Friday, February 19, 2016

Is it REALLY the Wettest Winter in Seattle History?

There is a lot of talk about this being the wettest winter in Seattle history, including stories in the Seattle Times and on local TV stations.   But, as in everything, there are subtleties, and such details may rob this year of the number one title.

The record winter talk was started by my colleagues at the National Weather Service, who noted in their twitter feed that during the last 24 hr Seattle had achieved a record rain total for December, January, and February (see details below for numbers as of this morning) for the period going back to 1894. At that point we were ahead by .01 inch, but we got a lot more rainfall today and there will be more during the rest of the month.


The biggest reason we broke the record was our extraordinarily wet December (11.21 inches, 5.86 inches above normal).

Now although some folks might think of December, January, and February as winter, it really doesn't represent meteorological winter in the Northwest or astronomical winter by the normal definition.  November is a big rain month in our area, so lets look at the November through February total, which is much more meaningful (thanks again to Logan Johnson of the Seattle NWS office for these numbers).   A somewhat different story, with this year falling back to fourth place (yes, still impressively wet!).


Today we had nearly a half-inch in addition and more rain will fall this month.   There is a very good chance we will move into second or third place, but I suspect our chances of moving into first place are slight, with an extensive dry period ahead this week.

But using November 1 is still a bit artificial.  Let's try using the start of the water year, October 1.  That makes more sense, since we tend to be quite dry before that and many years see serious rain starting by mid-October.  Again, the National Weather Service to the rescue....here are the totals since October 1st. Wow...we are in second place!  Impressive.  But we are quite a bit behind the leader (1951).


Now the competitive folks among you are asking, might we beat 1951 later in the season?  It is possible, but we are starting 1.4 inches behind and next week will be pretty dry.

Any way you cut it, this has been a very wet winter...certainly in the top 5.   But  I would refrain from giving us the number one title, as some local media are trying to do. What makes it even more impressive is that this is a strong El Nino year, which generally results in modestly below normal precipitation after January 1.
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Public talk on March 16th in Seattle to raise funds for KPLU:  Weather Forecasting:  Humanity's Greatest Achievement?

I will be giving a talk on March 16th at 7:30 PM in Kane Hall on the UW campus on the history, science, and technology of weather forecasting.  It should be a fun presentation that will trace the development of weather prediction from ancient times until now, including some offbeat aspects you might not have heard about.  The history of forecasting is quite fascinating, including characters like Aristotle, Benjamin Franklin, Captain Robert Fitzroy, and many others.  Modern weather prediction is perhaps humanity's greatest achievement, using the most powerful supercomputers and billion-dollar satellites, dealing with phenomena from the microscopic to the planetary scales.  Weather forecasting is not only science; there is a  religious element to it as well and represents a task that can only be accomplished when mankind works together.  The talk will end by describing how weather prediction technology is being used to help understand and plan for climate change.

This talk is being given as a fundraiser to help raise the money needed to keep public radio station KPLU alive.  General admission tickets will be $ 100 and VIP tickets that include dinner are $1000.  If you are interested in purchasing tickets, you can sign up here.  

Whether KPLU will survive depends upon the station raising 7 million dollars by June 30th.  If they do, an independent KPLU will born and your favorite KPLU programming will be maintained and expanded.  If KPLU fails to raise the funds, the station will be purchased by KUOW, which will fire the staff and take over the transmitters.

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