Northern Lights Now – An extended period of high solar winds, the result of a large Earth-directed coronal hole, put on a three day long show for aurora hunters in high latitudes in early March. Photographers captured aurora glows, pillars, picket fences, dancing displays and illuminated night landscapes from around the world between mid March 1 through early March 4. Here’s a spectacular time lapse video from Adam Hill showing a wave of northern lights racing westward through the sky.
This extended storm was measured by the Space Weather Prediction Center (SWPC) as 9 periods of G1 storming and one period of G2 storming over 66 hours. G1 storming means the KP reached 4.67 and aurora can be visible as far south as Toronto, the upper midwest in the United States, Seattle and Scotland and can be seen as far north as Invercargill and Tasmania in the Southern Hemisphere. G2 storming means aurora can be seen at even lower latitudes near cities such as Portland, Boise, Dublin, Hamburg, Moscow and Christchurch. This chart show the first 5 days of March with the G1 and G2 3-hour periods showing in Red.
This early march storm is the result of a coronal hole that was pointed towards earth at the end of February. The hole is shown as a dark area on AIA 193 in the image below. It exposes the high speed solar wind emanating from the solar surface. Here’s an image of the coronal hole from the Solar Dynamics Observatory:
Those high speed solar winds take 2-5 days to arrive at Earth, and when they do they push on the magnetosphere and can cause aurora. This means that when there is a coronal hole pointed towards Earth solar scientists can predict that there is a good chance for activity 1-3 days in advance. Watch for those predictions on the NLN 3-day aurora cast – potential G1 storming shows as orange on those charts.
Let’s enjoy the view! Here are a few of our favorite tweets from this storm:
Watch the cloud clear and the lights come out to play in this time lapse
Northern Lights Now – There is a 72 hour G2 storm watch in effect from October 24 through October 27, NLN will be live blogging the storm here. Please check back often
Update #10: 0300 UTC 10/29/2016 (midnight EST 10/29/2016)
Earth has been under the influence of that large coronal hole for over 4 days. The last several days have been less exciting than the first day and a half, but over the last 3 hours, activity has picked back up. G1 storming conditions have started up again. Here are the current recorded KP values from Boulder:
The storming is showing up vibrantly on the Tromso all-sky cam. It’s clear there, the moon is nearly new, and the Aurora is filling the sky!
It’s possible this storming could continue several hours. Keep an eye on the KP.
Update #9: 2300 UTC 10/26/2016 (7:00pm EST 10/26/2016)
As evening sets in across the East Coast, the KP drops. KP=4 in the short term forecast. It could go back up any time.
Update #8: 1700 UTC 10/26/2016 (1:00pm EST 10/26/2016)
An two hour period of Bz south from about 14:45 to 16:45UTC pushed storming levels back to G2 (KP=5.67 and above) since the last update. Conditions continue to be favorable for northern lights and will likely to be for the next 12-24 hours at least. Here’s a snapshot of the current recorded KP from boulder, where the most recent period of G2 is visible.
If you are planning on going out tonight, you might want to check out NLN’s handy Last Minute Aurora Viewing Preparation Guide, there are some great tips for what to do before you go out and while you are out. Please bundle up! It’s cold across much of the northern viewing spots and you may be standing still for a long time.
Update #7: 1400 UTC 10/26/2016 (10:00am EST 10/26/2016)
Solar wind speeds have now been elevated for over 24 hours. The big winners from last night’s aurora hunt seem to have been in Europe with some terrific images coming from Denmark.
Update #6: 0345 UTC 10/26/2016 (11:45pm EST 10/25/2016)
Last update for tonight. Solar wind is has exceeded 800 km/s and is in the “very high” range. It does appear that wingKP continues to over estimate the actual KP. There is still enough activity that high latitude clear locations should get a show. Keep an eye on the Bz, if it goes back south for another extended period, there could be a new substorm at any moment.
Seven games is a long series. There is plenty of time left for a comeback.
Update #5: 0200 UTC 10/26/2016 (10:00pm EST 10/25/2016)
Let’s go Cubs! It’s the 6th inning and the Indians are leading 3-0.
The solar storm is continuing. Bz has been variable for most of 10/25 UTC, but there were some periods where there were extended periods with negative Bz. In the spirit of baseball, here’s a random statistic: Of 1440 total minutes in the day, Bz was only negative for 458 of them.
Update #4: 2130 UTC 10/25/2016 (5:30pm EST 10/25/2016)
It is now dark in Europe and reports of Northern Lights are rolling in. WingKP predictions have been consistently in the 5.67-7.67 range for the last several hours. It’s important to note that when the wind speed is high and there is a particularly strong ground reading (like the G3 mentioned in the last update) that the wingKP model can overestimate. Even with the overestimate, there is still very strong active storming ongoing now.
About an hour ago, Bz shifted to into a new and solidly southward orientation. It is evident in the graph below starting at about 20:45 UTC. This should give a very nice substorm to Aurora hunters out under the lights for the 45-70 minutes (click the image for full screen).
