The Treasure Valley faces one more stretch of dangerous heat Friday and Saturday, with temperatures reaching 100 degrees both days, before a dry cold front sweeps through Saturday afternoon and evening, dropping temperatures to a much more comfortable 88 degrees Sunday and Monday. Wildfire smoke will continue to be a persistent concern through the weekend and into next week.
100-degree heat gives way to first cooldown of the summer in Scott Dorval's video forecast
Heat Peaks Friday and Saturday
The Treasure Valley will see highs near 100 degrees both Friday and Saturday under mostly sunny skies as southwest flow aloft maintains very warm and dry conditions. Wildfire smoke will moderate temperatures a few degrees below what full solar heating would otherwise produce, but conditions will still be dangerously hot. Low relative humidity values during peak heating hours will make conditions feel even more oppressive. Residents should take precautions to stay cool and hydrated and check on vulnerable neighbors and family members.
Cold Front Arrives Saturday Afternoon
The most significant weather change of the week arrives Saturday afternoon as a dry cold front pushes through the region. Southwest to west winds will increase Saturday morning, turning gusty from the west-northwest Saturday afternoon and evening behind the boundary. Wind gusts of 25 to 35 mph are expected in exposed valley locations and wind-prone corridors. Combined with afternoon relative humidity dropping into the single digits and low teens, the gusty winds will create critical fire weather conditions across the Treasure Valley Saturday afternoon through Saturday night.
Welcome Relief Sunday and Monday
Behind the cold front, temperatures will drop 5 to 10 degrees Sunday, with Treasure Valley highs falling to a much more comfortable 88 degrees. Strong pressure gradients behind the front will maintain gusty northwest winds through Sunday afternoon and evening, with gusts of 30 to 40 mph possible along the Snake River Plain. Temperatures will remain near 88 degrees Monday before a gradual warming trend returns temperatures to the mid-90s by Wednesday and Thursday.
Smoke and Air Quality Impacts
Wildfire smoke from large fires across Oregon will continue to impact the Treasure Valley through the weekend and into next week. The cold frontal passage Saturday afternoon may bring some near-surface improvement in smoke concentrations as it promotes deeper boundary layer mixing. However, westerly winds behind the front will continue to transport smoke from eastern Oregon fires across western Idaho, keeping degraded air quality in place through the end of the weekend and likely through the end of next week. Smoke will be most concentrated overnight and during the early morning hours before afternoon mixing provides brief improvements.
Residents with respiratory conditions, the elderly, children, and others sensitive to smoke should limit outdoor activities during the morning hours and keep windows and doors closed.
Central Idaho Mountains
The central Idaho mountains will also experience smoke impacts through the weekend and into next week. The cold front Saturday afternoon will bring gusty winds and critical fire weather conditions to the mountains as well, with the tight pressure gradient keeping breezy conditions going through Sunday. Temperatures in the mountains will also moderate Sunday and Monday behind the front before warming again midweek.
Tonight
Patchy smoke. Mostly clear, with a low around 64. Light wind.
Friday
Areas of smoke. Sunny and hot, with a high near 100. Light wind
Friday Night
Patchy smoke before 1am, then patchy smoke after 3am. Mostly clear, with a low around 67.Light wind
Saturday
Patchy smoke. Sunny and hot, with a high near 100. Light wind becoming breezy later in the day from the NW.
Saturday Night
Areas of smoke. Mostly clear, with a low around 63. Northwest wind 10-15 mph, with gusts as high as 23 mph early then diminishing
Sunday
Sunny & cooler, with a high near 88.
Sunday Night
Clear, with a low around 56.
Monday
Sunny & comfortable, with a high near 88.
Monday Night
Clear, with a low around 55.
Tuesday
Sunny and hot, with a high near 93.
Tuesday Night
Clear, with a low around 60.
Wednesday
Sunny and hotter, with a high near 97.
Wednesday Night
Clear, with a low around 62.
Thursday
Sunny and hotter, with a high near 96.
