Northern Lights Now – SWPC has issued two geomagnetic storm watches for G2 storming (KP=6+) on August 2nd and G1 storming (KP=5+) on August 3rd. These watches are the result of a pair of solar features that will impact Earth starting midday UTC on August 2nd. The NLN AuroraCast shows the current predicted timing for the timing. As always, these can be within +/- 6 hours:
Please visit NLN’s live blog of this storm and follow out Twitter feed for the most up-to-date information.
The first solar event that will impact Earth is the arrival of a very slow moving CME (Coronal Mass Ejection) that was launched during the July 28th filament eruption. The eruption happened almost dead center (near N01E06) on the solar disk. The associated CME was estimated to be travelling at 125-150 km/s. At that speed, it could take as many as 7 days for the CME to arrive at Earth, but it should be pushed by the ambient solar wind to 350 km/s or so. Then, an even higher wind from a coronal hole high speed wind stream should push it even faster to 600-650 km/s. There are several factors making the timing on this forecast complex – current models show the CME arriving midday to late August 2nd, 5 days after it’s launch.
In the animated GIF below watch the filament eruption in a composite of AIA 211, 193 and 171 wavelengths. These frames are about 14 hours of images taken by the Solar Dynamic Observatory (SDO) cameras. Note that just to the east (left) of the eruption, the coronal hole rotating into center disk is visible as a darker area:
The second feature is a large coronal hole that rotated into geoeffective position on July 31. The high speed stream from this CH measured at STEREO Ahead indicated that winds could reach 650-750 km/s at L1. This very strong wind will likely start impacting Earth either with or just after the CME arrives. If it “pushes” the particles in the CME, they will arrive at the leading edge of the shock. Due to the elongated shape of the CH, the period of elevated winds could be extended in duration. Here is an image of the coronal hole from SDO in AIA 211 from July 31 as it rotated toward Earth:
Together these storms have the potential to arrive with a strong shock and an extended period of high solar wind and active geomagnetic conditions. If they do, it should be a very good couple of nights for aurora hunters worldwide. As an added bonus, the Moon will be waxing just past new, so skies should be dark.
Amazing – More than 24 hours after the predicted arrival of the Feb 11 CME, space weather activity has increased. Bz just dived to -6, while Bt has been above 20 and wind speed is increasing. We may get KP=5 yet! KP is currently t 4.33, and it could easily climb over the next hour.
The interesting question presented by this data: Is this the arrival of the predicted CME, or is this a disturbance traveling along a slightly elevated wind stream?
Update: 17:30UTC Feb 15 (12:30pm EST)
We’re calling it. This storm is a miss. There is no indication that is approaching.
In the image above, if you expand it and look closely, you could almost make a compelling argument that the CME arrived between 5 and 7am GMT (during our last update) as the density is consistently above 10 p/cm3.
Time to look forward to the next potential solar storm. Luckily for aurora hunters, the wait won’t be long. On Wednesday the high speed stream from the northern extension of a southern pole coronal hole should arrive at Earth and bring with it a chance for activity. Stay tuned for a post about that.
Update: 12:30UTC Feb 15 (7:30am EST)
The CME arrival is now officialy late. It is either moving very slowly or it missed Earth. SWPC has updated their forecast and is now calling for the arrival about 6 hours from now, here’s the updated NLN 3-day AuroraCast showing the updated forecast from SWPC:
This means we’re still in wait-and-see mode. Though every hour that passes without a sure sign of the arrival means it’s more likely this was a dud.
Note in the image above a new period of G1 storming is predicted on day three. This is due to the coronal hole that was pointed towards Earth yesterday. There is a new watch posted for this period. NLN will make a new post about that watch soon.
