Tag Archives: geomagnetic storm watch

Pair of Solar Eruptions Prompts G2 Aurora watch for December 19, 2015

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UPDATE: 12/20/2015 2:40 PM EST

An amazing night of Aurora! It’s possible the two storms mentioned detailed in this post have merged together, producing a prolonged geomagnetic event. Storm levels have been at or above G1 (KP=5) for 15 hours. Bz has maintained a strong southward component. All signs point to another good night of aurora in northern Europe as far south as the Netherland and Germany. If you are planning to go out tonight, don’t forget the Last Minute Aurora Viewing Preparation Guide

15 hours of G1+G2 storming means many people will get to see aurora
15 hours of G1+G2 storming means many people will get to see aurora

UPDATE: 12/20/2015 1:30 AM EST

The Bz has shifted strongly south. Aurora reports are starting to come in. If the storms maintains it’s southward orientation, this is going to be a good storm.

UPDATE: 12/19/2015 10:40 PM EST

The CME has arrived at Earth. It arrived about 16 hours later than the earliest estimates. Now watch for the Bz orientation of the magnetic fields. If it stays negative, we could be in for an amazing show!

CME shock shown on space weather data charts from spaceweatherlive.com
CME shock shown on space weather data charts from spaceweatherlive.com

UPDATE: 12/18/2015 4:00 PM EST

EPAM is showing a clear rise in particles, the CME arrival is expected any moment now.

EPAM shows electron and Proton count rising as CME approaches
EPAM shows electron and Proton count rising as CME approaches

Original Post

Two eruptions on the Sun have unleashed a coronal mass ejection (CME) towards Earth. When it arrives it is expected to induce a G2 geomagnetic storm with the potential for aurora displays at mid-latitudes. The predicted timing of the arrival is good for Europe and excellent for North America. If it arrives on schedule, space weather predictions often are accurate within 3-6 hours, the northern lights show should start in Europe just before midnight, and it will be active as the Sun sets in the United States and Canada. It should last 6+ hours once it begins.

Imaging satellites in space, both ACE and SOHO, captured wonderful clear images of the eruptions. The explosions are so clear that anyone viewing them can easily identify the location and duration. In the video montage below, each view of the sun is campured through cameras with different lenses. Each sequence is roughly 80 images from SDO stitched together as a timelapse. The first, red, shows the eruptions at the 304 angstrom wavelength, followed by 335 angstroms (blue) and then 211 angstroms (purple). In each sequence the first eruptions is dead center and is from a C6.69 flare. The second is an elongated eruption to the South and East.

When flares like this occur, sometimes they eject hot plasma into space in the form of a CME. The LASCO camera aboard SOHO (Solar and Heliospheric Observatory) satellite is a specialized tool with an arm and disk in front of the lens designed to block the light coming directly from the Sun. This enables the camera to view the CME as light reflects off of it as it travels into space.

Both eruptions in the video above generated CMEs. The video below shows the raw image of the sun through lasco on the left, and then a black and white image of the difference between each set of frames coming from the those frames. The differential image makes the size and shape of the CME apparent. When the CME is mostly in one direction it means the CME is off the Earth sun line, but when the CME appears on all sides of the Sun, as is the case in this video, it indicates the CME is headed straight towards Earth. Space weather scientists can measure the speed of the CME from these images and use that estimate to predict when the CME will arrive at Earth.

What to Expect:

As of writing, the forecast is for aurora activity to begin at 21:00GMT on December 18th (4:00pm EST), and to increase over the following 6-9 hours. The NLN 3-day auroracast clock is updated two times per day, visit it for the most up-to-date forecast.

As the CME approached Earth, the first signs it is approaching will be that the EPAM rises – this happens because the approaching plasma in the CME is radiating electrons and protons. Once it arrives, the solar wind speed, the Bt and proton density, this data is available at spaceweatherlive.com, will show a sudden increase. When that happens, watch the Bz – if it is negative aurora hunters are in for a good show. Also watch the live KP. This is the best metric there is for knowing when aurora may be visible, it offers a 40-70 minute forecast. The higher the KP is the lower latitude the aurora will be visible. Here is the NLN auroracast at the time of this post:

NLN 3-day AuroraCast shows G2 storming for December 19th
NLN 3-day AuroraCast shows G2 storming for December 19th

Remember to read (and share on your social media networks!) the Last Minute Aurora Viewing Preparation Guide. This is a helpful how-to guide if you plan to go out and see the Aurora for yourself!

