A shortwave ridge will bring dry and warming conditions through Wednesday, pushing temperatures to around 10 degrees above normal, before a series of weather systems brings a dramatic temperature swing from near 90 degrees on Friday to around 5 degrees below normal by Sunday.
Sunshine much of the week with up and down temps in Scott Dorval's video forecast.
The upper-level pattern will transition to a shortwave ridge over the area, bringing dry and warmer weather through Wednesday. Flow aloft will shift to the southwest on Wednesday as a shortwave trough approaches the Pacific Northwest coast. Current modeling tracks the trough along the Washington-Oregon border Wednesday afternoon, supporting a 20 to 30 percent chance of showers and thunderstorms across southeast Oregon and the west-central Idaho mountains. A lower probability of 5 to 10 percent exists for the Snake River Plain by Wednesday evening. Gusty southwest winds will shift to the northwest behind a cold frontal passage Wednesday afternoon and evening. The shower and storm threat will taper off across southeast Oregon Wednesday night, while a low chance remains in the west-central Idaho mountains.
Temperatures will warm to around 10 degrees above normal by Wednesday, with highs reaching 90 degrees. Cooler temperatures and breezy daytime winds are expected Thursday as the system moves out, before temperatures rebound quickly by 5 to 10 degrees on Friday as southwesterly flow overspreads the region ahead of a deep upper-level trough moving into the Pacific Northwest.
As the weekend progresses, the upper-level low will gradually move across the southern Canadian provinces and the international border. A cold front will pass through eastern Oregon and southwest Idaho on Saturday, increasing shower and thunderstorm chances of 15 to 30 percent across northeast Oregon and the central Idaho mountains. Temperatures will cool several degrees Saturday, with further cooling anticipated Sunday as the trough moves overhead. Gusty winds will persist Sunday but should decrease by Sunday night. Drier and warmer conditions are likely to return Monday as the trough weakens and departs toward the east.
Tonight
Mostly clear, with a low around 49. NW wind 5 to 10 mph becoming calm in the evening.
Tuesday
Sunny, warmer & pleasant, with a high near 84. Light wind.
Tuesday Night
Mostly clear, with a low around 53. Wind becoming calm.
Wednesday
Mostly sunny early, then increasing clouds and hot, with a high near 90. Light morning wind becoming a bit breezy from the NW late in the day.
Wednesday Night
Partly cloudy, with a low around 55. NW wind 10 to 15 mph, with gusts as high as 20 mph then diminishing late.
Thursday
Sunny & pleasant with a high near 80. A little breeze in the afternon
Thursday Night
Clear, with a low around 52.
Friday
Sunny & hotter, with a high near 89.
Friday Night
Mostly clear, with a low around 56.
Saturday
Sunny & warm, with a high near 83.
Saturday Night
Partly cloudy, with a low around 49.
Sunday
Mostly sunny & cooler, with a high near 74.
Sunday Night
Partly cloudy, with a low around 48.
Monday
Sunny & warmer with a high near 84.
