Discussion
Scattered strong to severe thunderstorms this afternoon and evening, with strong winds, large hail, and heavy rain.
Another round of scattered strong to severe storms possible Friday afternoon and evening
Trending drier and breezy this weekend, thunderstorms returning by Tuesday next week
The concern for strong to severe thunderstorms remains this afternoon and evening across much of western Montana and north central Idaho. High resolution models show two main areas of thunderstorms with slightly different timing and threats.
Thunderstorms in southwest and west-central Montana will likely form on the earlier side, as early as 1pm, and linger through roughly 10pm. These storms will largely form on the terrain initially but may spread into valley locations towards early evening. The bigger threat with these storms will be large hail (quarter sized or bigger) and heavy rainfall. Severe wind gusts can't be completely ruled out, but lack of strong forcing aloft and overall slower storm motions favors gusts more in the 40 to 50 mph range.
Thunderstorms in northwest Montana and north central Idaho will likely form later in the evening and continue into the overnight timeframe, generally 7pm and 1am MDT. These storms will be driven by better forcing aloft, with lightning already occurring upstream in eastern Washington/Oregon. These storms may pose more of a wind threat with the potential for upstream convection to form into more of a line as it moves into northwest Montana, meaning wind threats could be more widespread. Wind gusts 58 mph or higher are possible with the stronger storms. Heavy rain and hail will also be a concern.