February 25, 2011

The Olympia Mystery

You've heard of the Bermuda Triangle. Perhaps the Dragon's Triangle of the Pacific. But there is another mystery of science...the Olympia Cold Anomaly.

Its amazing and beyond our understanding.

For some reason on cold, clear nights Olympia Airport is often the coldest location in western Washington...often by far. Last night Olympia dropped to startling 5F. You heard right, five degrees above zero. It was the all time record low for the date at that site. At the same time most of the rest of western Washington only dropped into the lower twenties to mid teens. To illustrate, here are the regional weather observations at 7 AM (click to expand):Near the water, temps only dropped into the mid 20s; move more than a few miles inland and the teens were prevalent.

Lets do some more investigation--here is a close-in plot at the temperatures at the same time (7 AM Friday) around Olympia:Olympia Airport is the coldest (8F), but nearby East Olympia is close (10F).

OK, Olympia Airport is away from Puget Sound a bit..that is good for being cool, but why so horribly frigid? Could it be a topographic reason? For example, a location in a terrain bowlis often a cold spot, since the coldest air settles to the lowest elevations. Here are two topographic maps--one pulled back and one close in.Olympia Airport does seem to be in a relatively low spot with surrounding higher terrain. But I have seen more impressive terrain low spots. I should also note that the observing equipment at the Olympia Airport is the best....a NWS/FAA ASOS station--the gold standard and carefully calibrated.

Are there other possibilities of why this location is so special? I simply don't know.

By the way the Olympia cold temperature last night was almost equaled by a location in Skagit County..the Sakuma Farm AgWeatherNet site with a temperature of 5.6F. They probably grow ice lettuce there!

It is important to note that snow contributed to the general low temperatures last night for much of the region. Snow is a cold factory. It reflects solar radiation during the day and is a very effective emitter of infrared radiation both night and day. Snow is also a good insulator and prevents heat from the warm soil below (when the soil is warm, of course) from reaching the lower atmosphere. The cold records are almost always when snow is on the ground.

And talking about snow...here is a NASA MODIS image of the region today. Although some snow melted today, the snow is still pretty clearcut, as is the lack of snow over the Kitsap and the north side of Seattle. And Bellingham.

You see the band of clouds over the ocean stretching NE to SW? I bet you won't guess what that is.... a convergence zone to the lee of the Olympics. With flow from the NE, the air split around the Olympics on the NE side and then converges together on the SW side. Converging airstreams produce upward motion and clouds Pretty weird!

UPDATE: To start here is a picture of the airport from google streetview:
Low grass with surrounding trees. You can see the hills on the right side. If you want to get a really good idea of the surroundings, here is a video taken as a plane landed at Olympia Airport:

You folks are a tremendous resource. One of you Gary Burk noted the following:

The airport is called Bush Prairie after Tumwater pioneer, George W. Bush. He had a large farm there 160 years ago because that is sandy loam soils; very sandy soils. I recall visiting the westside of the runways in 1990 after a 30 hour period of 5 inches of rain. At the time I was prospecting for new youth soccer fields, but I was amazed that I could find no standing water. The Soil Conservation Service calls it Nisqually Sand formation (as I recall) now with fine sand even at 60 inches. We have two areas that soil type locally. The other is Chambers Prairie; in and south of Lacey toward WSU’s AgWeather site near East Olympia.

This is a very important point. Sandy soils are often associated with low temperatures because their low water content does not conduct heat well. But.... there was snow of the ground, which should have insulated the air from the ground temperatures. So perhaps the mystery continues. But...the soil temperature WOULD help explain part of the anomaly when snow is not on the ground...which is most of the time.

I should also note that Olympia has some of the HIGHEST maximum temperatures in summer. The sandy soils could be contributing to that, as the lack of marine influence.

One final note: I have an op-ed piece on the math standards issue in the Seattle Times today if anyone is interested.


We will dump our current math standards if the legislature doesn't act this session.


  1. Cliff, another weird anomaly. During the snow on Wednesday night I checked the WeatherBug app radar on my Android phone around 8pm I think. This radar is image always seems to be very sensitive showing very light precip not seen on other radar images. On the past 90 minutes radar animation there was a very obvious and ominous cyclonic rotation of precipitation which quickly rotated from just south of Everett all the way up to Bellingham. It seemed to stop moving north around Bellingham with its eastern edge right at Concrete, Wa on the map, Western edge was just over the sound west of Bellingham. Then it seemed to dart directly west towards the strait. T

    The snow precipitation patter changed immediately after this rotation darted north. Thats when the heavier showers moved north into Seattle and Bellevue for a little while.

    What was that "mini low"?

  2. Not to ask the obvious, but has anyone checked airport hardware accuracy? I lived about 1/2 mile from the airport and never noticed any cold bowl there. My weather station, East Oly, Lacey all agree well, then there's the airport....

  3. Has there been any research or study of how many degrees cooler snow or ice covered ground cause temperatures to be?

    Right now would be a great time to compare locales and temperatures because a lot of places have snow and some do not.

