A slightly unstable northwest weather flow aloft will prevail over the Inland Northwest through Thursday night with a 20% chance of rain showers today and tonight with highs near 60 degrees. The wave of moisture exits into North Idaho Friday morning as a ridge of high pressure builds in across the Cascades with drier and more stable conditions…at least for one day.
Expect mostly sunny skies on Friday, warmer temperatures with afternoon high temperatures tomorrow in the mid 60’s. As we get to the weekend on Saturday and Saturday night, a deep atmospheric river of moisture will be directed right at the Pacific Northwest. At the same time, a deep trough of low pressure over the Gulf of Alaska will setup this pattern with moisture streaming in from the west-southwest.
In the Wenatchee Valley, there is a 50% chance of off and on showers during the day Saturday dropping to a 20% chance of rain by Saturday night with high temperatures near 60 degrees. Weather models are consistently showing little if any precipitation to the valleys in the lee of the Cascades, Okanogan Valley, Wenatchee Valley and Western Columbia Basin. This is a result of persistent downslope winds over the Cascades.
Sunday and Monday, the upper low moves away from our area bringing mostly sunny skies with just a chance for isolated sprinkles, afternoon high temperatures both days in the upper 50’s. Expect a slow warming trend Monday through Wednesday with occasional showers especially during the afternoon and evening time periods as several weak disturbances sweep over the region in unstable northwest flow. None of these disturbances look noteworthy at this time, as they will be fast moving and bereft of deep moisture.
Weather models are indicating a building upper level ridge of high pressure on Wednesday and into the end of next week with dryer and warmer weather expected with highs Tuesday and Wednesday in the mid 60’s.