Low Confidence in August 16, 2016 G1 Geomagnetic Watch

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Northern Lights Now – SWPC has posted a G1 geomagnetic storm watch for August 16, 2016. This means there’s the potential for aurora as Kp values could reach 5+. However, this watch comes with a caveat that it is a low confidence forecast. The forecast discussion says:

Observations from STEREO-A
revealed a solar wind speed approaching 700 km/s and Bz decreasing to -10 to -15 nT with onset, although STEREOs position differs from Earths position by about 13 degrees relative to the ecliptic.

coronal hole high speed stream is expected to become geoeffective late on 15 Aug to early on 16 Aug, although there is a chance it may pass south of the ecliptic without interacting with Earth, as WSA-Enlil suggests. At this time, confidence in the model solution is not high enough to exclude the possibility of geoeffectiveness, so the geospace forecast reflects the high speed stream influence.

So what he heck does that mean? Let’s break it down.

First the good potential news: The coronal hole is on the surface of the Sun, and as the Sun rotates, the coronal hole co-rotates. In the diagram below, this means the coronal hole high speed wind will impact the planets and satellites in a counter clockwise direction. First Earth, then B, then A then 27 days later Earth again. From the Earth’s perspective it takes 27 days for the Sun to make a complete rotation. In the diagram A and B are satellites that are designed to capture “backside” views and data from the Sun. They are called STEREO-ahead and STEREO-behind.

Current locations of STEREO Ahead and Behind
Current locations of STEREO Ahead and Behind

With these satellites, heliophysicists capture data that can be used to predict the impact of the coronal hole when it rotates towards Earth. On it’s pass by these satellites about 14 days ago, the wind stream had a strong Bz component and wind speeds of 700 km/s. Together those two factors should be enough to put on a good show.

Why the low confidence?

Take a look at the coronal hole responsible below. Notice that it is centered in the southern hemisphere of the Sun. This means it is very possible that the high speed wind will to pass to the South of Earth.

Southern Hemisphere Coronal hole imaged on August 12, 2016 by SDO
Southern Hemisphere Coronal hole imaged on August 12, 2016 by SDO

Further, the current position of the STEREO satellites puts them in a different plane than the Earth’s orbit by 13 degrees. This also means it is possible that they could be registering just the northernmost part of the CH HSS. Again, this indicates the high speed winds may go to our south.

The final comment in that discussion, “At this time, confidence in the model solution is not high enough to exclude the possibility of geoeffectiveness, so the geospace forecast reflects the high speed stream influence,” means the forecasters don’t have enough data to exclude the possibility that this may hit Earth. Keep an eye on the data! If Earth is in line for this high speed stream, and Bz stays strongly negative, aurora hunters could be in for a show. To reflect this, the NLN AuroraCast is showing the period of potential G1 storming right at the beginning of Aug 16:

G1 storming predicted in AuroraCast in the first period of August 16
G1 storming predicted in AuroraCast in the first period of August 16

Happy Hunting!

Perseid Meteor Shower Peaks August 11-13

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Northern Lights Now – All eyes are on the sky tonight, tomorrow night and Saturday night as the annual Perseid meteor shower peaks. This year should be particularly exciting with rates of shooting stars potentially as high as 180-200 per hour or about one every 20 seconds. The best time to watch the show is between midnight and sunrise. The smallest, dimmest streaks will be easier to see once the quarter moon sets just after midnight.

This shower happens every year as Earth travels through the dust and debris that comet Swift-Tuttle leaves behind. Each time that comet passes through Earth’s orbit it leaves a new ribbon of shooting star material. That trail gets pushed around in space by the gravity of Jupiter. Astronomers have models that track those ribbons over time. This year, three separate groups of debris converge, so instead of the normal 60-100 meteors per hour, there could be as many as 180-200.

Of course, you won’t see any shooting stars if it is cloudy. The following maps show expected viewing conditions over the next two nights. It looks great for the West, but if you are in the North East or Mississippi Valley you might want to consider going out tonight since it will be cloudy tomorrow night.

