Late September Features To Watch On The Sun

Share Button

Northern Lights Now – It has been two weeks since the X-class flare that active region 2673 released as it rotated out of view on the western limb. In that time space weather and aurora activity on Earth has been slowly waning. As that active region rotates back into view it will be renumbered, probably as 2682, and space weather forecasters will be watching to find out how it’s magnetic structure has changed. In addition to the returning active region, there are two coronal holes that may impact Earth’s Aurora activity over the next 7-10 days.

Coronal Holes

A small coronal hole was pointed towards Earth on Sept 21, 2017. Notice in the AIA 211 image below that the majority of the coronal hole is to the south of the solar equator. This time of year, the earth is actually about 7 degrees north of the solar equator. The size of this hole and it’s location to Earth’s south decreases the magnitude of anticipated impact. There is a slight chance for KP4 or KP5 on Sept 24 as the high speed wind from the hole travels near Earth, but SWPC has not issued a geomagnetic watch

Southern Coronal Hole pointed towards Earth on Sept 21
Southern Coronal Hole pointed towards Earth on Sept 21

A second, bigger, coronal hole is approaching the Earth strike zone and will likely have a bigger impact on Earth’s geomagnetic activity September 27th to 30th. This coronal is in the northern hemisphere and has a history of producing high solar wind speeds at Earth on it’s previous rotation. The hole has developed a southern “arm” that crosses the Solar equator. The hole is now “transequitorial,” another indication that Earth will likely be in the high speed wind stream. It seems likely this will prompt a G1 or possibly G2 storm watch later this week.

Another Coronal Hole is approaching the Earth Strike Zone. This one looks more likely to impact Earth's Space Weather
Another Coronal Hole is approaching the Earth Strike Zone. This one looks more likely to impact Earth’s Space Weather

The Return of AR 2673

The large complex active region that blasted 3 X-class flares and numerous M-class flares two weeks ago is completing it’s rotation around the back side of the Sun. While it was on the opposite side of the Sun, LASCO detected at least one major CME from it, but it his been less active over the last several days. As it rotates into view, forecasted will get their first glimpse of whether it has maintained it’s magnetic complexity.

We won’t know until 24-48 hours from now, but if it is still complex, there could be additional M-class flares over the next week. Stay tuned to find out!

Old AR 2673 is rotating into view
Old AR 2673 is rotating into view

Happy Hunting

Leave a Reply

Your email address will not be published. Required fields are marked *