To try to quantify our plight, I and other local weather scientists have developed a new, and I hope, authoritative measure of interesting weather here in Seattle:
The Seattle Winter Excitement Index (SWEI). (correct pronunciation is "swee")
SWEI is calculated over the core of Seattle's winter (Nov. 15-Feb 15) and is the sum of several components parts:
(1) The number of days the temperature exceed 60F or drops below 25F.
(2) The number of days with two inches or more of precipitation.
(3) The number of days with sustained winds of 30 kt or more.
(4) The number of months with more than 1 inch of snowfall.
All inputs are from Seattle Tacoma Airport. I should note there are rigorous reasons for each of the above criteria. For example, many official groups (like this National Weather Service site) consider that hard freezes occur below 25F. Plants die. Local meteorologists note that wind damage often begins when sustained winds hit 30 kt or more. And local mayors confirm that even 1 inch over a month brings tension, excitement, and danger to local roadways. Folks, this is rigorous science.
I asked my department's star data analyst, Neal Johnson, to run the numbers for the entire record (1948- today) at Seattle Tacoma Airport, the main climatological site for western Washington.
The results are in. Be prepared for sobering news.
This winter is the most boring and uneventful based on the SWEI index described above. Actually, we are tied for most boring with 1963-1964. Specifically, 2012-13 and 1963-1964 had the lowest values of the SWEI index.
Only old-timers who can remember back nearly FIFTY YEARS can wax nostalgic about such a boring winter. For the quantitative among you, here are the ranks of the top boring years (a lot of ties)
The signs of profoundly boring weather is everywhere. For example, the latest snow pack map shows that, well, we are averaging near 100% (see below). Big surprise.
Or plot the cumulative precipitation at Sea Tac and compare to climatological values over the last three months (see graphic). We come out very slightly below normal. And no big one-day precipitation event. Long periods of virtually nothing. Yawn.
The best we could do in extreme weather this year was an extended period of low-clouds/temperature-inversion and one incident of high tides, the later mainly caused by astronomical features and a modest low. Not good enough. No wonder the Weather Channel has ignored us. Jim Cantore will travel elsewhere.
|Extreme Weather in Seattle|
I do not have an answer.
But I have heard that some folks at the web sites Skeptical Science and 350.org have suggested that such extremely boring weather is "consistent" with what one might expect from increasing greenhouse gases in the atmosphere. Time will tell.
I realize that there is some danger in writing this particular blog. Like putting a red flag in front of a meteorological bull. But I am willing to take the risk and quite honestly we need some excitement around here.