Thursday Perseid viewing conditions  in the United States
Thursday Perseid viewing conditions in the United States
Friday Perseid viewing conditions  in the United States
Friday Perseid viewing conditions in the United States

We’d love to see your pictures of shooting stars! Send them our way via twitter (@northLightAlert)

Happy Hunting!

August 2nd & 3rd Solar Storm Live Blog

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Northern Lights Now – SWPC has posted a G2 storm watch for August 2nd and a G1 storm watch for August 3rd. NLN will keep a live blog of the storm as it unfolds here.

Update 8/4 2:30 UTC (10:30pm EST)

A quick recap: The big winners for aurora photography in this storm were the Northern states west of the Great Lakes and Canada, New Zealand and Tasmania. Denmark was also in the sweet spot at the very beginning of the storm when the initial CME arrived. There were a couple pictures of faint pillars in ME, NH and VT as well.

Solar wind never quite reached the high levels expected in the prediction. The helps explain why the storming started a little later than predicted also – if the wind is moving slower, it takes longer to travel from the Sun to Earth. In the end there were four periods of G1 storming recorded.

Thanks for following along for this storm!

This solar storm is done, in total 4 periods of G1, and 4 periods of KP=4. 24 hours total.
This solar storm is done, in total 4 periods of G1, and 4 periods of KP=4. 24 hours total.

Update 8/3 16:30 UTC (12:30pm EST)

The storm seem be dying down. Solar wind speeds have picked up, but they did not reach the predicted 600+ km/s. Here’s a create timelapse video from overnight from Robert Snache (@spirithands)

Update 8/3 11:00 UTC (7:00am EST)

So many wonderful pictures overnight. There were 3 periods of G1 recorded, and it appears there is a 4th happening now. There is an outside chance that the current period will reach G2. Here are a couple tweet with aurora pictures the we’ve seen overnight:

Back of cam:

Angel Brise finds some gems on webcams:

In Regina:

Neil Zeller:

Update 8/3 04:45 UTC (12:45am EST)

Starting about an hour ago, Bz dipped back south. Bt is still very strong, so this may be enough to produce some more pillars in the mid-latitudes. Aurora hunters will still probably need long exposures to get a good view. KP=5.33 (G1) in 20 minutes. Here’s a look at the boulder KP 3-hour averages so far – notice that storming didn’t technically reach G2 levels during the last substorm:

Two periods of storming so far in this solar storm
Two periods of storming so far in this solar storm

Update 8/2 23:00 UTC (7:00pm EST)

G2 storming is now predicted by the Wing-KP model. KP=6 shortly! This is almost exactly when the initial forecasts indicated we might see G2 storming. The strong solar wind hasn’t really picked up yet – wind speeds have only just touched 450 km/s.

Wing-KP shows KP=6 soon on August 2
Wing-KP shows KP=6 soon on August 2

Bz shifted to the north, so NLN is expecting this storm to be short lived. Good luck. Hopefully there will be more later tonight

Update 8/2 22:30 UTC (6:30pm EST)

First aurora picture of the night! This tweet shows a photo from Denmark by Twitter follower @ADphotography24

Update 8/2 21:45 UTC (5:45pm EST)

Around 8:00am UTC Bz made a decisive shift to the south. This should be good for aurora hunters and we expect to see some pictures coming in soon. We also expect the wing-KP models to reflect this aurora within the next 2-3 hrs.

Update 8/2 06:30 UPC (2:30am EST)

The first hints of the expected solar storm from the filament eruption appear to be arriving. Solar wind, density and Bt/Bz all reflected the shocks impact. The shock was weaker than expected, but also a little earlier than expected. We’re not really expecting any aurora yet, still plenty of hours ahead for a show.

Initial CME arrives around 04:00 UTC on August 2
Initial CME arrives around 04:00 UTC on August 2