Our large ridge of high pressure is beginning to flatten out putting us in a more zonal weather flow for Friday. According to weather models, the big change comes tonight/Saturday with the incoming trof of low pressure dropping down from the west/northwest. Noted weather expected with the incoming trof include widespread rain, windy conditions, and even a small chance of thunderstorms as the atmosphere becomes conditionally unstable. After the passage of this weather system, the jet stream remains within very close proximity favoring a cool flow from the northwest with some of the instability lingering in the area for Sunday thus suggesting some locations transitioning to showers along with an appearance of a rain-shadow between the lee of the Cascades and the Columbia Basin and some of the nearby lowland and valley locations that starts out Saturday but lingers into Sunday. Forecast temps show the cooling trend with slightly below what would be considered normal high temps after today.
Northcentral Washington can expect increasing clouds throughout the day today but still mild with afternoon high temperatures generally in the lower 70’s. By late tonight/early Saturday morning there is a 70% chance of rain with overnight lows in the mid 50’s.
Saturday’s weather will be wet with a 80% chance of rain throughout the day and much cooler too with afternoon high temperatures in the lower 60’s.
Sunday will be mostly cloudy with a 40% chance of lingering showers, highs in the lower 60’s.
For Monday right through Wednesday of next week, expect occasional precipitation chances, some breeziness and near normal temperatures with highs generally in the lower to mid-60’s. Our best chance of rain next week will be on Tuesday with a 40% chance of precipitation.
By Thursday our weather will stabilize with mostly sunny skies and afternoon high temperatures remaining in the lower to mid-60’s.