174 FXUS65 KMSO 271836 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 1236 PM MDT Fri Jun 27 2025 .DISCUSSION... KEY MESSAGES: - Scattered showers and thunderstorms through this evening across southwest Montana, near the Divide. - Warming and drying trend Sunday into early next week, with temperatures 10-15F above normal. - Shower and thunderstorm activity returns Tuesday, becoming more widespread, especially along and south of I-90. GOES Satellite early this afternoon highlights a blossoming cumulus field across Lemhi County, ID and southwest MT, where the best axis of moisture and instability is present. Radar trends match closely with high resolution model guidance projecting scattered shower and isolated thunderstorm activity near the divide in southwest Montana. This will continue to be the trend through this evening, with gusty outflow winds up to 40 mph being the primary concern with any thunderstorm activity. On Saturday, shower activity will focus across northwest Montana, mainly in Flathead County, as a upper level disturbance moves across southern Alberta. Limited atmospheric instability will limit thunderstorm development, however, an isolated storm or two can`t be ruled out across Glacier Park Saturday afternoon and evening. Breezy westerly winds will develop area wide with the aforementioned disturbance, with gusts of 20-25 mph across valley areas. Ensemble model guidance remains in strong agreement for a ridge of high pressure to settle across the region Sunday into early next week. A warming trend is expected, with temperatures rising 10-15F above normal by Monday next week. Showers and thunderstorms return Tuesday next week, with activity becoming more widespread Wednesday under a south-southwest flow pattern. Ensemble guidance has been consistent the last few days highlighting a surge of subtropical moisture across the Great Basin into the Northern Rockies, with atmospheric moisture climbing 125-150% of normal by Wednesday. This flow pattern will be aided by a ridge of high pressure centered near the Four Corners region and a closed low forming over California, seen within deterministic runs of the 12z GFS/ECMWF. A deeper dive into instability suggests the potential for a few stronger thunderstorms capable of producing heavy rain and small hail given the anomalously high atmospheric moisture. The lack of an organized mid-upper level jet will limit wind shear and the potential for organized long-lived severe convection. && .AVIATION...A growing cumulus field is seen in GOES Satellite imagery this afternoon, with scattered showers forming across southwest Montana near the divide. Model guidance has been trending convection eastward with recent model runs, with storms projected to form along the divide in southwest Montana between 27/2000-2200Z, before quickly shifting eastward. Limited confidence (<20% probability) exists for any storms in the vicinity of KBTM through this evening. Confidence is high for widespread gusts of 15-25kts across most terminal sites through 28/0200Z this evening as an upper level disturbance passes. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. && $$