Satellite imagery this morning indicates a moist northwesterly weather flow over the forecast area under the shoulder of a broad Eastern Pacific ridge of high pressure. The key feature is the long and deep plume of subtropical moisture now hosing the British Columbia Coast. All the latest weather models are in good agreement and consistent over previous runs in slumping this atmospheric river of moisture southward and directing it into the northwestern U.S. coast today leading to another on-set of light to moderate stratiform valley rain and mountain snow during the afternoon over most of the forecast area. Cloudy skies in our Monday forecast with 60% chance of afternoon and evening rain with high temperatures in the lower 50’s.
Another issue to keep an eye on will be potential for windy conditions Tuesday across the Columbia Basin but particularly in the Cascades as a trailing mid-level cold front settles into Northcentral Washington Tuesday morning as the moisture feed pushes south of the Pacific Northwest. Wenatchee Valley wind speeds tomorrow will be around 15-25 mph with gusts to 32 mph. A large area of high pressure in the Pacific will also allow some compressional warming with high temperatures on Tuesday under mostly sunny skies all the way up into the lower to mid-60’s. T
hat large area of high pressure over the eastern Pacific will shift in over the Inland Northwest Wednesday leaving us under a quiet weather pattern right through the rest of the workweek.
Expect mostly sunny skies Wednesday through Friday with mild high temperatures in the upper 50’s to lower 60’s with overnight lows in the lower 40’s.