Tag Archives: CME

G1 Storm Watch Posted for November 8

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Update 0330 GMT – 10:30pm EST

It appears the CME missed Earth, probably to the West and North. It is unlikely at this point there will be any aurora storming tonight.

Original Post
Northern Lights Now – The CME from the November 5 filament eruption is now expected to arrive at Earth late on Nov 8 and produce G1 storming. SWPC has issued a G1 geomagnetic storm watch. This forecast is lower confidence and more variable than usual. The current predicted timing shows that the period of KP=5 or higher is likely to happen at the end of the UTC day (or just after sunset on the US East coast and around midnight in Europe)

NLN AuroraCast shows the aurora forecast for potential G1 storming at the end of Nov 8 UTC
NLN AuroraCast shows the aurora forecast for potential G1 storming at the end of Nov 8 UTC

This forecast is low confidence because the majority of the CME is likely to go to the north and west of Earth. If Earth is hit, it will likely be a glancing blow. Further, it is impossible to predict the orientation of the cloud of plasma. If it happens to be oriented with a strong Bz south component, the KP could reach values higher the G1. If it is oriented with a strong positive Bz component, it’s unlikely KP values will read higher than 3 or 4. This is a classic wait-and-see storm.

Here is the WSA-Enlil model output from SWPC. It shows that when the CME arrives, it is likely to have a high proton density. This high proton density, at the same time as increasing solar wind are the primary motivations for issuing the G1 watch (click image for full size):

WSA-Enlil model shows CME arriving midday on Nov 8
WSA-Enlil model shows CME arriving midday on Nov 8

Happy Hunting!

G1 Aurora Predicted for October 13 and 14

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Northern Lights Now – A small filament eruption on October 9 released a CME that is approaching Earth. It should arrive late on the 13th or early on the 14th. This CME plus a high speed stream will combine to induce aurora storming that may reach G1 levels. The means that KP is predicted to be at or above 5.00. Here is the current predicted timing from SWPC:

6 hours of G1 level storming predicted on October 13 and 14 in the AuroraCast infographic
6 hours of G1 level storming predicted on October 13 and 14 in the AuroraCast infographic

This storm is lower confidence that some other recent storms. The filament eruption was at a very northern solar latitude. Normally an eruption at this latitude would be well north of the Earth-Sun line. This one may also be off the Earth Sun line. At around the same time as the filament eruption, shown below, there was also a back-sided eruption. The partial halo CME that was visible from the back-sided eruption may have confused the models as they project the speed and path of the earth-facing CME. This will be a “wait and see” type storm. Here’s that filament eruption in AIA 193 SDO imagery:

Filament eruption is visible in this AIA 193 SDO imagery in he northeast quadrent of the solar disk
Filament eruption is visible in this AIA 193 SDO imagery in he northeast quadrent of the solar disk

Happy Hunting!

G2 Aurora storming predicted for August 2nd and August 3rd 2016

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Northern Lights Now – SWPC has issued two geomagnetic storm watches for G2 storming (KP=6+) on August 2nd and G1 storming (KP=5+) on August 3rd. These watches are the result of a pair of solar features that will impact Earth starting midday UTC on August 2nd. The NLN AuroraCast shows the current predicted timing for the timing. As always, these can be within +/- 6 hours:

Please visit NLN’s live blog of this storm and follow out Twitter feed for the most up-to-date information.

NLN AuroraCast shows the expected timing of the G1 and G2 storming for Aug 2nd and 3rd
NLN AuroraCast shows the expected timing of the G1 and G2 storming for Aug 2nd and 3rd

The first solar event that will impact Earth is the arrival of a very slow moving CME (Coronal Mass Ejection) that was launched during the July 28th filament eruption. The eruption happened almost dead center (near N01E06) on the solar disk. The associated CME was estimated to be travelling at 125-150 km/s. At that speed, it could take as many as 7 days for the CME to arrive at Earth, but it should be pushed by the ambient solar wind to 350 km/s or so. Then, an even higher wind from a coronal hole high speed wind stream should push it even faster to 600-650 km/s. There are several factors making the timing on this forecast complex – current models show the CME arriving midday to late August 2nd, 5 days after it’s launch.

In the animated GIF below watch the filament eruption in a composite of AIA 211, 193 and 171 wavelengths. These frames are about 14 hours of images taken by the Solar Dynamic Observatory (SDO) cameras. Note that just to the east (left) of the eruption, the coronal hole rotating into center disk is visible as a darker area:

AnimatedGIF of July 28th filament eruption responsible for the G2 aurora watch on Aug 2
AnimatedGIF of July 28th filament eruption responsible for the G2 aurora watch on Aug 2

The second feature is a large coronal hole that rotated into geoeffective position on July 31. The high speed stream from this CH measured at STEREO Ahead indicated that winds could reach 650-750 km/s at L1. This very strong wind will likely start impacting Earth either with or just after the CME arrives. If it “pushes” the particles in the CME, they will arrive at the leading edge of the shock. Due to the elongated shape of the CH, the period of elevated winds could be extended in duration. Here is an image of the coronal hole from SDO in AIA 211 from July 31 as it rotated toward Earth:

Coronal hole in AIA 211 from SDO on July 31
Coronal hole in AIA 211 from SDO on July 31

Together these storms have the potential to arrive with a strong shock and an extended period of high solar wind and active geomagnetic conditions. If they do, it should be a very good couple of nights for aurora hunters worldwide. As an added bonus, the Moon will be waxing just past new, so skies should be dark.

Happy Hunting!