Well if today didn’t scream INVERSION! I don’t know what did. 30s and 40s in the Valleys; 60s and even 70s in the mountains. Check out the warmest I could find in the Cascades:
It also hit 74 at Abernathy Mtn near Castle Rock and 73 at Marys Peak near Philomath. I added the disco ball for effect…
There was one big surprise today. The east wind was strong enough (at least above the surface) to dry out the lowest 1500′ of the atmosphere all the way down to Salem and up to Woodland. So mostly sunny skies throughout just about the entire Willamette Valley. What a way to screw up a low cloud vs. sun forecast. Much better than the other way around!
What about tomorrow? Since we only have east wind at the surface east of I-205 and dewpoints are around 30 degrees, I think we’re headed towards widespread fog and freezing fog for the Friday morning commute. Models say the easterly flow blasting through the Gorge (gusting 50-60 mph right now) will slow to a trickle by daybreak. Not sure if I believe that since the gradient has been around 6 millibars all day and shows no sign of slackening. But our gloomy Friday forecast is based on the fog developing tonight in the lower elevations and sticking around most of tomorrow. As a result, our forecast is only for 40 at PDX tomorrow. There is also no sign of east wind returning much this weekend, so we clouded up the weekend forecast too. What a pain to figure out fog vs. clouds vs. sun each day…
All models agree on the ridge breaking down Tuesday and Wednesday with a cool and wet trough moving through. Then another colder trough late next week. The ECMWF and GFS have snow down into the hills again about 8-9 days from now (around next Friday-Saturday) with that 2nd trough. 850mb temps are down to about -6. Of course that is still quite a ways away so it could end up either colder or warmer as we get closer. You can see good agreement on the cool trough looking at the 12z ECMWF 500mb ensemble height anomaly for Day10 (a week from Sunday):
That will leave just 5 days to go in January…who knows what happens in those last 5 days, although hints are that ridging returns around that time (2 weeks from now). Note the same map 5 days later shows that idea:
The 18z GFS ensemble chart is similar:
And the 12z GEM:
which never inspires a lot of faith in me anyway.
This January will likely go down as a drier and colder month than normal, probably the coldest January in about 20 years here. I’ve got 2 other thoughts:
1. If it’s the coldest in 20 years, it’ll be without any decent cold weather records. Just consistently cool through just about the whole month.
2. Other than that, not much to write home about this month…move along to February.
Speaking of, since I haven’t shown enough maps, here is Week 3 and Week 4 from last night’s ECMWF monthly run:

Chief Meteorologist Mark Nelsen






24.1° here in Happy Valley. Right on the top of the fog which appears to be about 400-500 feet here. Can’t see below me but can see the top of Mt. Scott in the clear. Don’t forget – no Sellwood Bridge tomorrow!
And here at 2000′ on the plateau above maupin it is 43 and clear as a bell. Stars, no fog, be lucky to freeze tonight. Meanwhile you friends to the west are cold and getting colder. Drove home from potland last night and the slickest spot was between sandy. and zig zag. It was 38 with wet pavement at blue box.
I am near clackamas high school at 350ft and have less than 1/2 mile visibility
Heard 82 degrees at Mary’s Peak? Yesterdays high for the continental US at regular reporting stations was 84 degrees at Orlando Florida. Retiree’s may start heading west.
Yeah but if you look at the sensor the “quality control” message says “caution”. And what’s really weird is there is a snow pack all around the top. So warm, even with a snow pack.
But if want a crazy inversion display, check out Hoodoo ski
weather station. 52 at the top right now, 22 at the lodge below!
http://www.callatg.com/~nsps/weather.htm
Remember, we’re talking very warm surface readings with a snow pack all around. That’s just amazing!
Agreed BD but even if it’s approaching that and is 10 degrees off it’s amazing and other sensors are in the same zone at that height. If this was summer and imagine that stagnate high?
Agreed. I remember skiing at Big Mtn Montana when it was 17 at the bottom and maybe 30 at the top. I thought that was crazy but this puts that to shame.
I-205 and powell 30.6F dropping like a rock and freezing fog building fast, just 3 hrs ago it was 45F
I’ve got a question. My wife, kid an I went to Hopworks on SE Powell and roughly 28th this afternoon. Driving there, we noticed a bunch of what looked like snow between about Hawthorne and Powell. Just a skiff; but enough to coat all north facing surfaces. I know frost can sometimes look like snow, but this just looked too thick to be frost. Wish I took a picture, but there was about 1/4 to 1/2 inch on north-facing sidewalks, lawns, and rooves.
Any ideas? Was it just a ridiculously heavy frost?
I don’t know if this is what you saw, but a lot of bloggers have reported micro-climate snow events. (the area around Intel was mentioned) All of us have lived in a chilled cloud the last two weeks. Droplets of moisture get introduced by HVAC systems and industrial compressors. They seed the cloud we have lived in and cause small amounts of localized snow.
With several days of subfreezing temps (even with clear skies and temps above freezing in the day) frost can continue to build and “thicken”.
Another example, plenty of frozen ponds out there, despite today’s temps in the mid 40s.
We used to get that around here before most of the mills closed down. It was snow. Actually fell from the low clouds as snow flakes during inversions like this. Medford gets it occasionally.
Just not the kind of snow you want your kids to eat!
Thanks all !!
Just got back from Austin Tx beautiful sunny weather actually turned on the air driving back to Dallas it is colder than …. here and all this dry foggy weather will continue for while till we get the 4 months of rain leading to July mark my words. Heading to San Antonio next week to look at homes with the wife getting serious now. The new job is going great!
If you’re tired of the cold/fog, seriously think about making the hour drive up to Government Camp this weekend. Grab a soda at the Govy General Store, sit out front on one of their benches, and enjoy. Sounds silly but it cures!!