We are slowly transitioning out of the cold arctic air mass this morning. Temperature stayed in the mid-upper 20s overnight in the metro area due to the cloud cover; practically tropical compared to the previous 4 mornings!
We escaped without major issues for the morning commute; models did a great job showing extremely light (or no) precipitation overnight in our area. Looks like just about no one had more than 1/2″ of snow and just a few pockets of freezing rain. If we don’t get any freezing rain before noon, we are probably clear for this event. Remember from past events that for freezing rain to “stick” and cause issues on roads, the temperature needs to be 30 or below, especially during the day since even on a cloudy day we get some energy from the sun to warm road surfaces. At 10am, ODOT sensors on Highway 30 around Sauvie Island, I-205 at Division, and a couple of others show road surface temps now at freezing or above. We should top out slightly above freezing today, then with some spots of clearing drop down below freezing again tonight.
As a result, at this point the afternoon commute looks even a bit better than this morning.
There is a chance we get a spot or two of freezing drizzle or a flurry tonight, but most of the energy for lifting the cloud layer to produce precipitation will be gone.
We did have interesting and unusual weather in the Columbia River Gorge the past 24 hours…it was WARMER than here in the metro area. I see The Dalles made it up to 38 in the middle of the night, same thing at Hood River. Wait a minute…isn’t it always colder in the Gorge at the end of a cold spell? Not this time, we had weak westerly flow through the Gorge, and some warmer air from above mixed down with those west winds. That will come to an abrupt end tonight when surface high pressure strengthens on the east side of the state. Thus it will be a significantly colder day in the central/eastern end of the Columbia River Gorge tomorrow and the gusty east wind will return. Think of it as the colder east side air “sloshing” back into the Gorge overnight.
So what happens beyond tonight? A very slow weather pattern with a few weak systems. One on Thursday and another possibly later in the weekend. I don’t see significant rain, or mountain snow, until the middle/latter part of NEXT week. Our drier than average weather pattern we’ve seen since October continues with upper-level ridging nearby. A very persistent pattern this cool season so far…
Will precipitation start as snow or freezing rain Thursday? Very unlikely for most of us.
- No strong east wind, or even much at all, to supply a reinforcing shot of cold air out of the Gorge. We will moderate temps quickly with a southerly wind above the surface. By Thursday afternoon the actual snow level is over 4,000′.
- Atmosphere overhead would only support freezing rain, not snow. That’s pretty clear on forecast soundings.
- Precipitation arrival appears to be at midday. Unless temps are 30 or below late morning to midday Thursday, freezing rain won’t be able to freeze to road surfaces. If the system were to rush in at 7am I could see pockets of freezing rain Thursday morning after a mainly clear night Wednesday night.
I could see a better chance for a few pockets of freezing rain in the Gorge…maybe. This is also going to be a weak system without much wind or precipitation.
Chief Meteorologist Mark Nelsen