Freezing Rain In The Gorge

November 26, 2010

I’ve been real quiet on the weather blog for a few days…been “under the weather” for the first time in two years.  Somehow I picked up a deathly illness late Tuesday and yesterday was the worst.  Thought I was near the end as I drove the two hours back from Thanksgiving Dinner early, but probably just some sort of severe “man-cold”.  Hopefully I’ll start snapping out of it later today. 

We DID get out of the cold air without a big transition event (that would be today).  So always remember that we can and do occasionaly leave an arctic airmass without a big dramatic event.  Of course that weak warm front brought the flurries and spots of freezing drizzle Wednesday evening, but that was it.  With the transition today, there is plenty of freezing rain and ice pellets in the Gorge.  I have maybe 1/4″ ice here at 1,000′ east of Corbett, at 29 degrees right now.  Some very crunchy snow on the ground.  It’s a very thin layer of cold air in the Gorge and the Columbia Basin too.  I love it when Troutdale is sitting near freezing and the rest of the Metro area is in the 40s…here’s a great map showing the local obs.   Now if we would have had a low pressure area approach from the southwest, then freezing rain would have been widespread across the Metro area.  But models consistently showed the low up to the northwest and lower pressures to the north (4-5 days ago), so that’s why we never had any sort of frozen mix on the 7 day forecast for Thursday and Friday.  The southerly wind up the valley overnight and this morning saved us.  And it sure was a short arctic blast wasn’t it?  Two days with highs around 30, then right back up to 40 yesterday.

The Columbia Basin is totally snow-covered after Monday-Tuesday’s event;  that really made the difference in getting freezing rain through the Gorge this morning and into the far eastside of the Metro area since it’s keeping low-level temps very cool over there.  It’s interesting that looking at the maps I don’t see a big surge of westerly wind to wipe out the cold air in the basin.  In the next 72 hours it’ll stay chilly eastside (at least below about 2,000′).  The inversion with warmer air aloft will go away as cold air overhead moves in later tonight and through the weekend.  But without a good mixing, the snow cover probably won’t melt.  So there will probably be another round of some sort of frozen precipitation in the Gorge when a stronger system approaches on Tuesday.

Westside, we’ll have relatively low snow levels over the weekend…not a ton of precipitation, but snow sticking down around 1,500-2,000′ again.  Similar to what we had before the cold blast Monday P.M.

Chief Meteorologist Mark Nelsen