Update: 06:00UTC Feb 15 (1:00am EST)
Over the last half hour there has been a marked increase in proton density. Readings have sustained above 10 p/cm3 with occasional spikes above 18. Earlier these reading were between 5 and 8 with occasional brief spikes. This is an indication that the CME is arriving. In addition to the proton density, Bt measurements have shown a couple abrupt changes in the last hour. Both of these indications say that the CME shock could arrive in the next hour or two, with the impact at Earth about an hour later. Here’s the current data from spaceweatherlive.com (where you monitor ACE satellite data in near real-time):
Over the next two hours, watch for more sudden jumps in Bt, proton density to increase to 20 with spikes above 30, and the solar wind speed to pick up. As the CME shock arrives, all measures should show significant changes. Once that happens, watch the Bz. If the Bz shifts into negative territory, it means the CME is oriented correctly to produce aurora on Earth. Once the Bz shifts south, about an hour later the KP will rise and aurora hunters will be rewarded for the wait tonight.
Since this storm is delayed from the predicted schedule, Europeans probably won’t get to see northern lights tonight. But people in New Zealand may get a display.
It’s time for the NLN crew to head to bed. Our next post will be in the morning.
Update: 02:30UTC Feb 15 (9:30pm EST)
Hang tight! It’s not time to give up yet. It will be at least another hour before any aurora starts, and probably more – the CME has not arrived yet. While we’re waiting, here’s some aurora from Iceland in January.
The period when KP=5+ is predicted has begun. However, NLN, space weather scientists and space weather enthusiasts are still in wait and see mode. The absence of a clear indication in EPAM of the approaching CME indicates either that the CME is missing Earth, or it is moving slower than expected. There have continued to be hints of activity in the data at ACE – recently spikes in the the proton density graphs indicate there are small waves of protons hitting the satellite. Similar to the data in the 20:00 update, these could be indicators that the front of the CME is being pushed by the high speed solar wind from the coronal hole. If that’s true, the CME may have sheared while traveling through space.
As time goes on with the arrival, confidence that there will be a northern lights display decreases. However, it is far too early to make a call that it won’t happen given the data available.
Update: 20:00UTC Feb 14 (3:00pm EST)
A slight, but sudden, increase in solar wind that happened at the same time as a drop in the Bt from 7nT to 5nT just now may indicate the first hints of the CME are starting to arrive. The next 3 hours will be telling
Update: 19:00UTC Feb 14 (2:00pm EST)
As of now, there is still no definitive indication that the CME is approaching. Fingers crossed.
A quick update on the cloud cover forecasts for this evening. In the US – it will be very clear and cold in the Northeast, this should make for great viewing conditions for aurora hunters who can handle the cold. Most of the mid-west will be mired in clouds, but there may be chances to spot the aurora through breaks in the clouds in Montana:
In Iceland – there’s a storm expected to blow through overnight. There will be a brief window where if may be clear in the early evening, but clouds are expected to roll in from the southwest to the north east. The best bet for Northern Lights in Iceland will be in the northeast, the earlier the lights start the better:
In the rest of europe – conditions look very good for most of the UK and Ireland. Scotland is predicted to have some cloud cover so it may take being flexible to find a good spot to photograph. In Norway, there could be some good views in the South, but most Scandinavian photographers will have to drive to find clear skies:
Update: 13:30UTC Feb 14 (8:30am EST)
So far, no signs that the CME is approaching on EPAM:
Typically when a CME is approaching, EPAM levels will rise slowly from the moment the eruption happens through the point that the CME shock arrives at Earth. If the EPAM isn’t rising, it can be an indication that the CME will pass by Earth without any impact. Sometimes when the CME is travelling slowly, the EPAM won’t rise until just a couple hours before the arrival. It is too early to call this storm.
Update: 00:30UTC Feb 14 (7:30pm EST 12/13)
A quick update on some of the imagery coming from the flare on 2/11. When the flare happened, there was a clear CME traveling to the north and west, but there was also a shock wave that moved eastward across the Sun showing “ripples” all the way to the coronal hole in the South West. When looking at the LASCO CME imaging, the second portion of the eruption signature shows a 3/4 partial halo. Finally, the coronal dimming is fairly extensive. All three of these together indicate there’s a good chance there is a CME headed toward Earth.