    And weather101 simply says, wind blows onshore during the day, offshore at night. Funny rules that dont always apply but....think about it, Olympia is the farthest away and lowest spot from the ocean than anywhere else in w. wash. at night.

  4. Waiting for the global warming comments to satrt rolling in.

  5. I've noticed the coldest record lows west of the Cascades are mostly from sites on the west side of the Puget Trough/Willamette Valley, and often where there are larger hills/mountains to the west (excepting along Hood Canal where of course there is a body of salt water). Olympia, Pe Ell, Corvallis, McMinnville and on down. So here's one suggestion that may be way off base - could even the coldest arctic air be warming slightly due to compression as it comes down out of the Fraser Valley and (to a lesser degree) out of the Cascades? - and could these western valleys end up ultimately colder because they are too far away & sheltered from the influence of this phenomenon if it is occurring? Yeah I know maybe not.

    That's a pretty cool, and totally bizarre convergence zone.

  6. Cliff,you forgot to mention that the Olympia weather station is protected from the wind and has calm conditions most of the time on clear nights,which helps the radiatonal cooling.Sea-Tac AP, in contrast, is situated on a high ridge,and generally has a light katabatic wind blowing from the cascades on most clear nights,which inhibits radiational cooling. I see that it`s already been down to 9 degrees F already at Olympia this evening,so it looks like another record for tommorrow.
    By the way, the 31 degree maximum at Sea-Tac today,was the FIRST EVER occurence of a 32 or lower maximum in the Feb 23-28 period in 120 years of record at any Seattle weather station.
    And, this February will be the coldest since 1989 at Sea-Tac;approximately four degrees below normal.

  7. In addition to having low thermal conductivity, the lack of ground water in the Nisqually Sand Formation would cause it to have low thermal capacitance as well.

  8. Hi Cliff,

    How do you find those MODIS images? I went to the site, but can't figure out how you found that image of the snow in Western Washington.


  9. Cliff,
    Olympia Airport appears to be at the very outer edge of the southern river of Canadian air as it veers westward across Shelton before reaching that rare convergence. Could the coldest, densest air be concentrating at that outer edge due to some trick of physics? Cold air drainage from the Cascades does not seem relevant due to the flow direction of the cold air from the Fraser, nor do the surrounding temperatures support it.

  10. The Olympia Airport, besides being a low topographic position and having sandy soils is among the most open (tree & building free, as the picture shows) but still with a significant amount of black-body blacktop, areas in south sound that also has a weather station. Trees act to reduce night time radiation back to space (as well as daytime warming). Even a mild breeze can help dissipate heat in an open space.

  11. Cliff, you might also note that summer temperatures in Olympia tend to be higher than in surrounding areas. So, you get extremes at both ends.

    Also, in the summer at least, there's almost no wind. My wife and I took a sailing class and never completed it, because there was never a day when the instructor was available and there was enough wind for sailing. This went on literally for months.

  12. Interesting post, Cliff! It would be equally interesting if readers of this blog compared our backyard temps, along with specific locale. I imagine there are places that have the Olympia airport beat, but they aren't official recording stations. And, as with the variation in recent snowfall (or lack thereof!), temps vary widely within even a small range. Just southeast of Lynden (north of Bellingham) we were still below 10 degrees at 8 a.m. Friday morning.

  13. Regarding the math standards, who is NOT for keeping the current standards, and why? Your position seems so clear cut, it causes me to wonder why anyone wouldn't see it that way, but since it's not resolved yet, there must be "another side" to this, even if it is just lethargy, fear of taking action, or momentum.

  14. RE the mystery: I got your book for Christmas, and started looking at the mystery with all my newfound knowledge ;-) Very cool.

    RE the math standards: My kids are naturally good at math, but they didn't start "getting" it until the new standards came into play. Keep preaching this...and thanks!

  15. Oly also seems to be one of the warmest spots in the summer as well. My mother lives at Lawrence Lake (on your topo map SE of Rainier near Shell Rock Ridge) and it often seems to freeze much harder in the winter and bake much higher in the summer. In the winter of 03-04 I recall the NWS issuing a Winter Weather Warning for Lawrence Lake specifically and we got 12" of snow in a few hours when most of Western Washington got a trace to nothing. They nearly had to chain up to take me back for Winter Quarter to start at UW the next day. (The only day UW ever cancelled classes for snow during my undergrad years.) Is this because of the topography out on the Yelm prairie? We also hear a lot about the Chehalis Gap, but aren't exactly sure if that comes into play at Lawrence Lake or not.

  16. I live in Olympia and lately have noticed several anomalies about the low temps reported by the Oly airport (KOLM).

    I'm a crazy plant collector and have about 4000 ornamentals in the yard, so I'm keenly aware of the weather, wet and dry, cold and hot. I deployed a couple of remote temp sensors outdoors. One is located about 18" from the ground on the north side of an old apple tree.

    Up until a few days ago, my apple tree low tracked KOLM's low very consistently, reading about 5F higher. (I'm not on the prairie but on a low ridge above Budd Inlet, less than a mile from downtown.)

