas should result in typical isolated to scattered convection coming off mountains and moving northeast. Given inverted-v soundings and weak forcing, erratic wind gusts 40-50 mph are most likely impacts with any of these storms...but isolated gusts 50-60 mph are possible. Convection will exit through the evening and this will be followed by another dry period late tonight thru Sunday morning. It still appears best forcing will clip our NW zones tomorrow. S expect less coverage Sunday afternoon and evening with generally garden variety t-storms across our west and north sections of CWA. One thing to note is that pwats Sunday should be pretty similar to today. Temperatures Sunday will be slightly cooler than todays and very close to normal. Look for highs in the mid 80s to lower 90s. BT Monday through Friday... For the long term, continuous disturbances under southwest flow as well as southeast flow at the low levels will allow for daily chances (30-60%) of showers and thunderstorms. This pattern will lead to increased atmospheric moisture (pwats ~ 1-1.3 inches) and thus increased instability which will allow for these daily chances of showers and thunderstorms. Into Tuesday, southeast low level winds will wrap around into the foothills across south central MT. With this, the ensembles are showing anomalously high instability levels for this time of year, especially for this area (sfc CAPE values around 1200-1600 J/kg). With the lack of shear in this pattern, storms will be slow moving and pose a risk for heavy rain under any strong thunderstorms. Ensembles aren`t quite in agreement on the placement of the heaviest rainfall, so make sure to watch the forecast as the time approaches. High temperatures will be in the upper 70s and 80s for the period, with the coolest days occuring mid week. TS && .AVIATION... Expect isold/sct showers/thunderstorms through evening. Storms will have the potential to produce strong and erratic winds (localized gusts of 45+ knots), and perhaps brief MVFR conditions. KRPX- KMLS-KBHK at risk for impacts this evening (30% chance). Otherwise, VFR will prevail across the region, though slant range visibility may be reduced at times due to wildfire smoke aloft. BT && .PRELIMINARY POINT TEMP/POPS... Sun Mon Tue Wed Thu Fri Sat ----------------------------------------------------------- BIL 062/092 060/085 061/081 061/082 061/086 061/088 061/088 31/U 11/U 23/T 44/T 53/T 33/T 32/T LVM 052/089 051/085 054/081 054/081 054/083 053/086 052/086 22/T 23/T 34/T 45/T 45/T 44/T 33/T HDN 059/092 059/088 060/083 060/084 060/087 060/089 059/089 30/U 11/U 23/T 44/T 53/T 32/T 32/T MLS 065/092 064/085 062/081 061/081 062/083 062/087 062/089 31/U 23/T 33/T 43/T 53/T 32/T 32/T 4BQ 062/092 064/090 063/081 061/080 062/081 063/084 062/087 40/U 11/U 23/T 64/T 53/T 32/T 32/T BHK 060/091 061/082 057/079 057/078 057/079 058/081 058/084 41/U 13/T 43/T 43/T 43/T 32/T 32/T SHR 054/091 055/088 057/082 056/082 056/082 057/087 056/087 30/U 10/U 13/T 56/T 54/T 33/T 22/T && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...Severe Thunderstorm Watch 546 in effect until 2 AM MDT Sunday FOR ZONES 33-37. WY...None. && $$ weather.gov/billings