Northern Lights Now – It has been such a treat attending the Space Weather Workshop in Boulder Colorado. It is exciting to watch the ideas and collaboration arise as this wonderful community of academic, government, commercial, and enthusiast space weather stakeholders collaborate.
As I’ve been talking with people and explaining NLN, I’ve realized that I need to have a simple central place to access some of the more scicom-ready data visualizations, stories, videos, and just plain cool examples as a jumping off point. This blog entry is that.
Northern Lights Now – Space weather forecasters are predicting a period of G1 and G2 aurora conditions March 23rd and 24th. NLN is activating the live blog. We’ll aim to update a
couple times a day, or as warranted, so check back often.
NLN Live Blog Update – Monday, March 25, 11:30 UTC (07:30 EST 3/25)
Live Blog Time: 43hrs 0mins
Live Blog closed. Thanks y’all! It was wonderful watching this storm and aurora hunting with you.
In the end for forecast wasn’t a total bomb. The CME did arrive, but 36 hours late and far weaker than forecast. The Space Weather Forecasting community will be working together to see how models can be improved, but the short answer is “we need more data.” Space Weather forecasting is where land based meteorology was in the 60s and 70s. It will get better.
This site, the Twitter feed and the FB page all saw record traffic. Your interest and excitement about space weather helps make forecasts better in the long run as it raises awareness of space weather. As we look ahead, we’re expecting some very minor activity as a result of a coronal hole later this week. After that we’ll keep an eye out for new coronal holes and wait for solar minimum to pass. By late 2020 storms like this weekend will be more common again.
Oddly, even though max KP on this storm was just 2, there was a brief period around 6am UTC that yielded some aurora. There must have been a brief and localized disturbance that made this possible. We’ll leave you with these two photos from Isaac from Copper Harbor, MI
NLN Live Blog Update – Monday, March 25, 01:45 UTC (22:45 EST 3/24)
Live Blog Time: 33hrs 15mins
Live blog is now active longer than anticipated. This update: not much to see.
We are still in the ICME wind field. Over the last hour Bz has been variable with a max negative deflection around -5nT. Bz needs to be sustained negative for there to be a chance of KP reaching the 4-5 zone. KP has reflected the activity and reached KP=2.
NLN Live Blog Update – Sunday, March 24, 23:45 UTC (19:45 EST 3/24)
Live Blog Time: 31hrs 15mins
Exciting times! The forecast was not a total bust, we are clearly in the mist of the ICME now. We just saw a second major shift in solar wind data with temperature, By and Phy shifting. During the time between the initial onset and this second shift Earth was in the sheath of the CME. As we enter the next phase, wind speed should now pick up and we may see a change in Bz as we enter the core. Keep your fingers crossed for Bt to increase and Bz to shift into a more favorable orientation.
Because this storm is moving so slowly, we get a nice opportunity to watch it unfold and do analysis in real time. What would take 20 mins in another CME event is taking 40-90 in this one. That also means that if it does shift Bz south for the core of the CME we could have a long duration event which would push KP up to 4-5 and possibly 6.
Here’s the recent shift from ACE data:
NLN Live Blog Update – Sunday, March 24, 21:00 UTC (17:00 EST 3/24)
Live Blog Time: 27hrs 30mins
CME shock arrival is now visible in DSCOVR data.
For aurora hunters, the next thing you are looking for is where Bz will settle and how high the solar wind goes. For there to be any chance at G1 storming, wind speed will need to increase to above 500 km/s and Bz will need to be negative for at least 45 minutes.
Note: There are two bugs on the wind speed page that this storm has helped uncover. Won’t fix until later this week – sorry.
2) Occasionally the proton density bars in the top chart don’t actually display – the data in those charts is refreshed every 2 mins, it’ll come back.
NLN Live Blog Update – Sunday, March 24, 20:45 UTC (16:45 EST 3/24)
Live Blog Time: 27hrs 15mins
Better late than never. The CME arrived! Data from ACE is showing the arrival of the CME with Density, Temp and Wind Speed all jumping. Interestingly, it isn’t showing on DSCOVR data yet. Kudos to anyone who waited it out. We’ll watch for the next 90 mins to see if it will make any aurora, but initial signs show it won’t.
