It’s become clear the past two hours the very cold air pouring out of the Gorge is very shallow, more so than we expected. The result? Even most eastern metro locations will NOT be seeing a big ice storm tonight (Whew!) Sub-freezing air is mainly confined to right along the Columbia River and doesn’t extend more than 1-2 miles north and south. You can see that in the latest temperature map, blue temps are below freezing.
Where the temperatures are below freezing, the ice accumulation has been very thick so far:
That’s almost 1/2″ in Troutdale already. If temps were 2-3 degrees colder eastside, this would have been the case for many more of you.
So only the areas right along the Columbia River will see additional icing tonight and of course it’s a big ice storm in the Gorge.
There will be no refreezing of roads tonight and the AM commute should be just fine (ice-wise) everywhere except right in downtown Troutdale and into the Gorge.
For the geeks like me…the Troutdale profiler shows us what’s going on. The cold layer is VERY thin, less than 1,000′ deep over the west entrance to the Gorge! Looks like abourn 50 degrees at the 2,000′ level. Typically in a normal ice/snow event (even for east metro), the cold layer is around 1,500 to 2,000′ thick. I thought it looked a bit strange this morning, but now we know what happened; something to remember for future storms. A cold layer that thin, even with 10-11 millibars easterly flow, will remained confined quite close to the Columbia River. It is still 20-21 at Hood River and The Dalles, which typically would keep the entire east metro below freezing with the east wind. This makes me think the current setup (cold air right along the river) could continue through the night and into midday Wednesday. It’s still going to be a huge ice storm, but only in a very narrow ribbon along the Columbia River, both north and south. I-84 will be close for a day or two I think.
Chief Meteorologist Mark Nelsen