The overall synoptic weather pattern includes an upper low circulation over Oregon and Northern California but indications are the cloud tops are warming, which is also an indication that it is weakening. The very dry Canadian polar air, which has been invading Northcentral Washington, is firmly in control. While we will see light winds today in the Wenatchee Valley, the Okanogan Valley will see strong winds enough to produce dangerous wind chill temperatures this morning and hence the Wind Chill Advisory will remain in effect until 10 am when temperatures recover somewhat and allow the wind chills to be simply very cold rather than dangerous. For the rest of today and into Wednesday the main weather issues around the region will be simply cold temperatures. Under clearing skies today, we will see afternoon high temperatures in the mid 20’s. The coldest temperatures of the season are expected overnight tonight and again overnight Wednesday as skies clear, winds decrease and strong radiational cooling occurs, especially over those areas with existing snow cover. Overnight lows in the single digits above zero are quite possible with lows in the Wenatchee Valley around 12 degrees tonight and 11 degrees tomorrow night.
Thursday will be dry with at least mostly sunny skies under a short-lived upper ridge before conditions deteriorate again on Friday. A complicated and potentially active period is in store later in the week through Saturday as an upper low-pressure system dives south out of British Columbia.
Friday expect cloudy skies with a 40% chance of snow late in the day and 50% chance of snow Friday night, highs Friday in the upper 20’s. Snow is likely on Saturday with an 80% chance and to add to it, wind chills will again be an issue Saturday into Sunday as colder temperatures plunge into the region.
Both Sunday and Monday, we will dry out but remain cold with high temperatures in the mid 20’s and overnight lows in the low teens.