BUTTE – Another wonderful weather day for SW Montana. Conditions have not changed at all over the last 24 hours with a weak NW flow aloft and a strong High-pressure ridge parked along the Pacific NW coast.
Temperatures under that blocking ridge are jumping up into the mid to upper 90s for Portland, OR today and again tomorrow. That extreme heat is not expected to move over Montana although temperatures will be warming up through the weekend into the upper 70s to mid-80s.
The next weather maker will be a weak disturbance undercutting the ridge pattern and will produce late afternoon to early evening thunderstorms Wednesday through Friday. At this time most storms will your typical garden variety with several storms on the weak side and maybe 1 or 2 slightly strong thunderstorms. Severe thunderstorms are not expected at this time but that could change.
Most afternoon thunderstorms Wednesday through Friday will produce brief periods of moderate rainfall, frequent and deadly lightning, strong outflow wind gusts and small hail.
City by City Forecast:
BOZEMAN: LOW: 44°; HIGH WEDNESDAY: 78°. Clearing after sunset and cooler by Wednesday morning. Wednesday should be a warmer day starting off with mostly sunny skies and light winds. Late afternoon look for building clouds and a slight chance for a few thunderstorms.
BUTTE: LOW: 43°; HIGH WEDNESDAY: 78°. Partly cloudy to mostly clear tonight for Butte. Mostly sunny and warmer Wednesday with a slight chance for a late afternoon to early evening thunderstorms.
DILLON: LOW: 44°; HIGH WEDNESDAY: 78°. Mostly clear and cool tonight for Dillon. Wednesday will begin with mostly sunny skies but building afternoon thunderstorms are possible and a few could produce brief heavy rain, small hail, frequent lightning, and strong surface winds.
WEST YELLOWSTONE: LOW: 34°; HIGH WEDNESDAY: 70°. Clear and frosty overnight for West Yellowstone. Mostly sunny Wednesday morning but by late afternoon mostly cloudy with a few scattered thunderstorms that could linger into the early evening hours.