Northern Lights Now – The expected high speed solar wind that prompted a G1 geomagnetic watch for February 17 arrived early, but delivered G1 and G2 storming conditions. The wind was faster moving than expected, clocking in around 670 km/s. The fast wind combined with periods of Bz south was enough to excite Earth’s geomagnetic fields. At the time of this blog post, there were 18 hours of continuous G1 and G2 – KP greater than 4.67 and 5.67 respectively – storming recorded, followed by another quick burst. Here is a graph showing the official readings from SWPC Boulder:
While this was a fairly strong aurora storm, there were not many aurora reports. Most of the prime viewing locations were clouded in. An large storm system across Iceland and the British Isles, general overcast across much of Scandinavia, and an East coast ice and snow storm prevented the viewers in the prime locations from experiencing this show. However, aurora hunters in some locations were able to capture the show:
New Zealand was treated to a brief period of lights just before sunrise as the storm started. Both Paul Le Comte and Ian Griffin got out of bed to snap pictures near Dunedin:
Northern Lights Now – A second G1 geomagnetic storm watch for the week is posted for Wednesday offering the possibility of KP=5 or more. The increase in aurora borealis activity is expected as the high speed solar wind arrives from the northern extension of a southern pole coronal hole. Wind speed from the coronal hole approached 600km/s as it passed the STEREO-Ahead satellite, and it appears to have extended slightly northwards since the pass. It is possible wind speeds could reach 660 km/s at Earth by Wednesday. Here’s an image of the coronal hole when it was directed towards Earth:
The current forecast from SWPC calls for a 6 hour period of potential KP=5+ starting around 3:00PM GMT. Here is NLN’s AuroraCast inforgraphic of the expected Max KP’s
As always – these watches have a +/- of about 6 hours, and about a 50% accuracy, so hope for the best and plan for the worst.
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.