Sunday, January 25, 2009
Sunday Morning Update
The air above us is now cold enough for snow...and there are a few light flurries going on now as the final bands of showers from the passing weather disturbance move through (see figure). Last night some locations received 1/4 to 1/2 inch (a few slightly more)..particularly at higher locations in the North Sound. And as I mentioned last night, the model's definitely underplayed it. Cooler, drier air is now moving through the Fraser River Valley. Take a look at the surface chart (attached)..strong NE winds (20 knots sustained) at Bellingham Airport..with a temp of 27 and a very dry dewpoint of 2F! If you want to get a better idea of the winds go to the Ferry Weather Web page (http://i90.atmos.washington.edu/ferry/Ferryjs/mainframe1.htm) and click on the San Juan Island close up map...winds of 25-30 kts are found at some locations.
The sky has opened up in Bellingham and clearing will move southward slowly during the day. Light snow is still falling over portions of central and southern Puget Sound and will do so until midafternoon. Expect temps to drop into the 20s and teens Monday AM--so protect those vulnerable plants.
Several of you have mentioned the issue of snow on Tuesday, when the next disturbance comes in, with cold air in place. Temps will warm rapidly as the associated front approaches and there should be considerable rain shadowing from Seattle northward. So it is possible that some locations will initially see some snow (particularly south Tacoma) that will turn to rain. More on this tomorrow. But we will have a sunny day on Monday, with a high around 40F first...and no air pollution.
Posted by Cliff Mass at 9:37 AM