NLN Live Blog Update – Sunday, March 24, 18:00 UTC (14:00 EST 3/24)
Live Blog Time: 24hrs 30mins
This storm refuses to flash the sign that it’s over. As mentioned in the previous update, proton density is still hinting at unusual activity. It has now been above 10 p/cm^3 for over two hours. This makes for the biggest bar yet on the solar wind charts. That chart is designed so that the more bars there are, and the bigger they are, the more likely aurora is.
Still not shutting down the live blog. Tired yet?!
NLN Live Blog Update – Sunday, March 24, 15:15 UTC (11:15 EST 3/24)
Live Blog Time: 22hrs 45mins
For those still following this storm. We are not quite ready to close out this live blog. Notice the proton density – it is slowly creeping up. There’s an outside chance this could still be in advance of the CME shock arrival.
NLN Live Blog Update – Sunday, March 24, 06:15 UTC (02:15 EST 3/24)
Live Blog Time: 13hrs 45mins
Looks like scenario 3 from below.
Of course now that this event is called over, the CME will arrive – just to be fickle. If it does we’ll write about it tomorrow morning. Will wait to close out the live blog to tomorrow as well.
Calling it. Gotta get some sleep.
Still a slight chance the CME arrives in the next 6 hours. It likely missed to the west. Ahh – solar minimum.
Hope you enjoyed the anticipation and, if you went out, the stars and Moon.
NLN Live Blog Update – Sunday, March 24, 05:30 UTC (01:30 EST 3/24)
Live Blog Time: 13hrs 0mins
First hints that there is a change in the solar wind data. Bz has been north for the last 18 hours. In the last 20 minutes, it shifted to a south orientation. It is hard to interpret this in real time or until there is more data. It could mean:
1) There’s just a natural shift in the orientation of the magnetic clouds. The long sustained period of Bz north is an artifact of the slow solar wind so that section of plasma just took a long time to pass. That would mean no aurora.
2) We’re actually in the CME now and it is just FAR weaker than expected. This Bz shift would be as the main body of the CME is passing earth. If this is the case, Bz should slowly continue to shift south over the next several hours. But it won’t become very deep south. Still no aurora.
3) The CME just passed Earth, far to the west. The models missed the placement of the CME or got a bad read on the initial halos from STEREO-A and LASCO. Still no aurora.
4) This is the first hint that we’re about to get hit. If this is the case, the CME shock will probably happen in the next 90 minutes or so. When it does, Proton density and Bt will make sudden shifts, Wind speed will increase and BZ will either dive south or back north. We might get aurora if it dives south.
Hmmm — which are you routing for?
Here’s that Bz shift:
NLN Live Blog Update – Sunday, March 24, 02:00 UTC (22:00 EST 3/23)
Live Blog Time: 9hrs 30mins
Not so much of an update, but wanted to share this thought from @spaceWxMike
Solar wind speed usually doesn’t dip below 300, certainly has occurred but I’m thinking the way to describe this is the CME is causing a traffic jam which is why wind speeds have dipped so low. Remember, any forecast that verifies +/- 12 hours is a great SpaceWx forecast! ?
The idea of there being a traffic jam behind the incoming CME is interesting. This would be like a “calm before the storm” or water receding in advance of tsunami. It’s also like the ripples that form in water streaming down pavement on a hill. If the wind is getting “stopped up” behind the CME, we’ll know it when the CME arrives with a big short spike in wind speed.
Good fodder for optimists tonight.
NLN Live Blog Update – Sunday, March 24, 01:00 UTC (21:00 EST 3/23)
Live Blog Time: 8hrs 30mins
So much hype! NLN is seeing record traffic to our site (thanks y’all), but there is no sign of this storm yet. The later the CME arrives, the lower the wind speed will be when it gets here. At this point, G2 storming is still possible, but unlikely. Without a clear CME shock signal in the solar wind data we’re still at least 90 minutes out from any activity.
