The Chilly Wind Is Back

January 15, 2009

Snapshot A few tweaks to the forecast tonight.  First, it looks as if a nice cold pool IS developing east of the Cascades, more than I would have expected considering how little snow is on the ground in the Columbia Basin.  A surface high has strengthened in the Columbia Basin with just about 10 millibars easterly gradient from PDX-DLS.  The depth of the cold air east side is almost 3000' now…for example I noticed Middle Mountain (in the MIDDLE of the Hood River Valley), around 2400' is running 8 degrees colder tonight compared to last night.  Corbett at the west end of the Gorge, which is "well-mixed" due to the strong wind, is running 8 degrees colder compared to 24 hours ago as well.  So…I have a feeling high temps will be cooler in at least the eastern 1/2 of the metro area tomorrow.  I went 48 for PDX, but it may only be 44-46.  For sure it'll be windy and chilly east of I-205.  With no change in the upper-level pattern through Monday, I think we'll cool a few degrees through that time.  So forecasts of 50-55 degrees are sure not going to happen.  And for those of you in the windy areas, it's going to be a long period of annoying east wind.

With 10 millibars gradient, the dry air has sure been slow working it's way across the metro area.  Dewpoints in the 20s in Gresham/East Portland are a good sign that eventually we'll get rid of the fog though.  I think it'll be a non-story by midday tomorrow.

If you want warm weather, head up or west.  The Coast should be in the 60-65 degree range the next few days, and some spots in the Cascades made it into the lower 70s today!

Long range, not much to talk about…either ridging or split flow is the story through the end of next week…Mark Nelsen