Tag Archives: coronal hole

Late October 2017 Aurora Strom Live Blog

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Northern Lights Now – Space weather forecasters are predicting 3 days of active aurora conditions. NLN is activating the live blog. We’ll aim to update a couple times a day, or as warranted, so check back often

NLN Live Blog Update – Fri, Sept 27, 02:15 UTC (23:15 EST 10/26)
Live blog time: 74h 15m

We’re calling it. This storm is over. Solar wind speeds have dropped back below 500 km/s. This storm netted two periods of G1 storming. Thank you for tacking it with NLN!

NLN Live Blog Update – Thurs, Sept 26, 13:30 UTC (10:30 EST 10/26)
Live blog time: 61h 30m

The Magnetosphere is now starting to rattle a bit. Bz has sustatined a negative orientation for over 6 hours. This is conducive to aurora and geomagnetic activity. KP has been between 4 and 5 for several hours now. If this continues, G1 is almost certain and G2 is possible.

In the DSCOVR wind chart below, the red bar shows that Bz has been negative for over 6 hours, the two blue bars show that wind speeds have been > 500 km/s for over 48 hours.

Solar wind now conducive to G1 storming
Solar wind now conducive to G1 storming

NLN Live Blog Update – Thurs, Sept 26, 03:15 UTC (23:15 EST 10/25)
Live blog time: 51h 15m

It has been quiet today on the aurora front. Total magnetic fields (Bt) have stayed relatively weak for ranging between 4 and 6 nT, and Bz has been variable. With no prolonged periods of strong Bz south, there has been very little aurora activity. There was one period of G1 storming today and no periods of G2.

Solar wind speeds are still elevated at around 600 km/s and there could be a prolonged period of Bz south at any point, but with each passing hour it is less likely. Today’s busted storm watch goes to show that we need more data from additional satellites to do a really good job of forecasting geomagnetic activity.

Despite the low activity, some aurora reports for the higher latitudes are coming in:

NLN Live Blog Update – Tue, Sept 25, 03:15 UTC (23:15 EST 10/24)
Live blog time: 27h 15m

Solar winds have continued to increase over the last 6 hours and are now in the 600 km/s range with a brief peak above 625 km/s. There was a period of about an hour where Bz was predominantly negative and it produced a period of G1 storming. So far this nearly exactly confirms the posted watch for 10/24. Wing KP models also registered a short term prediction of KP=5.67 for around 02:00 UTC, but this was not measured on the ground. Here is the chart of the measured KPs so far for this storm:

Recorded KP values from boulder confirm the 10/24 G1 storm watch
Recorded KP values from boulder confirm the 10/24 G1 storm watch

NLN Live Blog Update – Tue, Sept 24, 16:15 UTC (12:15 EST 10/24)
Live blog time: 16h 15m

Earth has now entered the high speed wind stream. Solar wind speeds are now registering around 525 km/s after being around 350 km/s just 6 hours ago. Those should increase to over 600 km/s in the next 12 hours. Geomag activity is already responding, KP values have increased to just above 4. There are still several hours before it will reach G1 storming levels.

KPSlowlyClimbing_20171024

Solar wind speeds have increased from around 350 km/s to over 525 km/s
Solar wind speeds have increased from around 350 km/s to over 525 km/s
KP values climbing over 4
KP values climbing over 4

NLN Live Blog Update – Tue, Sept 24, 11:15 UTC (07:15 EST 10/24)
Live blog time: 11h 15m

Have you been watching the density after the last update? It has increase to around 40 p/cm3. It’s very likely solar wind speeds will increase in the near future.

NLN Live Blog Update – Tue, Sept 24, 04:00 UTC (00:00 EST 10/24)
Live blog time: 04h 00m

No sign of the expected solar wind yet. The first signs it is on it’s way will be that the proton density rises as earth enters the co-rotating interaction region (CIR). That sounds uber-technical, but all it means is that there are two streams of solar wind moving towards earth at different speeds. At the place they meet, there is a region where they interact. It means we know there is a period of fast solar wind coming when the proton density measured at DSCOVR increases. For now, Density is at nearly background levels around 5 p/cm3

Proton density is still at nearly background levels.
Proton density is still at nearly background levels.

NLN Live Blog Update – Tue, Sept 24, 00:00 UTC (20:00 EST 10/23)
Live blog time: 00h 00m

The NLN live blog is activated. We’ll bring news and updates about the predicted solar storm over the next 3-4 days. Here is the current three day auroraCast clock showing G1 predictions on Oct 24 and 26 sandwiching G2 forecasts for OCt 25.

NLN AuroraCast shows three days of G1 and G2 activity from October 24-26
NLN AuroraCast shows three days of G1 and G2 activity from October 24-26

G1-G2-G1 Storm Watch for Oct 24 through October 26

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Northern Lights Now – High speed wind from the coronal hole mentioned in the previous NLN post is expected to arrive sometime on October 24 and should induce G1 and G2 storm conditions through the 26th. SWPC has issued storm watches for all three days with G1 watches on the 24th and 26th and a G2 storm watch on October 25. This means KP levels could reach 5.67 or more.

SWPC notifications timeline shows three days of storm watches posted
SWPC notifications timeline shows three days of storm watches posted

Models are predicting an extended period of elevated solar winds reaching as high as 650km/s for all three days. The initial winds will arrive with a CIR (co-rotating interaction Region) where densities are higher and the magnetic fields are more complex. This means you can monitor the progress of the arriving wind stream – it will show up as proton densities as measured at L1 by DSCOVR will rise. Once Earth is in the body of the high speed solar wind stream, density decreases and winds increase.

Current forecasts show geomagnetic activity reaching G1 levels (KP=4.67 and above) the second half of Oct 24, then reaching G2 (KP=5.67 and above) on the first part of Oct 25. Activity should slowly decline over the following 36 hours, but there may be spike of activity if the magnetic fields line up just right.

NLN AuroraCast shows three days of G1 and G2 activity from October 24-26
NLN AuroraCast shows three days of G1 and G2 activity from October 24-26

As an update to the features in that previous post, the filament did lift off, but was subsequently reabsorbed, so it did not generate a CME. The active regions rotating into view on the East limb seem to have lost their magnetic complexity. Space Weather forecasters are not expecting they will be active flare producers in the next several days.

Happy Hunting!

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!