An upper level weather system is clearly visible on satellite just off the Washington coast this morning. Latest weather models are in good agreement and consistent in ejecting this feature through the Northwestern U.S. over the next 48 hours. Cold air aloft combined with afternoon surface heating will destabilize the atmosphere and promote the development of more scattered rain/snow and graupel showers and a small chance of an occasional lightning strike or two over much of the forecast area this afternoon and early evening. Northcentral Washington can expect mostly cloudy skies and a 40% chance of rain by afternoon with high temperatures today in the mid 50’s.
On Wednesday, some drier air from Canada begins to bleed into the region through the Okanogan Valley bringing mostly sunny skies with temperatures about normal for this time of year into the mid 50’s.
For Thursday, a dry but seasonably cool break period will envelop the region as the upper level trough moves off to the east allowing a follow-on short-wave ridge of high pressure to build over the area.
On Friday through Monday, the polar storm track looks like it will remain over or nearby to the north of the forecast area through the weekend which will promote continued unsettled conditions with frequent bouts of showers mainly concentrated over the orographically favorable high terrain surrounding the Columbia Basin and Wenatchee Valley. We will also see a slow warming trend through the upcoming weekend.
Mostly cloudy for Friday with afternoon highs in the mid to upper 50’s. Mostly cloudy weather conditions for Saturday with a 30% chance of late-afternoon showers with highs in the upper 50’s. Our chance for rain goes up to 50% on Sunday with afternoon highs near 60 degrees. Monday looks wet too with a 40% chance of showers and afternoon high pressure into the lower 60’s.