Update tonight (Wed) at 10:30 PM on new blog
BIG NEWS UPDATE at 10:15 AM Wednesday: At 10 AM, Seattle-Tacoma Airport reported 65F, the WARMEST TEMPERATURE EVER OBSERVED AT SEA-TAC FOR THE MONTH OF DECEMBER. I repeat this is the warmest temperature every reported for any day in December in the entire climatological record. Amazing. Undoubtedly true of other Northwest sites as well.
I had to laugh today when I saw the front page of the National Weather Service's Seattle forecast office web site.
They had FOURTEEN watches, warnings, and advisories.
I have never seen so many. Something out of a disaster movie or reminiscent of the plagues that hit Egypt before the Exodus. High Winds! Floods! Small Craft Advisory! High Surf! Gales! Storms! Rough Bars! All that was missing were tornadoes, hurricanes, lice, and darkness. Oh, I forgot, we have darkness living in Seattle during the winter.
But the extremes did not end there! Many locations got above 60F today...some into the mid-60s (see below). In western WA and OR in December! Subtropical air was over us.
We have some major winds coming and ground zero should be the Oregon coast. If you live there, get ready. Secure supplies, flashlights, and keep away from potentially falling trees. But it will be glorious for storm chasing. (I tried to convince some folks along the Washington coast (including the Mayor of Westport) to start a storm museum and have storm gatherings there during the winter. It could be a huge tourism magnet. Filling the hotels, B & Bs and restaurants. They laughed at me.)
A trough will come through Wednesday AM, with wind gusts reaching 60-70 mph (see graphic for 10 AM Wednesday). The whites and purples along the coast will be the danger zones. There is substantial confidence this is going to happen.
But what you are really interested in is the major coastal cyclone that has been advertised for Thursday. This is a really interesting event for me. Rarely do you see the major forecast models in such disagreement this close it to an event.
On one hand, there is the U.S. GFS model, which has been going for a big event for a few days. The latest run tonight still has a powerful storm, but farther offshore, so a bit less threatening for Washington and particularly Puget Sound.
Here are the latest pressure forecasts from the UW WRF model. A 974 hPa low off of northern Oregon at 1 PM (21 UTC) Thursday. LARGE PRESSURE GRADIENTS along the Oregon coast.
By 7 PM, this fast-moving low reaches Vancouver Island, but has weakened to 981 hPa. Very strong winds along the coast (gusting to 60-70 mph), but far less over Puget Sound. Perhaps gusts to 40-50 mph here.
What about the nemesis of the National Weather Service GFS, the super-duper European Center Model driven by big computers and better data assimilation than used in the U.S.? It has had much more benign solutions. BUT, it has now come much more into alignment with the U.S. model, although a bit weaker (see forecast for sea level pressure and relative humidity for 4 PM Thursday). Large pressure difference along the Oregon Coast.
Perhaps this is going to be a big win for the American team! We will see soon enough.
This is a very difficult forecast. Small storm, which has not even formed yet. Substantial uncertainty. Amazing we can even attempt to make such forecasts.
But it is getting very clear that the Oregon coast is going to be ground zero for a major onslaught of wind. Hurricane-force gusts.
And there are so many weather stories that I don't have time to discuss, like the extraordinarily heavy rain that is about to hit northern California. A drought buster.