    However, on the morning of Friday the 25th, my overnight low showed 19F, while the airport's was reported as 5F. The 5F looks like an anomaly, because their timestamped lowest temps show 9F at 6:03, 8F at 6:54, and 9F at 7:41.

    Also, at 11:54PM the previous (24th) night, KOLM reports a fall of 15F in about 2.5 hours (from 27F to 12F)--that's pretty unusual for that station. As if a mirror image of that slide, KOLM reported a rise of 15F from 6:54AM to 9:43AM.

    As for the most recent readings, this morning they reported a low of 8F around 4AM; my apple tree low was 17F. -- G

  17. David said: "What was that "mini low"?"

    That was no low (I think). That was the artic front from the cold air flowing out of the Fraiser and down the Sound marked out by precip in the radar.

    You can see it in this (though it disappears mostly when it flows through the snow shadow.


    You can see there is no rotation in the velocity plots. The rotation is an apparent effect of where the show is falling as the arctic front moves by.


  18. The MODIS snow cover photo provides a great demonstration of what should be thought of as the Fraser Valley. No snow in the Fraser Valley.

  19. Could it be related to the super mysterious 'Mima Mounds ' near by.

    I think the only reasonable explanation has something to do with space aliens? Not sure what, but I'm sure it must ... maybe.

  20. Great blog, Cliff!

    RE the oddly low temperatures at the Olympia airport. I was looking at the surrounding terrain with the 'terrain' function of Google Maps as well as 3D in Google Earth. I live in Northern BC so I am unaccustomed to Washington State weather.

    Is there often outflow to the coast from the south Puget Sound basin through the Chehalis River valley? The airport looks to be located at a funnel point for air from the south of the basin as it goes south along the Black River then west along the Chehalis. There are slight 150-200' topographic features surrounding the airport to the south and steeper ones to the west, enough to form a funnel. I imagine times when this funnel forces cold air to pool in the airport area prior to outflow.

    Is there nearby weather station data to model to confirm this may be the cause? Can it be this simple or am I being naive?

  21. Ok, figured out how to search through the MODIS images. Take a look back to just the 19th (6 days before that image) and you can see how much a difference in snow coverage there is. Also interesting is you can see the layering and how some places were hit more heavily than others.

  22. And another piece of trivia, completely unrelated to weather: George Washington Bush was a free black man who came west on the Oregon Trail with his family. At the time the area from the Columbia River northwards was still controlled by the British Hudson Bay Company, who had to be petitioned to let an American settle in their territory. This was necessary because the Provisional Government of Oregon to the south did not allow blacks to own land. Previously, American settlers were not allowed in this area.

  23. Kevin, I noticed in the late Wednesday 4km model as I went searching after I saw it on the radar. I can't find the exact 4km chart I did the other night, but you can still see it in this one http://www.atmos.washington.edu/~ovens/loops/wxloop.cgi?mm5d3_ww_slp+2011022400///3

    In real life it occurred much faster than what the model forecast shows. I think it started about 6:30pm and made it to Bellingham by 8 or 8:30 pm, and I lost it as it darted west. I had never seen something like that roam through the precip before and was pretty impressed when I found it on the 4km fcst models.

  24. Interesting stuff! Reminded me of Peter Sinks, UT reaching -69F. Maybe the height of the thermometer is contributing the the low temps??

  25. Cliff:

    Just got home after spending the afternoon and evening in a mostly snow-free Bremerton... I am 3 miles NNE of Monroe at about 400' and it looks like I got about 3" of new snow today. I know it was predicted 1-3", just thought it was worth noting the NWS hit the nail on the head.

  26. I have to disagree with you about the math standards. I'm not sure you really understand the purpose of the common core standards. Teachers teach students the curriculum that district administrators purchase from national textbook publishers. At this point, our curriculum are written to satisfy all standards across the country. When the standards changed a few years ago, what happened in the classroom changed very, very little because we continued to use the same curriculum. With the Common Core Standards, there's a new opportunity for textbook publishers to focus their curriculum on the new national standards. We will be able to teach certain areas in depth rather than providing the wide breadth needed to cover differing state standards. There's no longer any valid reason for individual state standards. I'm not so sure why you're so leary of the OCmmon Core. They are very similar to the new math standards. Hopefully, you can take a closer look.

  27. Are the 4km and 1km high res models overestimating the amount of cold in the region this evening because they are saying 4-10" in the Puget Sound area tonight (Sunday night)!?


    The previous runs did show the strong front but it was all rain before.

    I was also curious if you, or anyone else knows of any discussion boards, chat rooms etc where weather enthusiasts can exchange ideas and talk about the models, forecasts etc. It seems like there are a number of people out there that are interested.
    It is looking like an exciting weather week coming up!

  28. Mr. Ziemkowski
    I really have to disagree with you. Curriculum matters...and several districts in our state switched to far better math books after the 2008 math standards changed. And just because standards are national doesn't mean they are good. What I am saying is that it makes no sense to jump to them in their current untested stage with no assessments...and particularly since they are so poorly written. HAVE YOU READ THEM? If not, do so and then let me know what you think...I suspect your answer will change...cliff


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

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