A large weather system well off the coast will sweep a warm front northward and spread valley rain and high mountain snow to Northcentral Washington today. The back edge of the warm front is expected to clear the area overnight tonight and thus precipitation will show a similar decrease overnight. Weather for the Columbia Basin and Wenatchee Valley today, cloudy skies with rain likely but mild with afternoon highs in the lower to mid-40’s.
There will be a short interval between frontal zone passages late Monday night into Tuesday morning however the cold front associated with this same weather system along with some minor smaller scale disturbance moving slightly ahead of it may produce some spotty light shower activity as early as Tuesday afternoon. With this front, the mountains may see up to an additional foot of snow through Thursday morning. Outside of the mountains, precipitation amounts aren`t currently expected to be quite significant with little accumulations expected for the lowlands and none for the Columbia Basin. Tuesday weather will be mostly cloudy with a 30% chance of rain and very mild with afternoon high temperatures flirting with 50 degrees.
For Wednesday and Thursday, a zonal weather-flow pattern from west to east will set up following the cold front and will allow for continuous showers and measurable precipitation for the Cascades and Northcentral Washington with a 30% chance of rain each day with afternoon temperatures in the mid to upper 40’s.
Friday and the upcoming weekend looks to be mainly dry, even for the mountains, as a ridge of high pressure begins to build over the region with partly to mostly cloudy skies and afternoon high temperatures cooling each day from the mid 40’s down to the lower 40’s by Sunday.
This will bring a brief break from the precipitation before the next round of active weather looks to begin by the start of the next work week.