The New Year’s Aurora of 2016 is playing out as expected in the “slower CME, longer storm” forecast scenario. There have been a few periods of G1-G2 storming. Wing-KP was overestimating the Kp and calling for 7+ earlier in the day. About 2 hours ago, Bz shifted strongly to the south and it has been in the -15nT to -17nT range since. It’s likely that the Wing-Kp model is now underestimating the actual extend of the aurora. The next 1-4 hours could produce some very good aurora. It even look likes there may be some clearing around sunset for downeast Maine, if the storm lasts another 6 hours, the upper Midwest may see northern lights around sunset as well
UPDATE: 04:00UTC December 31
The CME arrived! It arrived shortly after the previous update. so far Solar wind speed have been in the 425-475 km/s range, which is fairly low for a CME. The Bz component of the magnetic field has switched a couple times between negative and positive. There was a 45 minute period of sustained south orientation that pushed the KP to 5, but it has since subsided. It’s likely there will be more periods of high KP over the coming hours. Here’s is what the ACE data looked at at the moment the CME first arrived:
There are a lot of articles being posted about the ongoing storm. NLN has started a live updated post that contains links to those articles.
UPDATE: 00:00UTC December 31
8 hours after the official forecasted arrival of the CME, it hasn’t arrived yet. Not to worry, it is still on it’s way.
As noted in the original post, this means that it’s more likely the NASA Enlil model is closer to correct than the SWPC model. That means a wider, slower moving CME. It will bring a slightly weaker storm with slower solar wind speeds, but it also should make for a longer duration storm. This will give aurora hunters on the west coast and in Australia/NewZealand a better chance. If the storm lasts long enough, some new year’s revelers in Europe, Iceland and the East coast of the United states could be ringing in the new year under a dancing sky. Here’s the updated forecast graphic from SWPC:
UPDATE: 03:00UTC December 30
As the watch period begins, SWPC has updated the storm watch to G3. This means that KP=7+ is expected. There have only been a couple storms of this magnitude during this solar cycle. The timing of the start of the storm has stayed the same, roughly around 3pm UTC (10:00am EST). The duration prediction was extended to 15 hours, which should give north american viewers a better chance of seeing northern lights.
EPAM will continue to rise as the CME approaches Earth. Once the shock hits, EPAM should spike up, then start to decline. When the CME arrives at the ACE satellite, watch the Bz, if it is negative, this storm could be really good. If the Bz stays positive, this storm could top out at just KP=5, so keep your fingers crossed.
Also keep an eye on the arrival time of the CME. The later it arrives the weaker the storm will be, but the longer it will last (because the CME was moving slower than expected.
Original Post: 06:00UTC December 29
The Earth-directed Coronal Mass Ejection (CME) from Monday’s long duration solar flare is predicted to arrive on December 20. The Space Weather Prediction Center has issued a G2 geomagnetic storm watch for Wednesday and a G1 watch for Thursday. Aurora hunters with clear skies should get a nice show. For clouded-in skywatchers, keep an eye on the NLN Twitter feed for images of the northern lights.
Monday’s M1.86 originated from active region 2473 (Beta-Delta), the same region that produced a couple M-class flares as it rotated onto the disk about a week ago. The region was beyond the center of the Earth-strike zone during for this eruption, but was close enough for a nice CME signature on LASCO. In the CACTus image below, see the partial halo ejection:
The two main models that are used to predict the timelines of the storm are in disagreement. The official forecast model shows a stronger faster moving storm arriving around noon eastern time and lasting 6-12 hours. The NASA model shows a slower moving storm, that would be weaker, arrive later and last longer. It will be exciting to see which model proves correct. Here is the current predicted timeline for the KP according to the SWPC models.
NLN will continue to post updates on the twitter feed as this storm progresses.