SEATTLE — Expect mainly dry weather and cloudy skies Friday morning when you head out for your commute. The air will remain mostly dry, but rain chances increase during the weekend.
An atmospheric river sets up just to our north across Vancouver Island with heavy rain streaming onshore there, clipping the north coast and north interior with heavier rain through the daylight hours Friday. Also, it becomes breezy across the area later in the day but winds could top 40mph around Whidbey Island and the northern waters while wind gusts in the 15-30 mph range are likely elsewhere in the late afternoon and evening Friday.
There is a Wind Advisory for Snohomish County north from Friday afternoon until Saturday morning.
The entire weekend is under a PinPoint Alert Day, especially late Friday into early Saturday morning. The alert is only for the windiest spots to our north and only because it’s our first atmospheric river of the season and trees still have most of their leaves. This is a borderline event that wouldn’t warrant an alert in a couple of months.
Highs will be in the 50s. In the mountains, another few inches of snow could fall before it changes over to all rain Friday night into Saturday.
Saturday will be a blustery and wet day across the area as the weakening atmospheric river sinks south, dousing the whole area with rainfall. It’ll be warmer on Saturday as rain falls, but snow levels will rise. Winds will be in the 15-30mph range Saturday. Similar to Friday, the heaviest rain will be to our north.
The last wave will move across the area on Sunday, with blustery and rainy conditions. The rain will taper off later in the day. Highs will be in the 60s.
By the time rainfall ends on Sunday night, the north coast and Olympics and North Cascades will have had 4-6 inches of rainfall! Rivers coming out of the North Olympics and North Cascades will spike higher but presently are not expected to reach flood stage. In the lowlands, rainfall totals will wind up in the 1-3 inches range across areas north of Everett with 0.50-1.50 inches for the rest of the area, including Puget Sound. For those farther south, expect less rain.
As we enter late October, the weather will be mainly dry with highs in the 50s.