Ready for a glorious, sunny weekend, Boise? It’s about to get unseasonably warm
Just when you thought summer weather was over and started putting away those lightweight clothes, a large upper-level ridge is arriving to put Boiseans back in their shorts and T-shirts this weekend.
The National Weather Service in Boise forecasts high temperatures to reach 81 over the weekend, the first time temps have hit the 80-degree mark since Sept. 26.
“As that high slowly moves east across the area, that warm dome of air will just be sitting right on top of us,” Weather Service meteorologist Chuck Redman told the Idaho Statesman on Thursday.
Why is it warming up this weekend?
The high-pressure system — typically associated with clear skies and warmer weather — was already parked over the Gem State as of Thursday afternoon.
The system pushed the jet stream as far north as Canada, allowing warmer air from the south to filter northward. The jet stream is a band of strong winds in the upper atmosphere that shifts north and south, pushing cooler and warmer air north or south and allowing the opposite to move in behind it.
With the high-pressure system in place, no cold air from the north can penetrate Idaho, but warm air from the south can drift our way.
“That southwest flow will help with the warming conditions,” Redman said. “The jet stream is moving up well into central Canada over the next several days and will start coming back down closer to our latitude (on) Monday.”
The Weather Service is calling for high temperatures in the mid-70s on Friday, 79 on Saturday, and 81 on Sunday and Monday. All four days are expected to be clear or mostly clear, with bright sunshine.
Cooling down next week
As soon as the high-pressure system moves out of the area, the jet stream will dip to the south and mark a pretty big change. It won’t necessarily get cold, but things will return to normal for early October. The high is expected to be 61 on Wednesday, according to the National Weather Service. The typical high temp this time of year is in the mid-60s.
There could be some snow in the Boise Mountains by midweek, as overnight lows dip into the 40s and 30s, and some precipitation moves into the area. Redman expects at least a dusting of snow could occur through the week at elevations higher than 7,500 feet. For reference, Boise sits at about 2,700 feet.
Clear skies could come just in time for the annular solar eclipse visible from Boise on the morning of Saturday, Oct. 14.
“By Friday of next week it’s trying to build another (high-level) ridge over us,” Redman said. “We could potentially see temperatures coming back up by next weekend.”
