Weather 9-10-20

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The upper level ridge continues to sit over the Pacific Northwest, keeping skies free of any clouds. However, lingering smoke and haze from wildfires will continue to impact Central Washington and may impact how high our temperatures get over the next few days. Air quality will remain an issue as light winds will allow smoke to build around the eastern slopes of the Cascades and the Eastern Columbia Basin.

Weather today and tomorrow will be 3 to 7 degrees warmer than yesterday with highs in the upper 80s to around 90 degrees. Overnight lows will be in the 50s for most of the region, but our cooler, low-lying valleys will dip into the low to mid 40s.

On Friday, the ridge flattens and begins to shift southeastward. As a result, the highly anticipated onshore flow will return and winds will shift to the southwest. This is good news for fire-fighting efforts, especially for the raging fires west of the Cascades. On the other hand, a return to an onshore flow pattern means that the smoke from the aforementioned fires will be transported eastward. The Inland Northwest will begin see an increase in widespread haze and smoke later tonight and it will most likely stick around for a few days. Under hazy skies Friday, expect afternoon high temperatures to approach 90 degrees.

Could Saturday and Sunday be the last of the hot days of the season? Under sunny, hazy skies, daytime temperatures will be around 90 both days, but smoke is the wild card here. The flow will be onshore, and this could bring smoke from the Cascade wildfires into our forecast area. This could knock a few degrees off of the forecast high temperatures. It`s too far in the future to predict if there could be any air quality impacts.

Changes then occur to the overall weather pattern on Monday. A cut off low off the California coast is picked up by the jet stream and is pushed close to the Pacific Northwest. Expect a marine push of air on Monday knocking about 10 degrees off the temperatures with afternoon highs in the lower to mid-80’s.

By Monday night, the Pacific weather system will eject waves of moisture into Northcentral Washington bringing the Columbia Basin and Wenatchee Valley around a 30% chance of rain. The chance of rain goes up to 40% on Tuesday with afternoon highs in the lower 80’s. There is still a 30% chance for scattered showers Tuesday night and a 20% chance on Monday with high temperatures in the lower 80’s.