Coronal Hole Prompts SWPC to Issue G1 Geomagnetic Strom Watch For January 6, 2016

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Northern Lights Now – The trend of busy space weather over the last two months continues tomorrow with a new geomagnetic storm watch issued for January 6, 2016. The watch, which means it’s possible space weather conditions may produce aurora, is due to an expected increase in ambient solar wind speeds. The source of the higher wind speed is a large transequitorial coronal hole that was pointed directly at Earth on January 3.

Coronal hole rotating into the Earth Strike zone prompts a new geomagnetic storm watch
Coronal hole rotating into the Earth Strike zone prompts a new geomagnetic storm watch

The current official forecast is only calling for a single 3-hour period of KP=5 for this storm, but there’s a prolonged period of KP=4 before and after the predicted peak period. That’s an unusually short period of activity for a coronal hole, and it may turn out to be an underestimate. It’s possible that at any point in the 15 hours before and after the predicted peak KP values could cross above minor storm thresholds. If any small CMEs are carried along the wind stream their impact can be magnified. Here is the SWPC forecast as of midnight GMT on Jan 5 as visualized by the NLN auroracast infographic:

NLN Auroracast shows one 3-hour period of KP=5 and 15 consecutive hours of KP=4
NLN AuroraCast shows one 3-hour period of KP=5 and 15 consecutive hours of KP=4

This is the second rotation for this coronal hole. On the last rotation it produced solar wind speeds around 650 km/s and two short periods of KP= 5.0 – 5.33. The coronal hole actually looks to have a slightly more defined signature in this rotation. Read NLN’s post about the last rotation here

Happy Hunting!

Brief G2 Aurora Storm Expected Tonight – January 3

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Update 22:00UTC January 3, 2016

It appears this #CME missed Earth and we won’t be getting an Aurora show tonight. From the beginning this was low confidence forecast. The CME’s signature was well South and West of the Earth-Sun line. If it was just a bit farther to the South or West, Earth would be untouched by the shock. It seems is what has happened. There is a slim, outside chance that it may still arrive, but with each passing hour it is less likely. Here is the output from the SWPC ENLIL model (How to read the ENLIL model) showing the predicted location of the CME:

ENLIL model shows the CME mostly South and West of Earth
ENLIL model shows the CME mostly South and West of Earth

Original Post: 03:00UTC January 3, 2016

Northern Lights Now – SWPC has issued a G2 geomagnetic storm watch for Sunday, January 3rd. Space weather forecasters are expecting a brief but strong storm as the Coronal Mass Ejection (CME) from a long duration solar flare passes Earth. It is expected to be a glancing blow as the plasma in the CME will pass mostly to the West and South of Earth. The predicted time of arrival of this fast moving CME:

Auroracast from NLN show the SWPC forecast of G2 storming from 4am to 10AM EST
Auroracast from NLN show the SWPC forecast of G2 storming from 4am to 10AM EST

What to expect:
As the edge of the plasma cloud passes Earth, proton levels will continue to rise as displayed on the EPAM. When the shock hits, they will jump then fall. About an hour later, magnetometers on Earth will register the passage of the shock. At that time, if the Bz component is south, there may be a short period of strong aurora. This CME is predicted to be mostly South and West of Earth, and could easily be too far away from Earth to make an impact as it passes, so this is a lower-than-normal confidence forecast.

This is the flare that produced the CME:

Animated GIF of the flare that cause the CME approaching Earth
Animated GIF of the flare that cause the CME approaching Earth

If you are planning on going out hunting tonight, remember to dress warmly. When you are standing still outside at night, you should dress for weather at least 20 degree colder than what is on the thermometer. Here’s a handy last minute guide to hunting aurora.

Stay tuned next week as coronal hole #44 may prompt SWPC to issue a new geomagnetic storm watch for January 5th and/or 6th.

Coronal hole rotating into the Earth Strike zone may prompt a new geomagnetic storm watch later this week
Coronal hole rotating into the Earth Strike zone may prompt a new geomagnetic storm watch later this week

Happy Hunting.