Northern Lights Now – On July 16 NLN noted that there was a delta spot on active region 2567. The delta spot didn’t last long, but the active region interacted with AR 2565 to produce several C-class flares over the next 24-36 hours. Early on the 17th, between 5:39 and 9:27 UTC, there was a long duration C1 flare between the two with a period of coronal dimming. Coronal dimming is often a sign that a CME was launched – sure enough a large, but slow CME was launched AND the region was in the Earth strike zone. It get’s better, there is coronal hole pointed towards Earth that could enhance the incoming solar storm. Social media is abuzz with the prospect we might get a solar storm and an aurora show.
Not so fast! While the CME had an asymmetric halo signature, it was quite faint. It’s likely there was not a lot of material ejected. Subsequent WSA-Enlil model runs show a small impact from a slow moving CME early on July 21. The model indicate such a diffuse impact that SWPC has chosen not to post a storm watch. The max predicted KP is 4. In addition to that, the moon will be nearly full as a waning gibbous, so at best there will be an hour two of true dark just after sunset.
Bottom line – There is definitely a higher chance for aurora late on the 20th and early on the 21st than at other times. If the orientation of the CME is favorable, or if it is pushed faster than the models suggest by the high speed wind, we could easily see a period of G1 storming. This is a wait-and-see type event, have your cameras charged and ready just in case.
Northern Lights Now – Solar activity has been low over the last month, but a large coronal hole combined with some activity on it’s periphery is prompting SWPC to issue a G1 geomagnetic storm watch for July 7.
UPDATE 1:30AM GMT 7/7 (9:30PM EST July 6)
SWPC has updated today’s watch to include 7/8. We expected this was possible based on the size and location of the coronal hole. Keep an eye on the solar wind speed. Once it increases watch the Bz. If it points south, there’s a good chance for a show. The current predicted times for the storm are late on 7/7 and early on 7/8
There have only been about 20 sunspots recorded in June, and none so far in July. Without sunspots, solar flares and eruptions are less likely. This leave coronal holes and filament eruptions as the remaining potential sources for northern lights activity. Currently there is a large coronal hole pointed towards Earth:
This coronal hole should start to impact Earth midday July 6 with enhanced solar wind speeds through Early on July 7. The official forecast from SWPC shows only one period of G1 activity around 18:00GMT, but there’s reason to believe this could actually product more activity than that. First, these forecasts often miss by 6-12 hours, so the active period could happen any time during the day on the 6th or early on the 7th. Second, there was a minor filament eruption to the west of the coronal hole on the 4th of July. Check out the video linked in @haloCME’s post.
Northern Lights Now – NLN will be live blogging tonight’s expected G2 solar storm, please come back often for updates.
Update 11:00am UTC 6/6/2016 (7:00am EST)
Sure enough! There was another substorm left in this active period. KP reached G2 levels in the 3-6am UTC period, while the short term KP forecast actually briefly reaching G3. Northern lights reports streamed in from western New York through the upper Midwest on Twitter. As of this update, KP is still in the G1 range, but the Bz shifted decisively north, so it may be done for good now. Thanks live tracking this storm with NLN! Here are some of those Twitter posts:
The storm is winding down. Solar winds are still high, but proton density and Bt have decreased. Bz is not making sustained or deep moves in the negative direction. The storm had one brief period where the short term forecast reached G2 levels, but the max three-hour activity was measured at G1. The timing of this storm also did not align well for aurora hunters as there were clouds in most places that would have been visible. New Zealand was the big winner. There still a chance a good substorm could produce Aurora for hunters in the midwest or Central Canada over the next couple hours, but it is becoming less and less likely. Here’s the graph of storm activity from this storm showing 4 periods of G1:
The storm is still stirring! The Wing-KP model is now predicting KP=5.67 in 50 minutes. Solar wind speed are over 600 km/s and Bz is moving in and out of negative. If there is a sustained negative Bz, KP could shoot up into the G3 storming range. Best bet for aurora is Europe south of the “land of the midnight Sun.” Iceland won’t be getting dark enough for a show tonight, and it’s cloudy on the American East coast. If the storm lasts long enough hunters in the western great lakes and into the plains could get lucky.
Update 2:30pm UTC 6/5/2016 (11:30am EST)
Short term predictions now include KP=5.00 or G1 storming! Expect more aurora reports from the southern hemisphere soon!
Update 2:00pm UTC 6/5/2016 (11:00am EST)
Solar wind speeds are now reading above 500 km/s, the storm is arriving. It is arriving about 12 hours later than initially forecast, but it’s here. The timing is such that most of North America missed the first part of this storm. Our Kiwi and Aussie friends should get a good show though. If the storm continues on long enough, European aurora hunters may also get a treat. There have been a couple early Aurora reports from NZ. Here’s a back of cam picture of the beginning of the storm from Ian Griffin:
Bonkersly bright display of aurora Australis going on right now get off your buns Dunedinites and enjoy the show pic.twitter.com/tDeg4X09iE
Not much to report yet. Wind speeds over the lat hour climbed to as high as 390 km/s, but are still well off of the predicted speeds. In a hint of good news, Bz has been negative over the last hour. That negative Bz has helped push the predicted Bz to 4.33, it’s highest level of the storm. This shows that even with weak wind, a strong Bt and proton density plus a favorable Bz can be enough for aurora hunters. Stay tuned, the next 12 hours could be interesting.
Update 2:30am UTC 6/5/2016 (10:30pm EST)
Over the last three hours, the solar wind environment has started to reflect the influence of the coronal hole. Density has increased from around 3-4 parts per cubic centimeter to over 10, with spikes to 40+. The solar wind speed has increased slightly from ~300 km/s to 325-350 km/s. Over the next several hours, we’re expecting solar wind to gradually increase, it could reach as high as 600 km/s. Once the wind speed is higher, watch the Bz. If it shifts south, aurora should follow soon after. Here’s a graphic of the solar wind environment from the SWPC, note the distinct change in density profile and wind speed (labeled radial speed) around 23:00:
Update 9:30pm UTC 6/4/2016 (5:30pm EST)
The first hints that the solar storm may be arriving are showing in the ACE solar wind data. Proton density has slowly increased to 5 p/cm3 over the last 45 minutes, and took a sudden jump to 11 p/cm3 in the last 5 minutes. This was accompanied by an increase in Bt to 5 nT. It will still be several hours before there is any real chance for Aurora, but this is the first hint that activity may be picking up.