Tag Archives: geomagnetic storm watch

Space Weather to Watch October 21-27

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Northern Lights Now – After somewhat quiet space weather since the last round of aurora October 9-13, there are several features to watch again. A coronal hole is pointed towards Earth and has prompted a G1 Geomagnetic Storm watch for October 24. There is a filament to the west of the coronal hole that looks like it could lift off soon and there is an active region rotating on to the east limb that was responsible for a large backsided CME just a couple days ago. Let’s take them one by one

Annotated AIA 211 image from SDO shows coronal hole, filament and new active region.
Annotated AIA 211 image from SDO shows coronal hole, filament and new active region.

Coronal Hole

The large dark area in the center of the imange is a large coronal hole pointed towards Earth right now. It has increased in size since the last rotation and is likely to bring high speed solar wind starting in three days. When it arrives there is a good chance KP values will cross into the G1 storming range. SWPC has posted a geomagnetic storm watch for Tuesday October 24.

SWPC notifications timeline shows G1 storming expected Oct. 24
SWPC notifications timeline shows G1 storming expected Oct. 24

Filament

Just to the north and west of the coronal hole there is a filament that is looking like it may lift off soon. If it does lift off, there is a chance it could produce a CME. This is worth monitoring. It is easiest to see the filament in AIA 304 as in the animated gif here:

AnimatedGIF shows the filament to the north west of the coronal hole in AIA 304
AnimatedGIF shows the filament to the north west of the coronal hole in AIA 304

New Active Region

Potentially the most promising area of interest is the active region rotating into view on the southeast limb. This is the return of AR2674 (Aug-Sept rotation) and AR 2682 (Sept-Oct rotation) after it traversed the backside of the Sun. It should be numbered AR2684 or AR2685 later this evening.

This AR was responsible for CMEs early on Oct 18 and on October 21. The CME yesterday was from an M1.1 flare that happened just over the eastern limb. This region has shown activity over the last several days that hints that it is magnetically unstable. It seems likely that it will continue to producing flaring and possibly more CMEs.

Here is the LASCO imagery showing those two CMEs

Two CMEs appear on LASCO imagery on Oct 18 and Oct 21 as a result of activity from the active region on the eastern limb
Two CMEs appear on LASCO imagery on Oct 18 and Oct 21 as a result of activity from the active region on the eastern limb

Happy Hunting!

SWPC Issues 48 Hour G1 Aurora Storm Watch Oct 11 and 12

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Northern Lights Now – The Space Weather Prediction Center in Boulder Colorado has issued a G1 storm watch for October 11-12 indicating the potential for KP values at or above 5 and active aurora. This is due to the expected high speed solar wind coming from a large northern hemisphere coronal hole.

Northern Hemisphere coronal hole pointed towards Earth on October 7th
Northern Hemisphere coronal hole pointed towards Earth on October 7th

Models, such as the WSA-Enlil below, are predicting that the first phase of the storm should start midday on Tuesday as plasma densities rise to around 15 p/cm3. 6-12 hours later, solar wind should pick up and may reach 550 km/s. The coronal hole covers a large area longitudinally, so once the wind speed readings increase, they may remain elevated for over three days. It would not be surprising to see the G1 watch extended into a third day.

WSA-Enlil model shows density rising, then solar wind speeds increasing to around 550 km/s
WSA-Enlil model shows density rising, then solar wind speeds increasing to around 550 km/s

As of this writing, the periods of KP=5 and above are predicted to start midday on Oct 11 and continue on and off throughout Oct 12.

KP predicted to reach G1 levels on Oct 11 and Oct 12
KP predicted to reach G1 levels on Oct 11 and Oct 12

Happy Hunting

G3 Aurora Recorded Sept 27/28 – More G1 Ahead

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Northern Lights Now – The late September geomagnetic activity resulting from a large coronal hole has exceeded initial expectations reaching G3 storm levels and helping aurora hunters world-wide capture staggering views. Solar wind speeds have been between 650 and 750 km/s for just over 24 hours now. Periods of high density and negative Bz, and quickly fluctuating Bz during that time pushed KP values above 6.67 for several hours.

Recorded KP values from SWPC in Boulder indicate 7 synoptic periods for G1+, 2 with G3 stroming
Recorded KP values from SWPC in Boulder indicate 7 synoptic periods for G1+, 2 with G3 stroming

The timing worked well for aurora hunters from Northern Europe across Northern North America. Clouds disrupted viewing in the UK and New England, but many locations saw vivid displays of Green, Red and Purple overnight.

Wendy T shared this great set of 4 images

Casey Grimley captured some pinks and the coveted fishbone aurora in Ogden Valley

And Jeff Wallace shared some spectacular full sky Gree swirling aurora

Looking ahead – it seems likely that at least G1 storming will continue through at least the next 12 hours or so. SWPC has extended their G1 storm watch an additional 24 hours through Sept 29.

Looking ahead - G1 watch is extended through Sept 29
Looking ahead – G1 watch is extended through Sept 29

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