MISSOULA, MT – The National Weather Service in Missoula says portions of north-central Idaho – particularly Clearwater County and Idaho County – as well as west-central Montana and northwest Montana can expect thunderstorms capable of strong winds and heavy rain tomorrow beginning at around 4:00 p.m. and continuing as late as midnight.
The agency says the main threats with the storms will be strong outflow winds of more than 40 miles per hour and heavy rainfall.
“Some high resolution model guidance shows a low end chance (10-20 percent) of a storm capable of producing wind gusts over 60 mph. Potential impacts will be damage to outdoor property, tree damage and potential power outages,” according to NWS-Missoula.
There is a low-end chance (10%-20%) of a storm capable of producing heavy rainfall rates of one inch in 30 minutes, especially in Clearwater and Idaho counties.
“Urban areas could see ponding of water in poor drainage areas if they take a direct hit from a storm. In addition, burn scars and flood prone basins in Idaho county may be susceptible to debris flows,” NWS-Missoula says.
The agency’s Spokane office says Tuesday will bring unsettled weather conditions with periods of showers and thunderstorms in the Lewis-Clark Valley. The first round will arrive tonight between midnight and 7:00 a.m.
“Isolated lightning and brief rainfall are the main impacts with this nocturnal activity,” NWS-Spokane says.
A second round of thunderstorms will arrive tomorrow afternoon and evening between 1:00 p.m. and 8:00 p.m.
A few storms could be strong to severe with gusty outflow winds and hail. Winds up to 60 mph raises concern for isolated tree damage. Storms will also bring a threat for periods of heavy rainfall. At this time, the highest risk for strong storms is across the Idaho Panhandle and along the immediate Washington-Idaho border,” the agency adds.
For the latest forecast updates, visit weather.gov/missoula or weather.gov/spokane.
