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G1 Aurora Predicted for November 29

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Northern Lights Now – The combination of an arriving CIR in advance of high speed winds from a coronal hole and a glancing blow CME from a November 25 eruption have prompted SWPC to post a G1 storm watch for November 29. This means aurora will be possible with KP values in excess of 5 predicted. The forecast, and activity sources, are a little complicated, so here is a breakdown.

G1 Storm Watch is posted for Nov 29
G1 Storm Watch is posted for Nov 29

First, the recurrent coronal hole (below) pointed towards Earth on Novemeber 25 is expected to bring moderately high speed solar winds. On the previous rotation, this same coronal hole brought winds of 425-450 km/s. Data from STEREO-A, which gets hit by the solar winds from a coronal hole about a week before Earth due to it’s location, indicate the CH is now producing winds in excess of 500 km/s. As such, it is reasonable to expect winds between 500 and 600 km/s.

Southern Hemisphere coronal hole should bring a CIR and Winds in excess of 500 km/s
Southern Hemisphere coronal hole should bring a CIR and Winds in excess of 500 km/s

The leading edge of the high speed winds is often turbulent. This region, known as the CIR, is expected to arrive early on Nov 29 and this is the time that the high speed winds are most likely to induce a burst of aurora.

In addition to the coronal hole, there was an eruption on November 25 that released a CME. The majority of the CME material was launched to the East and North of Earth, but some of the released plasma cloud is predicted to arrive at Earth as a glacing blow, also on Nov 29.

CME launches from the Sun - mostly to the East and North on Nov 25
CME launches from the Sun – mostly to the East and North on Nov 25

The WSA-Enlil model, below, shows the glancing blow. Notice the areas of lighter blue and green on the upper chart. These show the areas of plasma ejected in the CME as after it has traveled most of the way to Earth. Earth, the green dot, is on the very edge of that activity with a very wispy impact around 5AM UTC.

Wispy CME is modeled as a glancing blow in WSA-Enlil
Wispy CME is modeled as a glancing blow in WSA-Enlil

These two features make the forecast difficult. It is possible they could arrive around the same time and make for a pretty amazing G2 level storm. They could also not interact much and simply make two separate periods of G1 storming. Or, the CME could miss Earth entirely and the CIR could be too weak to induce much Aurora. This is a wait and see storm, so keep an eye on the data!

Happy Hunting!

Potential For G2/G3 Aurora July 16 and 17

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Northern Lights Now – A large, long duration M2.44 Solar flare launched an Earth-directed CME from the surface of the Sun early on July 14 that may make for a period of active aurora on July 16 and 17. The NOAA Space Weather Prediction Center (SWPC) has issued a G2 storm watch for both days indicating that the aurora activity readings could be as high as KP=5.67. There is a chance that this storm could reach G3 storm levels.

NLN will be activating an Aurora live blog over the next several days, so come back often for updates. For starters, here is a quick animation of the flare that generated the CME that will impact Earth.

Happy Hunting

Early March G2 Aurora Strom Puts on a Global Show

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Northern Lights Now – An extended period of high solar winds, the result of a large Earth-directed coronal hole, put on a three day long show for aurora hunters in high latitudes in early March. Photographers captured aurora glows, pillars, picket fences, dancing displays and illuminated night landscapes from around the world between mid March 1 through early March 4. Here’s a spectacular time lapse video from Adam Hill showing a wave of northern lights racing westward through the sky.

This extended storm was measured by the Space Weather Prediction Center (SWPC) as 9 periods of G1 storming and one period of G2 storming over 66 hours. G1 storming means the KP reached 4.67 and aurora can be visible as far south as Toronto, the upper midwest in the United States, Seattle and Scotland and can be seen as far north as Invercargill and Tasmania in the Southern Hemisphere. G2 storming means aurora can be seen at even lower latitudes near cities such as Portland, Boise, Dublin, Hamburg, Moscow and Christchurch. This chart show the first 5 days of March with the G1 and G2 3-hour periods showing in Red.

5 days of geomagnetic activity as measured by NOAA and SWPC
5 days of geomagnetic activity as measured by NOAA and SWPC

This early march storm is the result of a coronal hole that was pointed towards earth at the end of February. The hole is shown as a dark area on AIA 193 in the image below. It exposes the high speed solar wind emanating from the solar surface. Here’s an image of the coronal hole from the Solar Dynamics Observatory:

Coronal hole in AIA 193 shown as a dark finger reaching up toward center disk from the pole
Coronal hole in AIA 193 shown as a dark finger reaching up toward center disk from the pole

Those high speed solar winds take 2-5 days to arrive at Earth, and when they do they push on the magnetosphere and can cause aurora. This means that when there is a coronal hole pointed towards Earth solar scientists can predict that there is a good chance for activity 1-3 days in advance. Watch for those predictions on the NLN 3-day aurora cast – potential G1 storming shows as orange on those charts.

Let’s enjoy the view! Here are a few of our favorite tweets from this storm:

Watch the cloud clear and the lights come out to play in this time lapse

Stan’s take shows the aurora in black and white – this really brings out the texture and shapes

This panorama is worth clicking on and viewing full screen!

Finally, one of our favorite types of aurora – the “Picket Fence”

If you would like to have a chance to see the northern lights in person, consider following the NLN twitter feed (@northlightalert) to learn more about why aurora happen and when they may be visible.