MISSOULA — Warmer weather quickly returns this week as high pressure rebuilds, but increasing monsoon moisture will bring renewed thunderstorm chances by midweek.
SUNDAY
A cold front swept across western Montana, bringing cooler temperatures to Missoula, the Flathead Valley, Kalispell, Polson, Libby, and surrounding areas. Skies clear this evening as winds gradually diminish after sunset.
MONDAY
High pressure begins rebuilding over the Northern Rockies, leading to mostly sunny skies and a pleasant day across western Montana. Temperatures start a warming trend while light winds and dry conditions dominate from Missoula north through the Flathead Valley and Glacier region.
TUESDAY
The warming trend continues with temperatures climbing above seasonal averages. Morning clouds or a few showers are possible, but attention turns to the afternoon when isolated thunderstorms may develop and expand northward toward the I-90 corridor, including Missoula. Storm coverage will depend on how quickly skies clear after sunrise. The Flathead Valley may remain largely dry, though a stray thunderstorm cannot be ruled out late in the day.
WEDNESDAY
This appears to be the most active day of the week as monsoon moisture spreads across much of western Montana. Showers and thunderstorms become more widespread from Missoula and the Bitterroot Valley north through Kalispell, Whitefish, and the Flathead Valley. Some storms may produce lightning with limited rainfall, raising concerns for new wildfire starts, while others could bring locally beneficial rain.
THURSDAY
Thunderstorm chances continue across much of western Montana as moisture remains in place. Scattered afternoon and evening showers and thunderstorms are possible from the mountains to the valleys. Temperatures remain warmer than normal despite increasing cloud cover.
FRIDAY
A Pacific Northwest trough begins to weaken the ridge, bringing a slight cooldown and increasing afternoon winds. Scattered thunderstorms remain possible, but growing wind concerns may elevate fire weather conditions once again across western Montana.
SATURDAY
The cooler trend continues as the ridge breaks down further. Breezy afternoon winds, seasonable temperatures, and spotty thunderstorm chances are expected across Missoula, the Flathead Valley, and the rest of western Montana. Fire weather concerns may increase depending on rainfall coverage during the preceding days.
