NOAA SWPC has issued a G1 geomagnetic storm watch for Feb 28 and March 1 UTC. This means there is the possibility of KP=5 or greater between 7:00PM EST Friday night and 7:00pm EST Sunday night (midnight to midnight GMT).
This watch is posted due to the anticipated high speed solar wind related to the northward extension of the southern hemisphere coronal hole. It should look very familiar as this is the same coronal hole that produced a 4-day long period of enhanced Aurora activity at the end of January, see NLN’s writeup. Here’s an image of the Coronal hole as of right now:
On it’s last rotation, solar wind speeds at Earth reached 780km/s. NOAA is predicting similarly high winds this rotation. In addition to high wind speeds, this storm should start with a sector boundary crossing. During these boundary crossings, KP often becomes elevated. Stay tuned over the weekend!
For tonight’s featured tweets, something non-space related because Twitter filled with Llamas… yup, Llamas. Brian Wolven works at JHU applied Phsyics Lab with SSUSI. Today, he posted this most useful tweet in helping understand why Twitter is abuzz with Llamas and a dress:
Solar and sunspot activity this week has been between low and very low. In fact, right now there are only 4 sunspot groups and all are magnetically simple Beta groups. Together, they have only 23 sunspots. But, there has been plenty of interesting space weather.
A Large Back-sided CME Eruption and a Beautiful Prominence on the Sun
There were two powerful eruptions on the sun this week. The first was mostly south pointed and clearly back-sided. Because of it’s size and location, it will not have any impact on Earth. It is most likely from the very large filament we noted in the Nov 9 Aurora Brief. This filament held steady, and actually grew, while it was Earth-facing. It rotated off the Western Limb of the solar disk late last week. This filament likely lifted off the surface of the Sun creating the CME that is visible in the LASCO imagery in the video featured in “CMEs, Comet Captured In SOHO/LASCO Imagery 2/20/2015”
The Second CME launched this week was from the Southeast limb of the disk. When CMEs launch from the limb, imaging satellites can capture these eruptions with black space as a background. As a result images of these events are contrast rich and beautiful. Yesterday morning’s eruption produced this stunning image captured in AIA 304:
While this eruption was large, and was associated with a long duration C1 Flare, and displayed a CME on LASCO imagery, and produced an uptick in EPAM, Earth based Aurora watchers will be disappointed. The eruption was too far East and South of the Earth-Sun line to have an impact on our magtosphere. We’ll have to just admire the CME from afar. There should be even better images of this flare available in about 3 days.
Comet SOHO2875 Survives Solar Pass, May Be Visible From Earth
Early this week a comet was spotted in SOHO LASCO imagery, it was numbered then named SOHO2875 and C/2015 D1 (SOHO) respectively. Many Sun watchers first noticed it while viewing the large backsided CME from likely lifting filament. Watch the video closely, and you will see comet SOHO 2275 “sungraze” moving from upper right to lower left in the video we posted in this LASCO timelapse:
This comet is special for a couple reasons. First, it survived the close encounter with the Sun. It was within 1.1 million miles of the Sun, most comets that get this close break up or melt and turn to gas. Second, this comet is not part of the Kreutz Family – a group of comets that visit the sun about every 800 years and break into smaller comets on each pass. It is on a slightly different path that Kreutz comets making it unusual.
After surviving the pass, it developed a tail. There is a possibility that it may become visible in the evening sky over the next several weeks as it gets a little farther from the Sun. Many factors have to come together just right for the comet to be visible, but if it doesn’t break up, and the tail grows, and it continues to reflect enough light as it gets farther from the Sun it may appear in the evening sky near Venus and Mars as a magnitudte 6.5+ body. Keep an eye on your comet tracking apps as they update the track of this one!
G2 Storming from Coronal Hole Wind Stream Provide Great Aurora Viewing Opportunity
Finally, the coronal hole featured in February 24th’s Aurora Brief over-delivered on it’s promise of northern lights activity. KP reached 6 for a brief period just after midnight EST. Sky-watchers around the world uploaded many terrific pictures to the social media feeds we monitor.
Local (to NLN) Vermont photographer Brian Drourr captured a wonderful winterscape at Sand Bar State Park on Lake Champlain with yellows, greens and reds on the horizon. Brian is in the foreground of the photo standing on the frozen lake. It was -15 degrees at the time of the photo – it turned out to be the coldest night of the year. The tweet of his photo:
Another Photo of last night’s activity comes from Dave Patrick. He’s a dedicated Aurora chaser who completed an item on his bucket list with this photo. He captured both light pillars and aurora in the same image. Light pillars form when there are ice crystals in the air, and they reflect man made light from the ground in vertical beams. Light pillars are frequently mistaken for aurora, so it is a special treat to capture both in the same photograph. He says “I wanted to show natural versus man made aurora (light pillars are considered man-made aurora) in a single image of the dark night sky.” This was taken in Fergus, Ontario, Canada.
Finally, Paul Williams was lucky enough to be on a flight from London to New York on a Virgin Atlantic flight during the peak of the storm. This isn’t his first time catching Aurora on this route, so he knew to bring his camera and set up a time lapse. He titled his video “Curtains” and it is mesmerizing. You can see paul’s other pictures on Flickr. Here is “Curtains” on Youtube:
Sunspot activity has decreased. The main feature impacting Earth’s space weather has shifted from solar flares to coronal holes over the last month or so. Once again this week, we are seeing elevated solar winds as the result of a coronal hole high speed stream.
Solar winds picked up mid-yesterday and have been slowly increasing from 440km/s yesterday to over 500km/s as of this writing. There was a brief peak of winds over 550km/s. Two days ago, this small coronal hole was pointed directly at Earth:
High solar winds make our geomagnetosphere more susceptible to the impacts of solar disturbances. Any high proton flux or high density have the potential to activate aurora as reflected by higher KP. Late on the 23rd, and so far early on the 24th, KP values have already increased to 4. If Bz stays south for an extended period of time, the wing-KP model will likely register higher values.
Even without sunspots, we’ll take the Aurora activity. Here’s a great Aurora shot in today’s featured tweet, shared by Sun Viewer @SunViewer (who does an awesome job curating really nice Aurora photos!):