December 30, 2015

Aurora Borealis Over Washington State Tonight?

8 PM Update:  Here are the latest forecast graphics from the Space Weather Prediction Center for 10 PM to 1 AM and 1 AM to 4 AM.  They are bringing the viewable aurora into us.

  I am certainly going to be out there.  A good aurora provides an almost religious experience.

There is a chance that there will be a celestial show on tap for tonight over Washington, if you can get to a location away from lights:  an Aurora Borealis.

The reason?  Their was a massive solar storm on December 28th, called a coronal massive ejection (CME) and the particles are reaching the earth today.

The NOAA Space Weather Prediction Center provides forecasts of the Kp index, a measure of the geomagnetic disturbance of the Earth's magnetic field by solar fluctuations.   Large Kp values are associated with enhanced auroral activity. The time  used is universal time (UTC or UT).   4 PM PST today is 0000 UTC 31 October.   We had a major geomagnetic event Wednesday (peaking between 7 AM and 10 AM) and it will be declining this afternoon.   But it will still be fairly strong this evening.  So there COULD be auroral activity tonight.

The Space Weather Prediction Center also has an aurora forecast graphic.  Here is their prediction for early tomorrow) (Thursday morning (1 AM to 4 AM).  I you look carefully you will see we are within the fuzzy green...not the highest probabilities, but a possibility.

What about the weather?  We will have PERFECT viewing conditions with clear skies and fine visibility.  The visibility satellite image at 1 PM says it all:

The key is to go some place that is dark...away from lights.  The latest aurora diagnosis/short forecast for 2 PM  our time shows a high probability of aurora over northern Europe.  That band will rotate towards us tonight.

There are no guarantees, but it may be worth your while to take a look outside during the early evening.   Auroras are magical apparitions to view.


  1. where do you recommend going to see the show?


  3. where do you recommend going to see the show?

    Probably outside

  4. Probably not gonna happen. This event is shaping up to be weaker than forecast. Kp peaked at only 4 and is now declining.

    1. This event was a multiple CME so watch for further reverberations in the geomagnetic field.

  5. currently has us well outside the auroral oval and said that the CME was not strong enough to generate a big aurora event. Too bad, because you're right, except for being quite cold, the weather is perfect. Just spent 10 minutes outside in our darkest part of the yard and saw two meteors and a couple of satellites but no aurora. C'est la vie.

  6. I tried viewing off & on from ~ 1am - 3am with no luck. Any other reports out there?

  7. Nothing yet by 0330 December 31 PST from Whiskey Creek Beach, located on the bluff above Srait of Juan de Fuca 20 miles west of Port Angeles. Superb viewing weather, clear north with only a little fog above the Strait. Pretty bright moon, tho.
    Please post if you do have a sighting....

  8. One can see some faint aurora earlier this morning to the NNE on the Skunk Bay webcam time lapse, from around 5-6AM. I couldn't see any out my window here near Kingston. Hopefully tonight will be better.

  9. Check out for updates on our geomagnetic shield as well as other important spaceweather information. We have only managed to hit a Level 2 geomagnetic storm, and alas, the sun has risen...

  10. I used to run an aurora detection system in the Walla Walla area (filtered photometer coupled to some software and a large mailing list). Unfortunately, one quickly learns that space-weather news in the media are almost always incorrect. They latch on to relatively minor events on slow news days and hype them up as a "massive solar storm" or whatever. To be fair, even the most ordinary of these events involve scales and energies which are hard to wrap your head around. But sadly, they aren't all going to produce a stunning aurora in WA.

    Happily, there are some rules of thumb anyone can use to beat the media many times over at forecasting and nowcasting the really big storms. All the data you need are here:

    1) The causative event is almost always a large solar flare, of long duration, from a sunspot group well placed near the center of the solar disk. Flares are rated by X-ray emission. "M" class is moderate, "X" is major. You usually want high M or X. This one was M1, rather weak.

    2) The CME (coronal mass ejection) should be seen as a "full halo" event in the SOHO LASCO data (blue animation). In the animation it will appear as a big puff of smoke, in all directions from the solar disk. That means it's headed right for us. This one was mostly full-halo. Check.

    3) The CME cloud now has to travel to us. There is a very strong correlation between transit time and magnitude of the resulting disturbance. In my experience, two days means a fair-to-middling storm at best. The big ones are almost always one day transit, the historic ones, less than a day. (Carrington event was < 18 hours.) This one took two and a half days: not good.

    4) Finally, the magnetometer on the ACE spacecraft, a million miles upstream, gives us 30-60 minutes advance warning, enough time to delay leaving the house until the impact is imminent. See the red "Bz" curve on the "ACE MAG and SWEPAM" plot at the referenced site. It needs to be negative, large, and relatively flat for several hours at least. So yesterday you could have waited to leave the house until 10 or 11 hours UT, with absolute confidence. Nothing happened at earth until ~ 12 UT.

    5) Timing is everything. The peak of a magnetic storm may only last 4-6 hours, especially for a minor storm like this one. If it doesn't get rolling until 4 a.m., like this one, your best-case scenario isn't that great. CME impact at mid-day or early afternoon is best. Forget the advice to try again the following night. That almost never works, unless even the faintest glimpse of aurora will have you swooning with joy.

    Finally, if everything *does* line up, don't let the weather be a deciding factor; drive as far as you have to. You may not get another chance.

  11. Image here (scroll down):

    They showed up in Seattle.

  12. I live in Bridgeport and I just witnessed the northern lights.


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