Aurora Possible July 20 and 21

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Northern Lights Now – There is a slight chance for an aurora display on July 20 and July 21 UTC. The most likely times are in the evening, just after sunset and before moonrise, across the Northern United States. The chances aurora may be visible are higher at this time because a cloud of magnetically charged gas is moving toward Earth after an eruption on the Sun on Sunday. The chances are only slight because the cloud is moving slowly and when it arrives it may not have enough magnetic charge to activate the aurora bands. It will also be hard to see any aurora because the Moon will be full or near-full, which will make the sky fairly bright overnight.

That said – keep your cameras ready because there’s a chance!

Happy Hunting

Will there be Northern Lights July 21?

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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.

Coronal dimming near center disk is a good indicator of a Earth-directed CME
Coronal dimming near center disk is a good indicator of a Earth-directed CME

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.

Happy Hunting

Aurora Activity Predicted for July 7

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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

Storm watch is extended to 7/8 as G1 periods are now expected on both 7/7 and 7/8
Storm watch is extended to 7/8 as G1 periods are now expected on both 7/7 and 7/8

Original Post

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:

Large coronal hole (#93) pointed towards Earth on  July 6.
Large coronal hole (#93) pointed towards Earth on July 6.

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.

In the video, the dimming indicates a potential eruption. If there is eruptive material from this features, it could excenuate any activity associated with the high speed wind.

Happy Hunting!