The last few rain and snow showers moved out this morning/early afternoon. Our next feature will bring us a long stretch of dry weather, but will have us watching the air quality closely.
A large ridge has moved in just off shore and will not move much this next week. While that does mean some clearer and drier conditions, it will also mean cold mornings and some fog. The reason for the cold air is partially due to the fact the clockwise motion around the high is pulling cooler air from the north down into the area. However, being that mid-level temps are high on the models, that is not the primary reason. What is really going to help morning temps drop, will be clear skies. With no cloud cover to hold the air close to the ground, many of us will wake up to upper 20’s and low 30’s for the rest of the work week and weekend.
Why the fog? A few reasons, one being that we live beside an ocean. However, when we see temps drop this low, it is easier for us to meet the dewpoint temps. With overnight inversions in place, not only will we form the fog, we’ll also keep it low for the duration of most mornings this week.
Another concern with this high pressure will be stagnant air. The winds will be light, we’ll have a cap (inversion) over the area well into the day, and the air will not mix out easily. Add to that the fact that cold overnight lows will mean more people cranking up the wood stoves and fireplaces, we could see air quality start to dip. There is currently a Stagnant Air Advisory for the Umpqua Basin including the cities of Sutherlin and Roseburg. That advisory has been issued for 4 AM Thursday to 4 AM Tuesday. While there is not a current advisory for the Willamette Valley, we’ll be watching LRAPA’s AQI to see if our quality dips as well. Right now it looks like the poorest air quality will be towards the end of the weekend or beginning of the next week.
With the cold temps, some of the local warming centers are opening up. Here’s a list of some of them: http://kezi.com/news/local/232146
— Meteorologist, Megan Taylor