Tag Archives: CME

New Year’s 2016 Aurora Predicted – G3 Storming

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UPDATE: 20:00UTC December 31

The New Year’s Aurora of 2016 is playing out as expected in the “slower CME, longer storm” forecast scenario. There have been a few periods of G1-G2 storming. Wing-KP was overestimating the Kp and calling for 7+ earlier in the day. About 2 hours ago, Bz shifted strongly to the south and it has been in the -15nT to -17nT range since. It’s likely that the Wing-Kp model is now underestimating the actual extend of the aurora. The next 1-4 hours could produce some very good aurora. It even look likes there may be some clearing around sunset for downeast Maine, if the storm lasts another 6 hours, the upper Midwest may see northern lights around sunset as well

Some areas of clearing around sunset on the East Coast - might be able to see Aurora
Some areas of clearing around sunset on the East Coast – might be able to see Aurora

UPDATE: 04:00UTC December 31

The CME arrived! It arrived shortly after the previous update. so far Solar wind speed have been in the 425-475 km/s range, which is fairly low for a CME. The Bz component of the magnetic field has switched a couple times between negative and positive. There was a 45 minute period of sustained south orientation that pushed the KP to 5, but it has since subsided. It’s likely there will be more periods of high KP over the coming hours. Here’s is what the ACE data looked at at the moment the CME first arrived:

Bt Measured at the ACE satellite when the interplanetary shock hit.
Bt Measured at the ACE satellite when the interplanetary shock hit.

There are a lot of articles being posted about the ongoing storm. NLN has started a live updated post that contains links to those articles.

UPDATE: 00:00UTC December 31
8 hours after the official forecasted arrival of the CME, it hasn’t arrived yet. Not to worry, it is still on it’s way.

As noted in the original post, this means that it’s more likely the NASA Enlil model is closer to correct than the SWPC model. That means a wider, slower moving CME. It will bring a slightly weaker storm with slower solar wind speeds, but it also should make for a longer duration storm. This will give aurora hunters on the west coast and in Australia/NewZealand a better chance. If the storm lasts long enough, some new year’s revelers in Europe, Iceland and the East coast of the United states could be ringing in the new year under a dancing sky. Here’s the updated forecast graphic from SWPC:

Updated SWPC forecast shows G3 aurora extended to 12/31 and G1 into the new year
Updated SWPC forecast shows G3 aurora extended to 12/31 and G1 into the new year

UPDATE: 03:00UTC December 30

As the watch period begins, SWPC has updated the storm watch to G3. This means that KP=7+ is expected. There have only been a couple storms of this magnitude during this solar cycle. The timing of the start of the storm has stayed the same, roughly around 3pm UTC (10:00am EST). The duration prediction was extended to 15 hours, which should give north american viewers a better chance of seeing northern lights.

Three-day auroracast featuring day 1 with G3 storming predicted.
Three-day auroracast featuring day 1 with G3 storming predicted.

EPAM will continue to rise as the CME approaches Earth. Once the shock hits, EPAM should spike up, then start to decline. When the CME arrives at the ACE satellite, watch the Bz, if it is negative, this storm could be really good. If the Bz stays positive, this storm could top out at just KP=5, so keep your fingers crossed.

3-day EPAM graph shows a rise in electrons and protons measured at ACE as the CME approaches
3-day EPAM graph shows a rise in electrons and protons measured at ACE as the CME approaches

Also keep an eye on the arrival time of the CME. The later it arrives the weaker the storm will be, but the longer it will last (because the CME was moving slower than expected.

Original Post: 06:00UTC December 29

The Earth-directed Coronal Mass Ejection (CME) from Monday’s long duration solar flare is predicted to arrive on December 20. The Space Weather Prediction Center has issued a G2 geomagnetic storm watch for Wednesday and a G1 watch for Thursday. Aurora hunters with clear skies should get a nice show. For clouded-in skywatchers, keep an eye on the NLN Twitter feed for images of the northern lights.

