Major Changes Next Friday?

I have been watching a major shift for late this week...but have not mentioned it before in this blog...because the models are not dependable out that far. But this morning's runs are continuing this solution...one that would bring much colder air to the Northwest, significant snows in the mountains, and the potential for snow in the lowlands. Specifically, on Friday a configuration close to the classic NW snow pattern develops...high amplitude ridge of high pressure offshore and a sharp upper trough moving southward over us. The models indicate a transition to MUCH colder air with it...which is getting to look more probable. The trick is to get snow in the lowlands...and I wont speculate on this right now. But we all need to watch this pattern...it if is still there on Tuesday...it will be pretty much a sure thing. The TV weathermongers should be ready..particularly my favorite..Jim Foreman of KING TV.
Today the weather is the worst of what has been an exceptional week. A weak front with cooler air is now passing south of us (see satellite picture). The steady rain is south of central Puget Sound and now postfrontal showers are moving in. Because the winds are westerly on the coast, the central Puget Sound region is being rainshadowed (see radar)--with showers in the mountains and on the coast. The freezing level has dropped enough so that the higher passes and elevation have had a few inches of snow. Compare the WSDOT cam images at Stevens pass (with snow) to Snoqualmie pass (rain). Just a thousand feet makes a big difference. A Puget Sound convergence zone will form over or north of Seattle today...so go north or south of it if you want dry weather. A ridge moves in tomorrow for generally dry weather..except for some showers in the mountains.

PS: Several of you have emailed me about the book...it looks like amazon and Barnes and Noble.com have temp sold out (more are being shipped to them). Many local book stores have supplies --except for Northgate B&N. UW bookstore had plenty last week and do online orders--as do many local bookstores.