Northern Lights Now – A large coronal hole was pointed directly towards Earth on April 9th and 10th. The high speed solar wind from that exposed area is should impact Earth on April 13 and 14. Space weather forecasters are expecting two consecutive days of geomagnetic storming. That could bring several opportunities for Aurora hunters to experience the Northern and Southern Lights. Here’s an image from SDO from late on April 9 in AIA 211, a wavelength that makes it easy to see coronal holes:
SWPC is calling for two periods of active Aurora (G1 level storming). The first period is early on April 13 and the second is Early on April 14. For North American Aurora viewers this is in prime evening viewing time. Europeans viewers will have to stay up past midnight. See the NLN Aurora cast for April 13 and 14. The data behind this infographic comes from the Space Weather Prediction Center in Boulder Colorado
Note: It is not an error that both days have the same profile throughout the day. The is what the forecasting models have predicted.
Northern Lights Now – The Space Weather Prediction Center (SWPC) in Boulder, CO has issued a G1 Geomagnetic storm watch for April 2nd, 2016 indicating that there could be isolated periods of KP=5 aurora. This predicted activity is the result of a negative polarity coronal hole that was pointed towards Earth yesterday. The interplanetary magnetic field (IMF) is expected to be disturbed, and the higher speed winds from the coronal hole will likely be enough to disturb Earth’s magnetic fields.
The coronal hole responsible for the predicted activity produced a period of G3 storming on the previous rotation, but has changed structure and looks like it is unlikely that it will be as strong. Data from STEREO-A showed that this coronal hole still has a good chance of producing negative Bz at Earth as the high speed wind arrives. While the structure of the coronal hole has changed, there is still a possibility it could pack a punch. NLN would not be surprised if there is a brief period of G2 activity during the storming.
In addition, the coronal hole is located adjacent to Active Region 2526. While that region has been quiet, it still has the possibility of flaring. If it does flare, and the flare releases a CME, it will the impact at Earth will be enhanced by the coronal hole. The period where a flare from this region could erupt and impact Earth is only about 24 hours from now. As it has been quiet, and it lost magnetic complexity over the last 24 hours, This scenario remains a remote possibility. Keep an eye on this region.
The second coronal hole that is to the North and East of the initial CH has grown and become more defined over the past 24 hours. This CH could impact Earth late on the 3rd and on the 4th. If it continues to grow or there is activity on it’s permeter, it is possible that the G1 watch could be extended additional days.
As this storm develops and space weather forecasters know more NLN will keep the 3-day auroraCast updated.
SWPC has now issued a G1 geomagnetic storm watch for Saturday April 2nd.
Northern Lights Now – As March draws to a close, there are a couple areas on the Solar disk with notable activity. On Sunday, a stunning solar prominence on the East limb produced a show in SDO imagery. Today, an active region that grew from alpha to beta and is now pointed straight at Earth and located between two coronal holes. Both coronal holes are in negative polarity regions and are related to coronal holes that produced negative Bz and aurora during their previous rotation. It’s possible this could happen again, but likley to a lesser degree on the current rotation.
A solar prominence happens when a large area of gas and charged particles lifts off the Sun into the corona. Prominences are visible in the 304 Angstrom images available on the SDO website. When they happen on the limb they are spectacular, as the dark sky of space acts as a backdrop to the heated gasses lift off the surface. Here’s an animated GIF of images of the prominence as it erupted on Sunday on the east limb over a 12 hour period.
It is unlikely this feature will have any impact on Earth. If it did produce a CME during the eruption, it would be well to the East of the Earth-Sun line.
A Growing Beta Active Region
Active Region 2526 has been increasing in size (from 120MH to 200MH) as it rotates toward center disk. Tonight, SWPC upgraded the magnetic classification from Alpha to Beta. The changes to the region are minor but do increase the probability of flare activity slightly. Thus far, the active region has not produced much flare activity, but keep an eye on it, this could change.
A Pair of Coronal Holes
The most promising solar feature for aurora hunters is the coronal hole that was pointed at Earth yesterday. On it’s previous pass, this coronal hole was a complex of three separate holes and lead to a prolonged period of enhanced solar wind, several periods of south-oriented Bz and a phenomenal display of Aurora. The coronal hole structure has degraded since the last rotation and is now comprised of a pair of medium sized coronal holes. Until today, when the second hole emerged to the NE of the first, this single coronal hole might have produced a short period of elevated solar wind. Now that it is a pair, Earth could experience couple days of slightly elevated soalr wind. Even better news for aurora hunters is that active region 2526 is directly between these two coronal holes, so if it does flare and produce a CME, the plasma will be accelerated by the elevated wind speed. Again, these are worth keeping an eye on the next couple days.