Northern Lights Now – The large coronal hole that was pointed directly towards Earth on May 12th and 13th combined with recent solar disturbances prompted space weather forecasters to predict there will be an extended period of aurora activity the third week of May. The Space Weather Prediction Center (SWPC) issued storm watches for three consecutive days with a G1 watch posted for May 16, and G2 watches posted for both May 17 and 18. A G1 storm watch means KP values will likely exceed 4.67 during the 24 hour period, a G2 storm watch means the KP will likely exceed 5.67.
The coronal hole responsible for the expected activity stretched from North to South on the solar disk on May 13. In the image below, the coronal hole is the outlined darker area at the time it was directed towards Earth. High speed solar wind exiting from that region should arrive at Earth around May 16. As it arrives, expect solar wind speed readings from DSCOVR to increase, possibly to as high as 600 km/s. As the higher wind pushes on Earth’s magnetosphere, KP will read higher and any aurora will be stronger during periods of negative Bz.
After the initial coronal hole impact, there are two additional features that should impact Earth this week. Part two of this storm will be the arrival of a slow moving CME that launched from the southern hemisphere of the Sun on May 13. This CME is visible on LASCO C2 and C3 imagery, but it is faint. There is a decent chance it will miss Earth entirely to the south and we may see nothing from it. But it may also arrive at Earth as a glancing blow. This is a low confidence forecast, but if it does hit there could be G2 storming due the the magnetosphere already being activated by the initial coronal hole. Here’s an animatedGIF of the CME lauching as seen by LASCO C3:
Finally the third portion of this storm is most promising and is expected to impact Earth on 5/19 and 5/20. This second coronal hole produced great activity on the previous rotation in April. NLN will keep you updated with more information about this CH as it’s structure becomes evident.
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.
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:
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