Updated Friday 5:15 p.m.
Thunderstorms are brewing again over the eastern slopes of the Cascades this evening, and we may have another round of heavy rain leading to flash flooding, mudslides or debris flow near the burn scar areas from the recent wildfires. The strong showers could also include hail, lightning and locally gusty winds. The showers will impact not only Chelan & Wenatchee, but are also focusing on Ellensburg & Yakima as they move to the south. Those traveling across our main east-west passes will have to contend with some tricky driving as the storm cells blow by.
On this side of the mountains, a fairly quiet Friday made for a beautiful August day. Highs hit the middle 70s in Seattle, so after a cool-ish work week, things got back to normal for Puget Sound. Building high pressure over the Eastern Pacific will nudge in our direction on Saturday, and afternoon highs will hover on either side of 80 degrees in Redmond and Puyallup.
On Sunday, another round of showers and thundershowers may pop up over the Cascade crest, so that will be something to keep an eye on due to the potential for more wildfires or flash flooding. Most of the Sound will still max out in the upper 70s, but we'll see a few more clouds floating around for the second half of the weekend.
Thereafter, summer makes a major comeback for the tail end of August. An upper ridge of high pressure will serve to clear us out, and a thermal trough (dry, hot pool of air) will work its way up the west coast from California. That will nudge temperatures into the low to middle 80s in the Central Sound by next Tuesday and Wednesday.
A marine push of air from the Pacific will allow cool, moist ocean air back in by Thursday. Look for morning clouds and afternoon clearing on Thursday, and cool down back into the more typical middle 70s late in the week.
Labor Day Weekend is looming, and it's still looking like it has the potential to get cool & showery. A little late summer cold front approaches Friday night, so we may kick off our Saturday morning with a bit of rain.
Have a great night,
Meteorologists Shannon O'Donnell
The KOMO4 Forecast Team