March 01, 2016

The Wettest Winter in Seattle History

Public Talk: Weather Forecasting: From Superstition to Supercomputers

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 as a fundraiser for KPLU. I will give you an insider's view of the amazing story of of weather forecasting's evolution from folk wisdom to a quantitative science using supercomputers. General admission tickets are $25.00, with higher priced reserved seating and VIP tickets (including dinner) available. If you are interested in purchasing tickets, you can sign up here

At 1 PM today, Seattle weather history was made.

Seattle has received enough precipitation since October 1 to make it the wettest winter in Seattle history.

The water year starts on October 1 and this makes a lot of sense here in the Northwest, since our summers are very dry and the real rain usually does not begin until mid to late October.  October 1-March 1 encompasses our meteorological winter and is not an arbitrary period.

Let me show you the numbers provided by Logan Johnson, the head meteorologist at the Seattle office of the National Weather Service.

Here are the record October 1-March 1 totals, with this year's total ending at 1:56 PM.

Water year to date (Oct 1-Mar 1)
  1.    38.22 2015/16  (as of 1:56 PM)
  2.    38.19 1998/99
  3.    37.96 1950/51
  4.    36.39 1995/96
  5.    36.06 1955/56
This is a major record.

A plot of the cumulative precipitation at Seattle Tacoma Airport (below) shows that we now have about 13 inches more than normal in the water year, which is very large, of course.  The second figure shows the daily rainfall and the associated records each daily (green marks).   One is struck by the  high frequency of rain this winter and the fact that only a handful of days beat daily records.  Slow and steady won the race.
Think the substantial precipitation is over?  No way.  Here is the forecast for the next 72 hr.  Black color indicates 2-5 inches.

At least the ducks will be happy.



  1. Not to be a bean-counter about it, but since we are talking about beating the the record by a tiny amount...

    Why is it natural to define winter as Oct 1-Mar 1, and not Oct 1-Feb (last)? Doesn't that make "spring" start Mar 2? Also, this winter was one day longer than the previous one. Should we normalize to per-day?

    Of course the upcoming rain renders moot the arguments about minor points of calendrical book-keeping.

    1. Probably because February has a variable finish date due to leap year... The Ides date is consistent.

  2. Cliff,
    With all these records being set, are we still within the realm of "normal" with respect to Climate Change. More and more politicians are ascribing natural disasters to CC, but I know you still firmly say ( or have in the past) that it is too premature to say so. Moreover, you have often said incorrectly ascribing these phenomena to CC does CC a great disservice.

  3. That's a good point about the extra day for leap year. Seems like it would give this year an unfair advantage. But then again it comes around every four years.


    1. And three of five of these wettest winters occurred during leap-years (1956,1996,2016). Isn't that interesting.

  4. Interesting, it sounds like petty criticism about "media" reports re: this being the "wettest" winter was unnecessary.

    Question: can people resume "complaining" about the El Nino forecasts, which readers were scolded for doing just one month ago?

    How is post-January 1 precipitation trending this year? Hmm? Still "SLIGHTLY below average"?

    Is it true that the El Nino forecasts "have actually been really quite good ..." still?

    Sure doesn't look like it.

  5. Yes wet! My fields are under water, I counted on the weather community for good forcasts last fall.. Over and over I was reassured, we had a high probability of drier than normal this winter!!!!!!!
    How come no one is accountable for the very very wrong el nino forcasts, NOAA and the media jammed down our throats for months and months. Why are heads not rolling!

    I am having difficulty supporting weather "science"... It seems voodo, coin tosses, and superstician are as accurate as " super computers". I am.loosing faith in the science with this wrong again forcast...

    Real and know, the Admiralty inlet wind warning was a bust too. Maybe 25mph tops we have had much higher winds recently with no wind advisories.

    Sorry to complain, but as a Farmer I could really use better than the mediocre forcasts we get, especially out here on the Admiralty inlet!

    Please keep trying though... The info and data is better than nothing... I do appreciate your efforts and the blog, plus the outlet for my frustrations.

  6. Even in an El Nino year (the strongest recorded on tecord).

  7. It is a truism that those who are the first to complain about paying taxes are also the first to complain when a thinly stretched government agency fails them.

  8. El Nino is dead. Long live El Nino!

  9. With a dry sumer one would logically guess the winter would be wetter. Weather always averages it self out. I work outside every day for the last 15 years and trust the 5 day forcast. Long term forcast are nice to look at but not to trust. For all the El Nino complainers stop trusting others and look outside, take a walk, get a life.

