Thursday, November 17, 2011
I’ve got some great news for all you snow lovers! The new 12z model runs came out this morning, and both of our high-resolution models at the UW are pointing to a bit of snow in the Western Washington lowlands! This is the first run that has really shown some snow, so I am not completely sold on the idea yet, and the snow predicted is pretty light and spotty, with Seattle not getting much at all. However, it is an encouraging sign. The models late this evening will give us a better idea on whether we can expect to see snow or not.
Yesterday was a pretty interesting day for weather. We saw some pretty gusty winds and heavy rains over the area. I live on the 8th floor of a south-facing dormitory, and the winds were really blowing last night! I decided to open all the windows for a couple minutes, and all of my papers were flying all over the place. It was pretty cool.
Here is some data from the UW atmospheric sciences for the last 24 hours as of 1 P.M. PST today. Click on the image to enlarge it.
You can see some pretty strong winds, with gusts approaching 30 knots! Also, look the beautiful pressure trace. You can see a clear minimum from 10 P.M. last night.
Now, let’s look at some of the snow forecasts for our area. Right now, it seems our best shot for snow is Friday night into Saturday morning.
Valid 10:00 pm PST Fri, 18 Nov 2011 – 42hr Fcst – UW 12z 4km WRF-GFS 3-hour snowfall
As a low pressure system passes to our south, northeasterly winds will start to flow out of the Fraser River Valley. As these winds hit the northeast side of the Olympics, they will rise, creating clouds and snowfall near Sequim. Sequim is usually the driest place in Western Washington, but it looks like they’ll be one of the snowiest places in the next couple days!
Valid 04:00 am PST Sat, 19 Nov 2011 – 48hr Fcst – UW 12z 4km WRF-GFS 3-hour snowfall
As we get into Monday morning, things become more interesting. We have snowfall north and south of Seattle. Things could change though, so this situation bears watching.
Heavy rain is still on tap for next week, though, and if the models are correct, many rivers off of the Olympics will flood.
Valid 04:00 pm PST Tue, 22 Nov 2011 – 132hr Fcst – UW 12 12km WRF-GFS 24-hour precip
Look at that! 5-10 inches of precipitation on the Olympics! Right now, Seattle doesn’t look too bad, but that could change if this band of moisture moves a little bit south. This is a classic “Pineapple Express” event, as a large stream of subtropical moisture looks to be aimed right at the Pacific Northwest. The snow levels with this system will be high, which is not good for flooding concerns or ski resorts.
I got to go now, thanks for reading!