Happy Hunting!

Coronal Hole Prompts 48-Hour G1 Aurora Storm Watch December 6 2015

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UPDATE December 5, 2015: The G1 watch has been extended to 72 hours. This long duration event could produce aurora at almost any time over the next three days. Keep an eye on the KP to know when it may be possible to see northern lights in your area.

Original Post:
The expected high speed solar wind stream from a large Earth-directed coronal hole has prompted SWPC to issue a G1 geomagnetic storm watch for Sunday and Monday December 6 and 7. The coronal hole responsible for the watch, CH34, is one of three currently active coronal holes on the visible Solar disk at the moment. Coronal hole 34 is the nearly circular transequitorial dark area annotated with an orange outline on this AIA 211 image taken yesterday by SDO:

Coronal hole responsible for December 6 and 7 G1 geomagnetic storm watch
Coronal hole responsible for December 6 and 7 G1 geomagnetic storm watch

The other two coronal holes are visible in the same image. CH33 is the larger northern hemisphere dark area that has already moved past the Earth strike zone. CH35 is the long coronal hole to the South and East (to the right) of CH34. Coronal holes 34 and 35 almost appear to be merging into a single large big-dipper shaped coronal hole. You can see the demarcation clearly on the NOAA Solar Synoptic Map – coronal holes are outlined with a solid line with a hash to the inside of the coronal hole:

Synoptic Map shows Coronal Holes and active Regions
Synoptic Map shows Coronal Holes and active Regions

CH35’s extension to the north and west is responsible for second day of the extended watch. As both holes grow, there is a larger area of coronal hole pointed towards Earth for a longer time. The current 3-day forecast is calling for two 3-hour periods of KP=5 (G1 storming), with a long period of potential for G4 storming in the other times. If the Bz sets up correctly, this could turn into a long duration G1 or possibly G2 event, so stay tuned and keep an eye on the KP. Here’s the current 3-day Auroracast:

AuroraCast shows Das 2 and thee each with a period of expected KP=5
AuroraCast shows Das 2 and thee each with a period of expected KP=5

Happy Hunting!

M-Class Flare Promts G1 Aurora Storm Watch For November 11, 2015

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An coronal mass ejection (CME) that resulted from a surprise M3.95 solar flare launched a from the Sun on Monday has prompted the NOAA Space Weather Prediction Center (SWPC) to issue a G1 geomagnetic storm watch for Veterans day and November 12th. As the CME arrives at Earth, aurora hunters may be treated to a display of northern lights further south than normal.

NLN Aurora cast clock from SWPC 3-day forecast shows 15 hours of G1 storming forecast.
NLN AuroraCast clock from SWPC 3-day forecast shows 15 hours of G1 storming forecast.

A G1 storm watch means that the KP, a global scale of geomagnetic and aurora activity, may reach five out on it’s 0-9 range. As the KP rises higher, aurora borealis can be seen at lower latitudes. KP=5 indicates that the lights can be seen throughout Canada, along the northern boarder of the Continental United States, Northern Europe, and southern New Zealand.

KP is notoriously hard to predict, about 50% of the time a G1 watch is in effect, the KP does not actually rise to that level, but a G1 watch also means that the KP could easily rise higher than five. If you want to know the current KP readings, your best option is to monitor live KP trackers, such as Northern Lights Now’s current live KP chart, which give an accurate KP forecast 35-70 minutes in advance.

The flare that launched the CME was a surprise. It launched from active region 2449, which had a Beta magnetic structure. Typically, active regions need to have a “delta” sunspot in their group and be classified Beta-Delta or Beta-Delta-Gamma. Nonetheless, the solar flare that launched was spectactular. Here is an animated gif of the solar region while the flare was happening. Note that this is a zoomed in image, but that the several Earths could fit in the flare area.

The M3.95 flare from November 9 from SDO imagery
The M3.95 flare from November 9 from SDO imagery over a 12 hour period

When flares eruptions are long duration, like this one was, they can generate CMEs. A coronal mass ejection is a cloud of solar plasma that shoots from the Sun. When a CME is moving towards Earth, it typically arrives between 2 and 4 days later. As the plasma cloud passes earth, it disrupts the magenetosphere and sends charged particles into our upper atmosphere. It is the interaction of those particles with the gases in out atmosphere that cause the dancing northern lights. Don’t worry though! This storm won’t be strong enough to have any impact at Earth’s surface – just enjoy the show!

Happy Hunting