Here are some Photos from Twitter. Thanks for sharing!
Update #3: 1630 UTC 10/25/2016 (12:30pm EST 10/25/2016)
Exciting times! SWPC at Boulder reported a period of G3 storming over the last three hours. Current KP predictions are showing consistently G1-G2 storming. Solar wind conditions are favorable to aurora hunters. Make sure your camera batteries are charged, and check out your cloud cover forecast.
Update #2: 1300 UTC 10/25/2016 (9:00am EST 10/25/2016)
Solar wind speed has increased to over 600 km/s, and there have been periods of Bz south overnight. The first wave of G1 storming of this storm is predicted in the next 50 minutes or so, with an expected KP of 5.33. There were a couple Twitter reports of Aurora overnight, here’s one from Corinne in Northern Wisconsin
Would you like your photo shared in this live blog? Share it on Twitter and be sure to tag @NorthLightAlert
Update #1: 0300 UTC 10/25/2016 (11:00pm EST 10/24/2016)
One full day into the watch period and the high solar winds are running a little late compared to the forecast. Late on 10/24, winds started to increase to 450 km/s. Over the next 6-8 hours they could increase to as much as 700 km/s. There haven’t been any KP=5 active periods yet, but there has been enough activity for some sporatic reports of aurora in Finland and Iceland to trickle in. Stay tuned, there is likely more to come. Take a moment to appreciate how large this coronal hole has become, in the AIA 211 image in encompasses most of the visible solar disk
Northern Lights Now – A somewhat complicated aurora forecast for G1 storming Oct 22nd and 23rd kicks off what may be a long duration aurora event this week. Let’s break it down and help explain why space weather forecasters think this could be an exciting week.
First, coronal hole on the surface of the Sun rotated into the Earth strike zone on October 19. Coronal holes appear as dark areas when viewing the sun through a 211 angstom filter. This particular hole measures in as “relatively small,” but is still 20 times the size of Earth. As coronal holes rotate with the Sun, they track across the Sun’s surface from East to West or from left to right in most images you see of the Sun from satellites. The area near the center of the visible solar disk is the Earth strike zone, when coronal holes are in that area, they send high speed solar wind towards Earth. It typically arrives at Earth about 3 days later, when any disturbances or ripples in the wind have a higher than usual effect on Earths magnetosphere, prompting the possibility of aurora. Here’s an image of the coronal hole when it was in the Earth strike zone on the 19th.
Typically the best chances for aurora are at the time the higher solar wind begins, again after it has been high for a long duration, and finally when a disturbance traveling on the wind arrives. When the wind first arrives, it is carrying additional protons that it has “swept up” as it travels from the Sun to Earth. Those particles were moving towards Earth but at a slower speed. When it arrives, it appears as a sharp change in the solar wind data being read from satellites in a pattern know as an “interplanetary shock”. As the storm continues, it has a cumulative effect on the magnetosphere, “pushing it” as though it is a spring. The more compressed that spring is the more sensitive and responsive it is to regular disturbances that constantly emanate from the Sun and travel along the wind stream.
Most of the time those disturbances are small. Their sources can be seen in the normal movement in the Sun’s corona in time lapse video from sites like SDO. Occasionally, there is a larger eruption either from a flare or a filament that adds to this background activity.
On October 20, one of these larger eruptions took place in the form of a filament on the surface of the Sun erupting from an area just north of the coronal hole. The eruption launched a large cloud of plasma and particles, known as a CME or coronal mass ejection, moving toward Earth. It will arrive at Earth while the magnetosphere is still activated from the high speed wind, and so could produce an aurora show. Filament eruptions like this are stunning! This time-lapse of images from SDO shows the filament erupting over a period of about 18 hours, imagine the material flying out into space and towards Earth.
High solar wind and an arriving CME alone isn’t enough to ensure aurora. The orientation of the plasma cloud has to be just right. As of now, it is impossible to know it’s orientation until the leading edges start arriving at Earth. This means it is difficult to predict the exact timing and duration of the aurora storm. There could be none at all. When it arrives, expect proton density and Bt to increase on the DSCOVR solar wind page. If the Bz goes negative, it means the CME is oriented the right way for aurora if it goes positive or stays positive, there won’t be aurora.
A the tail end of the expected impact from the CME, Earth will fall under the influence of yet another coronal hole. This coronal hole is just rotating into the Earth Strike zone now. This one is much larger. When fully in view it will cover nearly 20% of the solar disk stretching from just south the equator to the Northern Pole of the Sun. This coronal hole has been visible every 27-28 days for the previous three rotations of the Sun. During it’s last rotation it produced 3 days of activity which occasionally reach G2 storming levels. The structure looks similar so it is likely to be equally as strong and have a similar duration. Long term forecasts are predicting there may be KP 5 through the end of the month making this an extremely long period of potential storming. NLN will be continuing to post additional updates on this coronal hole, and any events that happen near it, over the next several posts.