Northern Lights Now – The predicted G1, then upgraded to G2, aurora predicted for October 13-15 is meeting and exceeding expectations. KP values recorded in 3-hour increments by the airforce and SWPC were registering between G1 and G2 for much of the day. KP predictions from the Wing-KP model ranged from 4.67 to 7.67 from Noon GMT through Midnight GMT. SWPC has upgraded the watch level on the 14th to G3. Storming will likely only reach that level if the storm continues to intensify – and there have been some hints that it is starting to wane. Here is the chart showing today’s recorded geomagnetic activity:
At the peak of today’s storm the Bz had rotated powerfully to the south, registering as much as -20 nT. This is some of the strongest negative orientation of the Bz since the Saint Patrick’s day storm of 2015. In addition to being strongly south, the field maintained that orientation for a long time. As of this writing, the Bz had been negative for almost 20 hours. This is the longest duration negative Bz since NLN started producing this graphic that shows the duration certain important thresholds for aurora have been exceeded:
With a storm this strong, we’d normally expect to see many wonderful aurora pictures rolling in from our readers and aurora hunters. However, there were a lot of clouds in the normal viewing locations. In NLN’s HQ city of Burlington Vt it was raining most of the day and is cloudy this evening. The Moon is also nearly full, currently at 94% visible, and is washing out the aurora for people who have clear skies. That isn’t stopping photographers, and there are a few beautiful pictures rolling in. Here are a few. Please tag @northlightalert in your photos if you’d like to have them featured in the NLN blog!
Northern Lights Now – A large coronal hole pointed towards earth means there may be many as 72 hours of G2 storming between September 28 and September 30. It is likely that during that time KP values will occasionally be above 5.67 and the aurora borealis will treat Aurora hunters to a show. Refresh this page often as we’ll be posting live updates as this storm impacts Earth.
Update #11: 72:00 hours in, 0000 UTC 9/31/2016 (8:00pm EST 9/30/2016)
The interplanetary shock from the previous update did not usher in a significantly different solar wind environment. This storm has been exhausting and frustrating for Aurora hunters around the world. It’s tempting to call the storm over – the G2 watch is now expired – however, a quick peak at the SDO AIA 211 image of the Sun from yesterday indicates there may be one more round of enhanced solar wind on it’s way. Notice that there is a final “leg” of the coronal hole pointed towards Earth in the 9:00am UTC image form 9/29 in the Earth strike zone. It’s possible this will bring enhanced solar wind speeds in the second half of today. Starting in about 12 hours and lasting for between 12 and 24 additional hours will be the final chances for this storm to put on a real show. It’s frustrating, but it’s storms like this that make the storms where there is a good show that much more awesome!
The storm hasn’t been a total bust. Check out this Timelapse from Adam Hill Studios in the North West Territory:
Update #10: 69:15 hours in, 2115 UTC 9/30/2016 (5:15pm EST 9/30/2016)
It’s been quiet. The solar wind has been blowing past Earth consistently and in a non-aurora producing orientation. Until about 20 minutes ago. DSCOVR data reflected an interplanetary shock arriving, it can be seen as a sudden shift in solar wind parameters. Bz shifted quickly north, wind speed decreased and proton density dropped. Sometime this indicates a shift in the space weather environment. In this case, after a period of about 10 minutes, the Bz shifted back to the south. If it stays this way, G1 storming could pick back up. In fact, wingKP models are responding to this change and predicting a return to G1 conditions in the next 45 minutes. Here’s a snapshot of the data during the shock arrival:
Update #9: 52:30 hours in, 0430 UTC 9/30/2016 (12:30am EST 9/30/2016)
There has now been 24 hours of continuous solar wind stronger than 650 km/s. Solar wind hit a peak earlier today of over 800 km/s, which is solidly in the “very strong” range. The charged particles that are carried in the solar wind exert a force on the Earth’s magnetosphere. The force is cumulative and it acts like slowly continuing to push harder on a spring. The more “compressed” the magnetosphere is, the more likely it is to react to any periods of high proton density, strong Bt, or negative Bz. This is why magnetometers are measuring KP values in the G1 range despite only brief periods of south oriented Bz that have been occurring today.
The short story is that Earth is primed to put on an amazing aurora display if the solar wind becomes even slightly favorable for aurora. When/if it happens, there will be between 30-60 minutes of warning.
Update #8: 47:00 hours in, 2300 UTC 9/29/2016 (07:00pm EST 9/29/2016)
Wrapping up the second full day of G2 storm watch, and the third day of active storming. Today there have been 4 periods of G1 storming recorded. There should be more G1-G2 storming over the next 24 hours with the possibility for some G3 if the Bz cooperates (which it hasn’t been doing much of so far this storm.
Update #7: 36:30 hours in, 1230 UTC 9/29/2016 (08:30am EST 9/29/2016)
Since the last update, there has been nearly consistent G1 storming. Pictures of aurora and proton acrs started rolling in on Twitter. Take a look at the 6 hours chart from NLN’s current KP page showing consistently KP5+
These two twitter post show proton arcs that happened overnight for this storm, one in Montana, the other was visible in the North Caithness coast
Update #6: 29:00 hours in, 0500 UTC 9/29/2016 (01:00am EST 9/29/2016)
Just a quick update. The negative Bz did infact lead to a small substorm. KP is back to G1 levels. Check out that same webcam now, it is showing much more green:
Update #6: 28:15 hours in, 0415 UTC 9/29/2016 (12:15am EST 9/29/2016)
On of the great things about the internet is that people hook up webcams and share them with the world. Check out www.sebeclake.net where you can watch aurora live when it’s cloudy where you are. Right now, it’s clear in Eastern Main and the webcam is showing some faint green on the horizon:
On that note, after it has been quiet for the last 3-4 hours, the Bz has been oriented negative for over 15 minutes now at a strength of more than -5Bz. This means there could be a small substorm coming in the next 30-60 minutes. Watch that KP!
