Tag Archives: G1

Halloween Aurora 2021 – Live Blog – Day 2

Northern Lights Now – Thank you for visiting the Aurora live blog for the 2021 Halloween Aurora. Check back frequently as there are new updates for the current storm. This is the second day of the live blog. Find the previous day here

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NLN Live Blog Update – Saturday, October 31, 12:30 UTC (08:30 EST 10/31)
Live blog time: 14 Hours 15 mins

The CME arrived overnight while many on the East Coast US and Europe were asleep at about 09:30 GMT. The timing should be good for aurora hunters in Australia and New Zealand, Russia and possible northern Europe. When it arrived, the orientation was right for Aurora with a period of Bz North.

The CME arrived at about 09:30 GMT and was oriented with Bz South
The CME arrived at about 09:30 GMT and was oriented with Bz South

Given the data, Aurora Hunters should expect the KP to slowly increase. It is currently in the KP=4 range. If Bz stays negative, there should be G1 level storming soon.

NLN Live Blog Update – Saturday, October 31, 02:30 UTC (00:30 EST 10/31)
Live blog time: 6 Hours 15 mins

Happy Halloween to our EST hunters! The expected solar storm has not arrived yet. Solar wind data looks completely nominal. In fact, if you looked at only the solar wind data with 400 km/s and pretty flat data for Proton density, Bt and Bz over the last hour, you’d have no idea there was the potential for a storm.

Nominal data in the last hour at DSCOVR
Nominal data in the last hour at DSCOVR

But don’t give up yet. A quick peak at the EPAM at ACE shows that readings are still increasing. This often happens in advance of the arrival of a ICME shock. Note that they have been slowly rising since the X-class flare on the 29th. This isn’t over yet!

Solar Storm arrives with ICME impact early on October 12 GMT (live updates)

Northern Lights Now – The expected ICME has arrived. In the first hour since it arrived, solar wind data is indicating that is is oriented favorably to put on an aurora show.

Update: 16:00 GMT Oct 12, 2021:

What an amazing storm! The third phase of the storm arrived around 9:30 and had a strong (-14nT) southward component. With the atmosphere already primed from the first phase of the storm, aurora activity quickly elevated. Aurora sighting reports rolled in from all across northern North America. NLN will be doing storm recap later, but for now, enjoy this timelapse that shows all three phases of the storm from skunkbayweather.com

Update: 08:00 GMT on Oct 12, 2021:

It appears the second part of the CME is arriving, and Bz orientation is variable. It’s likely this means the storm is over for now.

Update: 07:00 GMT on Oct 12, 2021:

This has been a terrific storm. There has been an extended (6 hours now) period of moderate activity. Aurora reports have been coming in on Twitter from Iceland, Canada, New England (as far south as southern New Hampshire), the mid-west US and now Washington State and Alaska. Geomagnetic activity has reached G2, KP=6, levels as predicted by the SWPC.

The show looks like it will continue. Bz just dropped strongly south, so there should be another sub-storm over the next hour or two. We are expecting there will be aurora reports streaming in from hunters in New Zealand and Tasmania next.

After the current sub-storm, expect the core of the CME to arrive at earth. It is still impossible to forecast the orientation of the core of this storm. It is about a 50/50 tossup that it is oriented south and there is another 6-9 hours of activity, or that it is oriented north and the aurora ends. Keep an eye on the data and the orientation should reveal itself soon.

Original Post:

The shock arrived at the DSCOVR satellite around 1:45am GMT on October 12, 2021. At the time of impact, Solar wind speed jumped from 350km/s to almost 500 km/s. Proton density and BT also jumped in synchrony. Bz is always the wildcard. It is hard to know how the B component will be oriented until it arrives. Tonight, it arrived with a strong negative orientation. This is the most favorable setup for producing aurora.

In the image below, the upper chart is a proxy for hemispheric power and can be seen on the DSCOVR solar wind page. The more bars and the longer the bars the higher the likelihood of aurora. As time goes on, if the favorable conditions persist, the bars will continue to grow. In the lower part of the image, you can see when the ICME shock arrived with the big jump in solar wind data.

Favorable conditions for aurora seen early on October 12, 2021
Favorable conditions for aurora seen early on October 12, 2021

Happy hunting