Monday’s M1.86 originated from active region 2473 (Beta-Delta), the same region that produced a couple M-class flares as it rotated onto the disk about a week ago. The region was beyond the center of the Earth-strike zone during for this eruption, but was close enough for a nice CME signature on LASCO. In the CACTus image below, see the partial halo ejection:

Animated GIF from CACTus shows the partial halo CME signature from the 12/28 solar flare
Animated GIF from CACTus shows the partial halo CME signature from the 12/28 solar flare

The two main models that are used to predict the timelines of the storm are in disagreement. The official forecast model shows a stronger faster moving storm arriving around noon eastern time and lasting 6-12 hours. The NASA model shows a slower moving storm, that would be weaker, arrive later and last longer. It will be exciting to see which model proves correct. Here is the current predicted timeline for the KP according to the SWPC models.

Days Two and Three of the official max KP forecast from SWPC
Days Two and Three of the official max KP forecast from SWPC

NLN will continue to post updates on the twitter feed as this storm progresses.

Happy Hunting!

Winter Solstice 2015 Solar Storm Recap

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Northern Lights Now – On December 20th and 21st of 2015 the third largest geomagnetic storm of solar cycle 24 treated aurora hunters to 30 hours of dancing lights. The long duration of the storm gave nighttime photographers in North America two opportunities to see the northern lights through gaps in the clouds. Aurora reports on Twitter filled the NLN feed with images first from Wisconsin, then Alberta, Alaska, New Zealand, Northern Europe, Austria, Germany, England, Ireland, Iceland and then the North America again. Here is a chart of the official NOAA/SWPC recorded KP values from Boulder during the storm:

Boulder recorded 30 hours of G1-G2 storming during the winter solstice storm. of 2015
Boulder recorded 30 hours of G1-G2 storming during the winter solstice storm. of 2015

This solar storm started from two events on the Sun’s surface. The first was a long duration C6.69 flare at nearly dead center in the Earth strike zone. The second was a filament eruption to the south and east of the first eruption. Both events produced CMEs. Read more about the pair of eruptions NLN’s initial blog post on this storm.

Giants Causeway in Northern Ireland by Roy Smith Photo:

The CMEs from these two storms arrived later than initially predicted. Initial predictions were that the leading edge of the CME would reach Earth early in the day on December 19. The CME’s initial interplanetary shock was detected in ACE satellite data around 1520 GMT. Those 15 hours were time that many nighttime photographers wished they were sleeping instead!

Once they arrived, the two storms hit in sequence, not quite merging. As the storms played out, both had strongly negative Bz. Negative Bz is an aurora hunter’s dream. Once the field shifts south, a good show is sure to come – but we never know Bz until Earth is in the CME cloud. Space Weather scientists are still anticipate a long time before Bz can be accurately predicted in advance of a CME arrival. For now, forecasters assume arriving CMEs plasma clouds have a roughly 50/50 chance of being oriented with a Bz south.

In the Winter Solstice Storm of 2015, once the Bz shifted south, it stayed strongly south for 32 hours from 02:30GUTC on the 20th through 1030UTC on the 21st. During that time, the Bz deflection remained around -16 to -18 nT. Interestingly, after the initial shock, solar wind speeds stayed relatively low at below 450km/s for the duration of the storm. Had solar wind speeds been stronger, it’s possible that G3 level storming might have occurred. The slow wind speeds probably increased the duration of the storm (if the CME was moving faster, it would have completed it’s pass by Earth more quickly).

With a special shoutout to @VirtualAstro who helped surface some of these, here are some of our favorite images from this worldwide display of northern lights:

Swirls of green glow behind snow covered pine trees in Alaska by David W. Shaw

Green and yellow arches in the sky behind a church in Alberta by Célestine Aerden:

A string of pearls in the sky, technically called Auroral Beads, @Inukphysiker called this “lightsabors in the sky”

Another star wars reference came from Notanee Bourassa with this light-sabor aurora selfie

Team Tanner in Alberta often captures wonderful northern lights images, this anelic set was from Theresa (Tree) Tanner:

Finally, a stunning backdrop of purples and greens behind a solitary KW photography in Upstate New York:

Happy Hunting!