Tuesday’s frosty morning gives way to sunny afternoon in Portland; high 47

High pressure lingering over the Pacific Northwest will offer up another sunny dry day and widespread morning frost Tuesday.

Many metro areas were reporting temps well below freezing early Tuesday with even some readings in the low 20s in Forest Grove and the Yamhill Valley area.

Portlanders should see widespread frosty conditions through about 9 a.m., and then clear, sunny skies again through Tuesday evening. The high will be near 47 degrees.

The National Weather Service and the Department of Environmental Quality have issued an air quality advisory in the southern and central Willamette Valley.

A subsidence inversion and weak winds have limited air mixing at the surface and can trap pollution and smoke particles. Those with breathing problems or health issues effected by pollution should limit time outdoors and seek the advice of a professional if they have breathing complications. The advisory is expected to end on Thursday when rain moves back into the region.

Advisory may remain in place until Thursday.NOAA/Portland

The Portland/Vancouver areas will see another clear day Wednesday after morning frost. The high will be near 46. This will be the final dry day for a while. If you’re still working on those outdoor Christmas lights, Wednesday will give you time to get it done.

A cold front moving south from the Gulf of Alaska will move into the region early Thursday morning. Snow levels will still be low, and the Cascade Mountain passes may see a bit of snow as the weak system moves through. This is not expected to be a big rain maker. The weather service is seeing only a 10-20% chance of exceeding 0.50 inches of rainfall in the valleys. The Coast Range and Cascades see a better chance at about 50-70%.

Portland will see rain mainly after about 10 a.m. The high will only be 44 degrees, so make sure you bundle up.

Friday will be another wet day with rain likely all day and breezy winds. The high will be near 46 degrees.

Friday will also be a snowy day across the Cascades. Mountain pass roads could see light accumulations, but no advisories are planned at this time.

The extended forecast calls for more light snow in the mountains through Saturday, and rain in the valleys. A warm front is set to arrive on Sunday which should raise the snow level and continue rain showers in the valleys.

The atmosphere has been dry and stable with light winds for most of eastern Washington and eastern Oregon. Fog and stratus continue, and Air Stagnation Advisories are in effect. #wawx #orwx pic.twitter.com/FIgRxoGhkn

— NWS Pendleton November 28, 2023