Wildfire smoke from large fires burning across southeast Oregon will continue to blanket the Treasure Valley and central Idaho through the week, degrading air quality and reducing visibility while also moderating afternoon temperatures a few degrees below what they would otherwise be.
Significant smoke creates dangerous air quality at times in Scott Dorval's video forecast
Smoke and Air Quality Impacts for the Treasure Valley
The Treasure Valley will see persistent haze and degraded air quality through at least the end of the week as southwesterly flow aloft continues to transport smoke from several large fires in southeast Oregon into southwest Idaho. Nocturnal and early morning surface inversions, combined with downvalley drainage winds, will concentrate smoke along valley floors overnight and into the morning hours. The Treasure Valley corridor will be particularly impacted during these overnight and early morning periods before mild afternoon mixing offers brief, temporary visibility improvements.
While the smoke will be a nuisance and a health concern, it will also act to block incoming solar radiation, keeping afternoon high temperatures near or slightly below seasonal normals for late July. Temperatures will hover around 96 degrees Tuesday and Wednesday before climbing toward 99 degrees Thursday and 101 degrees Friday as the pattern warms. Saturday looks to be the hottest day of the period with highs near 104 degrees.
Residents with respiratory conditions, the elderly, children, and others sensitive to smoke should limit outdoor activities, especially during the morning hours when smoke concentrations will be highest. Keep windows and doors closed and use air purifiers if available.
Central Idaho Mountains
The central Idaho mountains will also experience widespread smoke impacts through the week under the same southwesterly flow pattern. The smoke will be most persistent in mountain valleys during overnight and early morning hours. Temperatures in the mountains will also be moderated by the smoke cover, running near seasonal normals through midweek before warming toward the end of the week.
Weekend Pattern Change
A dry cold front associated with a British Columbia trough will cross the area Sunday, bringing gusty winds and dropping temperatures to near or slightly below normal Sunday and Monday. This frontal passage will be dry, so no precipitation is expected, but the gusty winds could create additional fire weather concerns. The cold front may also help to temporarily improve smoke conditions as the wind pattern shifts.
Tonight
Widespread smoke, mainly after 5am. Clear, with a low around 62. Northwest wind 5 to 9 mph becoming calm after midnight.
Tuesday
Widespread smoke, mainly before 1pm. Sunny and hot, with a high near 96. Calm wind becoming northwest 5 to 9 mph in the afternoon.
Tuesday Night
Widespread smoke, mainly after 2am. Mostly clear, with a low around 63. Northwest wind 5 to 9 mph becoming light and variable after midnight.
Wednesday
Widespread smoke before 7am, then widespread smoke after noon. Sunny and hot, with a high near 96. Calm wind becoming west northwest 5 to 9 mph in the morning.
Wednesday Night
Widespread smoke. Clear, with a low around 65. Northwest wind 5 to 10 mph becoming light and variable after midnight.
Thursday
Widespread smoke. Sunny and hot, with a high near 99.
Thursday Night
Clear, with a low around 66.
Friday
Sunny and hot, with a high near 101.
Friday Night
Clear, with a low around 67.
Saturday
Sunny and hot, with a high near 104.
Saturday Night
Mostly clear, with a low around 66.
Sunday
Sunny and hot, with a high near 94.
Sunday Night
Clear, with a low around 60.
Monday
Sunny and hot, with a high near 90.