On the East coast, the Moon will be coming up in about an hour and a half. Did you know: The moon rises about 40 minutes later every night? It rises at sunset during a full moon. If it rises after sunset but in the evening, you know it is in it’s waning phase. Here’s roughly what tonight’s moon should look like
NLN Live Blog Update – Saturday, March 23, 21:30 UTC (17:30 EST 3/23)
Live Blog Time: 5hrs 0mins
Still nothing yet. Solar wind activity is showing no hint of the arrival of the expected CME. This is the time when aurora hunters start doubting themselves, forecasters, and all the other people out hunting with them. Remember it is always possible that we’ll get nothing – Space Weather Prediction is a new science. That said, it’s too early to call it. Hang tight hunters!
As you await the storm, you can watch the solar wind data. You might want to zoom out to 3 hours or 6 hours. As it approaches, Proton density and Bt will rise. When the CME hits, all four metrics will jump. From that point there’ll still be another 45-90 minutes before we see aurora.
NLN Live Blog Update – Saturday, March 23, 16:30 UTC (12:30 EST 3/23)
Live blog time: 0min
We are activating the live blog. So far there is no activity indicated in solar wind, so we remain in wait and see mode. The initial CME shock was modeled to arrive around noon UTC, so it is a little late but still well within normal +/-. This should be good news for hunters in the Europe, Iceland and North America as it makes it more likely the expected period of G2 will arrive once it’s dark.
Northern Lights Now – At Solar minimum, solar flares and active regions are infrequent, but they still happen. Active Region 2734 provides a case in point with a C1.3 solar flare eruption on March 8th that produced an earth-directed CME. As that CME arrives, aurora hunters can expect a chance for storming on March 11, and so SWPC has issued a G1 geomagnetic storm watch.
This flare had a strong “dimming” signature which is indicative of coronal propagation and a CME. What does that mean? Imagine blowing up an M-80 above the surface of a pond, you would see ripples moving out across the surface of the pond. Now imagine that the pond is boiling, you’d need a big M-80 (or a stick of dynamite!) to make ripples big enough to cross the surface. The image below shows the ripples from the flare explosion propagating across the surface of the Sun. Each frame is generated by subtracting one frame from the next, light areas show where there has been a change in brightness – or where the ripple arrived.
Notice that the ripples move out from the eruptive source in multiple directions. Because the eruption sent energy in all directions across the Sun, forecasters can assume energy was also sent off the surface of the Sun and towards Earth. This indicates the the flare was eruptive and sent a Coronal Mass Ejection (CME) into space away from the Sun and towards Earth.
The speed estimates show that the shock wave from this CME should arrive at Earth around midday on March 11 – that translates to early afternoon in Europe, late morning in the US and pre-sunrise in Australia and NZ. As a result, the forecast is for a period of G1 storming in the second half of the day. A C-class flare, even a very eruptive one, isn’t huge so the so the storming is expected to wane by early on the 12th.
Harder to Predict than Coronal Holes
Regular readers have become used to most activity recently being from coronal holes. The profile of a CME from a flare is different so we can expect a different kind of forecast. Coronal holes are fairly stable and rotate predictably with the Sun. They often last multiple rotations so Space Weather Forecasters can use data from previous rotations and from STEREO-A to make fairly detailed predictions. Solar flares are different, they happen at a point source on the Sun and the CME from each flare is oriented differently. Forecasters can make estimates of the speed of an ejection and the size, but knowing the orientation is still nearly impossible with current data.
The impact at Earth is also very different between Coronal Holes and CMEs. CH events have a distinctive signature which plays out slowly, sometimes over days, and often matches what was recorded on STEREO-A. CMEs hit with a shock, data shows a spike in solar wind speed and proton density then Bz and Bt can be used to determine the orientation of the storm. Sometimes the CME is oriented such that Bz dives deeply south for the duration of the storm providing aurora hunters a treat, sometimes is pegs north and aurora hunters get a no-show. It total though a CME related storm tends to be stronger than a coronal hole sourced storm, so forecasts will reflect a stronger storm, but it is more likely that there will be a no show. That can be frustrating for anyone who wants to plan on space weather events.