Update #5: 26:00 hours in, 0200 UTC 9/29/2016 (10:00pm EST 9/28/2016)
About one third of the way through the predicted duration of the late September active period and so far the storm is mostly as expected. There have been 2 periods of G2 storming recorded so far and 7 periods of G1. Solar wind has continued to stay in the range of 600-725km/s.
Those strong KP readings are all the more impressive because Bz has been variable, rarely staying negative for more than about an hour. That indicates the long duration of strong solare wind as primed the magnetosphere for a big show if there is a period of negative Bz that lasts a couple hours. Here is the 24 hour view of solar wind data, note that Bz is continuously shifting between negative (south) and positive (south) orientation (click to see full size image):
We have not seen a lot of great pictures from this storm so far. Lots of the traditional Aurora hot spots are clouded in. Hopefully it clears out for some of you over the next 48 hours. Please share your pictures with as at @northLightAlert on Twitter!
Update #4: 20:45 hours in, 2045 UTC 9/28/2016 (5:45pm EST 9/28/2016)
G2 storming is ongoing now!
Update #3: 11:00 hours in, 1100 UTC 9/28/2016 (7:00am EST 9/28/2016)
Activity has decreased a bit over the last 9 hours. One additional period of G1 storming was recorded since the last update, current KP estimates are between 3 and 4 which is not enough for most of our readers to have a chance of seeing a show.
In the lull, let’s take a quick look at NLN’s dynamic inforgraphic of DSCOVR solar wind data. The chart below shows the strength and duration of the wind. Generally, more taller bars mean a better chance of a higher KP. The height of bars indicate how long the solar wind has been favorably exceeded the threshold along the bottom. For example, below: wind speed has been above 400km/s for over 48 hours, above 500km/s for over 18 hours, and above 600 km/s for an hour. One of the most important factors for aurora is Bz, the value on the right of the chart, when it is negative and has been for more than an hour or two, that is some of the best time to go out on the hunt. The chart updates automatically – no need to refresh that page!
Update #2: 3.5 hours in, 0330 UTC 9/28/2016 (11:30pm EST 9/27/2016)
The official G2 watch period has started. There has been G1 and G2 activity consistently over the previous 24 hours, even before the offical watch period begins. This has happened without Bz making a sustained southward shift. Solar wind exceeded 700km/s for about an hour just after midnight GMT. Any sustained period of south oriented Bz could make for a very strong aurora display.
In the 0030 SWPC aurora forecast discussion, there are a pair of notes that it is possible that storming could reach G3 levels over the next three days. This would mean KP values of 6.67 and above!
Update #2: t-2 hours, 2200 UTC (6:00pm EST) 9/27/2016
The storm is rolling! G2 storming levels we reached in the 6:00pm UTC hour. Solar wind speeds are now over 650km/s and there have been periods of south oriented Bz. Here’s the reported 3-hour KP values from SWPC:
Aurora reports are already streaming in! Check out these northern lights that happened just after sunset in Iceland:
Update #1: t-20 hours, 0400 UTC (midnight EST) 9/27/2016
SWPC increases duration of storm watch to 72 hours. Here are the updated timings of this G2 storming. It is important to note that these specific timings are less meaningful in a long duration event like this as it’s likely that the exact timing of KP spikes will depend on when substorms carried by the solar wind arrive at Earth.
Northern Lights Now – The high speed wind stream from a coronal hole that was pointed towards Earth on August 21 is arriving with a stronger than expected impact. As a result KP values are reflecting an ongoing G1 level storm. The storm has allowed aurora hunters to see the lights in Denmark and Sweden and in the US in Maine. The initial forecasts only called for a period of enhanced solar wind speeds and a max KP value of 4. This is the coronal hole that is currently impacting Earth as it looked on August 21:
The high speed wind arrived earlier than expected, and stronger than expected. As an added bonus for our readers, it arrived with a period of several hours of southern oriented Bz. When the Bz component of the magnetic fields have negative readings, it means aurora are more likely. As this storm was building, it arrived with a period of over 4 hours where the Bz was negative from about 16:00-20:00 UTC. At points it was strongly negative with readings of -10Bz. This is the image of NLN’s accumulated aurora power chart from the peak of the first wave of the storm:
There are a couple interesting things to point out in that graph:
At the time of the snapshot the total magnetic field (Bt) had been strong for over 12 hours, and very strong in the last hour.
Wind speeds had really only just started picking up in the last 2 hours.
The real kicker was that Bz had been negative for over 2 hours and was as strong at -10nT (very strong) for 5 minutes.
It is rare that a coronal hole triggers all 4 of these metrics at the same time on this chart. When they are all there, it’s a good sign for aurora hunters.
Here are some of the shots that we saw come in on Twitter:
As of 3:20 UTC August 24 at the time of this writing, the storm has subsided a little. It looks like there could be anywhere from 3-6 more hours of enhanced solar wind speeds, and at any point the Bz could dip back south. If it does, Aurora hunters could be in for more of a treat. Keep an eye on the solar wind data.
Also, there is another coronal hole rotating towards Earth that has a history of producing good aurora. This could impact Earth on Aug 30th and 31st…. stay tuned!