Scattered thunderstorms are developing across southern Oregon and southwest Idaho this afternoon, bringing the threat of gusty outflow winds up to 50 mph, small hail, and brief heavy rain, before a prolonged period of dangerous heat builds through the week with temperatures approaching or reaching triple digits by Friday.
Sizzling heat returns into the weekend in Scott Dorval's video forecast
An upper-level disturbance is spinning over southeast Oregon this afternoon, creating a split in conditions across the region. Areas north and east of the disturbance, including the Baker Valley in Oregon and the Cascade and McCall areas in Idaho, have seen clouds and light rain that have kept temperatures down and the atmosphere more stable. However, skies have cleared south of the disturbance and the atmosphere is becoming very unstable across southern Oregon and southwest Idaho. Scattered thunderstorms are developing and will spread north and east through the early evening hours. These storms are expected to produce gusty winds up to 50 mph, small hail, and brief rain. Thunderstorm activity should subside overnight, with about a 20 percent chance of isolated thunderstorms developing again Tuesday afternoon.
Wednesday will bring generally hot and dry weather with southwesterly winds increasing in the afternoon. Thursday will offer a few degrees of cooling with temperatures near normal, thanks to the passage of an upper-level shortwave. Breezy conditions will persist through Thursday with afternoon gusts of 20 to 35 mph across southern Idaho. These breezy conditions, paired with minimum afternoon relative humidity values around 15 percent in the lower elevations, will lead to elevated fire weather concerns for southwest Idaho.
A Four Corners ridge will dominate the rest of the extended period, leading to a week of hot and dry conditions. Valley high temperatures will reach the upper 90s Friday with some locations approaching triple digits. With the area on the periphery of this ridge, even a slight westward shift could allow many lower elevation sites to hit triple digits. Monsoonal moisture could begin working its way around the ridge by Monday, supporting an increasing risk of thunderstorms.
Patchy smoke will be a concern Tuesday morning as a result of ongoing fire activity in the region.
Tonight
A 20 percent chance of showers and thunderstorms before 9pm. Patchy smoke. Mostly clear, with a low around 62. West northwest wind 8 to 13 mph becoming light and variable after midnight.
Tuesday
Patchy smoke before noon. Sunny and hot, with a high near 98. Calm wind becoming west northwest around 6 mph in the afternoon.
Tuesday Night
Partly cloudy, with a low around 64. West southwest wind 6 to 11 mph becoming light and variable after midnight. Winds could gust as high as 21 mph.
Wednesday
Sunny and hot, with a high near 97. Calm wind becoming west northwest 5 to 9 mph in the afternoon. Winds could gust as high as 20 mph.
Wednesday Night
Clear, with a low around 62. Northwest wind 5 to 11 mph, with gusts as high as 23 mph.
Thursday
Sunny and hot, with a high near 93.
Thursday Night
Clear, with a low around 60.
Friday
Sunny and hot, with a high near 100.
Friday Night
Clear, with a low around 64.
Saturday
Sunny and hot, with a high near 99.
Saturday Night
Mostly clear, with a low around 65.
Sunday
Mostly sunny and hot, with a high near 98.
Sunday Night
Partly cloudy, with a low around 66.
Monday
Mostly sunny and hot, with a high near 99.
