Monday, March 2, 2009
Cold and Snow?
It is March 3, and the weather maps for later this week and the weekend, are a real eye-opener--some the coldest air I have seen this late in the season for an extended period of time. And yes, there are snow chances for the lowlands. But keep in mind that we are working against the clock. Significant lowland snow after the first week of March is increasingly unlikely--although we did get an inch last April (the frigid spring from hell--or I should say the arctic).
During the next day or so, we will be in the typical spring shower regime. Right now a band is heading towards us (see satellite pic) and should get to Washington overnight (the precipitation from it is visible in the Portland radar).
But that is not the fun part.
A major upper-level ridge develops over the eastern Pacific on Wednesday and a trough moves southward over us on Thursday (see map). Such a flow pattern will bring colder air, certain snow in the mountains, and perhaps in some high elevations...but it is not ideal for much lowland snow..the trough is too far inland. But this pattern doesn't go away and another trough moves in on Sunday...and is much more threatening..colder and and more favorable trough location with greater upward motions. The WRF model in fact puts down some lowland snow...but this is so far out, I would not get too excited yet (image). My rule of thumb is I don't get psyched about snow until we are within 96hr of the event. But I would get those salt trucks ready. And the cold air holds in. Just amazing.
PS: the Northwest weather workshop will be on March 20-21st..the major annual meeting of local meteorologists and hard-core weather enthusiasts. If you want more info or to register, check out:
Posted by Cliff Mass at 9:55 PM