  10. The ducks will be happy, and the robins and crows and many other bird species who get a nutritional boost from eating worms that come to the surface when the soil is saturated. A little ornithology for your meteorology. :,)

  11. In your 2/19 blog post (final couple of paragraphs), you seem to endorse Oct 1 - last day of February as winter. So By adding March 1 in, we seem to be moving the goal line...

  12. Interesting that with Seattle seeing record rainfall so far this water year, the Olympic Penninsula, even the really rainy parts, didn't have a particularly extraordinary winter. A bit above average, pushing into the upper third in some areas, but not even close to record rainfall. Snow in the mountains is also about average now.

    Some have observed that's because the storms came from more of a SSW instead of SW direction this year, and a lot of the moisture moved east of the Olympics and then northward in the gap between the Olympics and Cascades. Not sure how to verify that.

    This doesn't say the SW corner of the Olympics was dry... it certainly wasn't. But places like Forks are a long ways from a record this year. The record winter rainfall in Forks was 1998/9, which was a moderate La Nina following a very strong El Nino the year before.

    Wonder if that's what we have to look forward to next winter?

    1. Yes!
      I too perceive the SSW verses SW.

      Something different going on.

  13. Hey Jort Sandwich,
    Yes, El Nino has delivered the expected weather across much of the globe including the US and Canada except for rainfall along the west coast.

    Tornados and heavy downpours are typical across the southern US during El Nino years. We have had exactly that. Temperatures at mid and northern latitudes average above normal. Central Canada and the northern tier of US states have had a warmer than normal winter, as expected with a strong El Nino.

    The PNW has experienced a precipitation anomaly. The culprit is likely warmer water around Indonesia (western Pacific). During a strong El Nino the western Pacific cools while the eastern Pacific warms. The western Pacific is still running above normal most likely the result of global warming. GW is the fly in the ointment.

    The numerical models indicate California, including SoCal, should get a good soaking through mid-March (While an MJO passes through). Hopefully, California will have a normal rain-year after a very dry and warm February.

    Temperature in Seattle has been running above normal as expected during a strong El Nino. The rainfall has been exceptional and has come in numerous moderate chunks. Despite the rainy weather, mountain snowpack is about average.

    Every El Nino is unique due to it's interaction with other global weather patterns.

    Long range weather (3 to 9 months out) may become more difficult to predict as the planet warms. We have no precedent, no weather history, for a planet that is +2 C warmer. The issue is further complicated by the warming being unevenly distributed. Barrow, AK is recording its warmest winter of record. Anchorage, AK has had only 2.5 inches of snow.

    Global warming models predict that the PNW will become wetter and warmer as the planet warms. It was wetter than expected this winter and global temperatures are running more than +1 C warmer than the 20th century average.

    I expect global temperatures to cool slightly in 2017 as either La Nina or ENSO neutral conditions develop and ocean water overturns. Ocean water surface heat will be drawn downward. Global warming deniers will probably repeat their refrain of 'global warming pause' which is ridiculous but hey they have a political agenda to maintain. I'm only interested in the science.

    BTW, I don't hear any of the El Nino forecast critics complaining about the temperature predictions! It's warmer than normal but not as warm as last winter, as forecast.

  14. Yes.. I am still waiting for that "slightly drier than normal El Nino winter".

  15. MARK: Thank you friend for that post. It is getting old listening to deniers of climate change, and sadly that same ignorance comes to this board as well. Seriously posting the same nonsense over and over only makes a denier look like an idiot. And just because somebody repeats the same thing over and over and over, does not make it true. Best post on this blog in a bit for sure. The precipitation anomaly is going to continue into next week, with heavy rains predicted over the state and some good mountain snows. This year is such a blessing compared to 2014 and 2015. At least where I am, the temps are not spiking like crazy as they did the last two years. They are following a predictable pattern, going up slow, not one day 50 and the next 70. In fact we are supposed to have a short cold spell after the weekend, but this time of year, that means mid 40s for a couple days, and then back to 50-55 which is normal behavior in early spring in Central Washington.

  16. Accounting of Leap Day met data is addressed in NWS Instruction 10-1004, available here: See Section 3.4.3 on page 9.

    At the Olympia Airport ASOS, there has been measurable precip on 109 (70.3%) of the 155 days on record between October 1 and March 3. Using the National Climate Data Center 1981-2010 normal data set for comparison, daily precip values have broken out thusly:
    > Above daily normal - 61 days (39.4%)
    > Equal to daily normal - 2 days (1.3%)
    > Below daily normal - 92 days (59.4%)

  17. I'm on the other side of the sound south of the Olympics and my PWS has me at 66.57" which is in line with Sanderson Field nearby, which counts 62.39".

  18. In Glacier (foot of Mt Baker) we had 64.23" over the five months not including snow, and there was a lot of snow. (I'd like to be better equipped to measure that)


Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

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