Cool and showery weather is in store for Northcentral Washington through the middle of the week as a pair of low pressure systems pivot through the Pacific Northwest. The first system has taken shape as a digging upper level trough off the Washington/Oregon Coast while a moist slow-moving frontal boundary spans much of Western and Central Washington this afternoon with cool and showery weather, mainly west of the Cascades. Meanwhile, plenty of sunshine and mild temperatures stretch from Northcentral Washington into North Idaho today with afternoon high temperatures in the upper 60’s to lower 70’s.
Clouds will increase from the west on Tuesday as the next low pressure system approaches. This second upper trough appears to follow a similar track, digging along the West Coast Tuesday afternoon, swinging inland Tuesday afternoon into Wednesday. This system looks a bit more robust and is bringing a good swath of wetting rains all across Northcentral Washington. Cloudy skies for Tuesday with a 90% chance of steady rain, breezy at times too with afternoon high temperatures in the lower 60’s.
As the weather system crosses Eastern Washington Wednesday afternoon, surface based instability increases with a chance of showers and thunderstorms. The Wenatchee Valley can expect a 40% chance of showers Wednesday and cool temperatures with afternoon highs in the lower to mid-60’s, making it feel more like mid-October than mid-September.
For Thursday and Friday, our weather dries out and temperatures begin to warm up. Expect mostly sunny to sunny skies both days with afternoon high temperatures in the lower to mid-70’s.
A high pressure ridge builds over the Pacific Northwest just in time for the weekend bringing with it drier and warmer temperatures, as well as mostly clear skies. Northcentral Washington can expect high temperatures this weekend in the mid 70’s with overnight lows in the mid 50’s.