A filament eruption on the South West quadrant of the Sun launched a coronal mass ejection (CME) towards Earth on Wednesday 8/12. When it arrives it should produce aurora. SWPC has issued a G1 geomagnetic storm watch for Aug 16 with an expected peak at the beginning of the period. Here’s an animated GIF of the CME launching off the Sun:
This storm may arrive as a one-two punch. In addition the the CME related to the filament, forecasters are expecting an increase in solar wind and density from a coronal hole high speed stream. If these two arrive around the same time, they could create two peaks in activity, or they could generate a stronger aurora storm.
The WSA-ENLIL model is showing the increase in geomagnetic around the beginning of the Aug 16 time period. This corresponds to just before midnight on the 15th in Europe, around sunset on the 15th in North America and around midday on the 16th in Australia/New Zealand. As always these forecasts can by off by +/- 6-12 hours, so aurora hunters should be prepared to be out any time it is dark this weekend. Here’s the snapshot of the WSA-ENLIL model at the expected arrival time:
You can monitor the KP live on Northern Lights Now on our Live KP page. This shows the current KP and projected KP over the next 40-70 minutes. This should give an early warning that aurora may be visible.
SWPC has posted a G1 for late July 31 and early August 1, 2015. This watch is due to the arrival of a high speed solar wind stream coming from a group of coronal holes pointed towards Earth. The predicted peak of activity coincides almost directly with the second full Moon of July, a blue moon, which will make viewing aurora difficult unless this proves to be a very strong storm.
The three coronal holes that are contributing the predicted increase in solar wind speed are visible in the combined 211, 193 and 171 wavelengths from July 29. In this image taken by the SDO observatory NLN has added arrows pointing to the coronal holes that appear as dark areas.
Generally, increases in solar wind speed is are more predictable coming from coronal holes. They rotate with the Sun and so solar scientists have data from the previous rotation. Additionally, the flows out from a coronal hole are more consistent and even than in a solar flare. Together, these give forecasters higher than normal confidence in the models and predicted timeline. For this solar storm, SWPC is predicting KP=5, or G1 storming, in the final 3-hour period of 7/31, and the first 3-hour period of 8/1. This timeline translated to between 5PM to 11pm on July 31 central time.
This image shows the predicted 3-hour maximum KP values for the two days of the current storm watch (click image to enlarge)
The storm will coincide almost directly with the full Moon. This is the second full Moon of July making it the first Blue Moon since August 20, 2013. While that is neat and interesting, the full moon will brighten the entire sky and will make viewing this aurora difficult.
[Update: G1 storming is arriving Earlier than expected! KP=5.67 is predicted for 6:00pm EST]
SWPC has posted a G1 geomagnetic storm watch for July 5. There is a chance that KP will be higher than 5, between 8:00pm EST July 4th and 8pm EST July 5th. Maybe mother nature will put on a fireworks show for those of us celebrating Independence Day in the US.
We don’t have specifics details on the expected timing, but follow the NLN Twitter Feed for updates as we get more information from SWPC.
The enhanced chances for Aurora this weekend are due to a Coronal Hole High Speed Stream or CH HSS. In the image below, the dark area on the Sun (shaped a little like South America) is the coronal hole. This area spews a fast moving river of charged particles into space. When that stream is pointed towards Earth, it typically arrives about three days later.
When the activity from this storm picks up, don’t forget to watch the KP live on NLN’s live KP web page