A brief but significant warmup will push temperatures back to 90 degrees on Friday before a series of weather systems brings near to below-normal temperatures, gusty winds, and a potentially significant precipitation event early next week.
Hotter Friday but check out the changes in our weekend in Scott Dorval's video forecast.
Zonal flow continues today as a trough off the British Columbia coast moves south. As the trough moves south, the flow aloft shifts to the southwest, allowing for around 10 degrees of warming on Friday afternoon. This trough will move into Washington on Friday afternoon, bringing a dry cold front through eastern Oregon on Friday evening. Gusty winds up to 35 to 45 mph are possible Friday evening along the Interstate 84 corridor from Baker City to Ontario, Oregon as the cold front moves through.
The trough will continue moving across Washington on Saturday, with mostly cloudy skies. Showers and thunderstorms will generally be confined to areas north and east of the region, across eastern Idaho and the central Idaho panhandle. Dry and breezy conditions are expected Saturday afternoon, with temperatures near normal or around 10 to 15 degrees cooler than Friday.
Showers in central Idaho will move east Sunday as an upper-level trough moves into western Montana. As the trough moves out, gusty winds will impact much of Idaho, especially in south-central Idaho and parts of the Snake River Plain between Boise and Twin Falls, where gusts are forecast to reach 25 to 35 mph. Afternoon temperatures behind the trough will be about 5 degrees below normal.
Temperatures will not have much time to rise following the cool and breezy weekend, as weather models are in broad consensus bringing a strong trough through Idaho early next week. Precipitation will begin moving into southeast Oregon Monday evening, spreading over all of southeast Oregon and southwest Idaho on Tuesday, then southwest and central Idaho as it exits eastward Wednesday and Thursday. These areas will see a 20 to 40 percent chance of precipitation, except on Tuesday where the core of the low will bring a 50 to 70 percent chance of precipitation over the mountains.
Rainfall through the entire event is forecast to total up to 0.1 inches in lower elevations and up to 0.75 inches in the mountains. Thunderstorms are possible each day, especially Tuesday, and could bring much higher local rainfall amounts. The cooler surface temperatures will bring some snow to summits and ridgelines. Wind gusts of 15 to 30 mph are expected each afternoon during the low's passage.
Tonight
Mostly clear, with a low around 53. NW wind 5-10 mph becoming calm in the evening.
Friday
Sunny and hot, with a high near 90. Light wind.
Friday Night
Partly cloudy, with a low around 54. Light wind with a breeze developing overnight.
Saturday
Partly sunny & cooler, with a high near 76. Northwest wind 5-15 mph.
Saturday Night
Partly cloudy, with a low around 46. North northwest wind 10 to 13 mph.
Sunday
Sunny & cool, with a high near 72.
Sunday Night
Mostly clear, with a low around 48.
Monday
Increasing clouds with a slight chance of evening showers. Warmer, with a high near 77.
Monday Night
A 20 percent chance of showers after midnight. Mostly cloudy, with a low around 51.
Tuesday
Scattered showers & storms, with a high near 75. Chance of precipitation is 50%.
Tuesday Night
A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 49.
Wednesday
Scattered showers & cool, with a high near 71.
Wednesday Night
A 20 percent chance of showers. Partly cloudy, with a low around 46.
Thursday
Sunny, with a high near 73.
