G1 storm non-prediction

[Drax Spacex]

No one seems to have predicted this G1 storm on 25 Jan 21h-00h.  NOAA predicted the geomagnetic field to be quiet to unsettled during this time period, and they're usually conservative in their predictions.  Any guesses as to what caused this G1?  I recall seeing a CME eruption off the west (right) limb of the C3 coronagraph for January 23rd.  No one considered it to be Earth-facing, but we've recently seen that even these glancing blows can unexpectedly affect geomagnetic conditions.  Non-prediction notwithstanding, some aurora watchers out there contributed some very nice pictures to the Twitter feed.

Edited January 26, 2021 by Drax Spacex
NOAA 3-day prediction from 24-Jan

[Marcel de Bont]

You are right this was unexpected but I can see no CME that could explain these geomagnetic conditions. This looks like a coronal hole solar wind stream to me, it was just stronger than expected. Doesn't happen to often that NOAA underestimates such events but that's space weather. It can be really unpredictable!

[Christopher S.]

I was just poking around on the various online monitors and could only see a rather weak looking coronal hole stream from 22-23 now affecting us. Magnetic fields can be unpredictable when stimulated with energy, so perhaps it's just the randomness/margin of error at work. There is a bit of anomalous EQ activity going on in Europe/Eurasia(has been for a couple of weeks), so perhaps the geomagnetic field is more susceptible than usual - not to any extreme extent, and there is no confirmation of this whatsoever, but simply a thought.

[helios]

NOAA also attributed the event to an HSS.

But the wind was during the event neither particularly thin (5 to 10 p/cm³), nor fast (500 to 600 km/s), nor hot (2 to 5*10^5 K).
Certainly not typical HSS characteristics?

At speed of 550 km/s the wind would have taken around 3 days, so if it was a CME, it would have happened at around the evening of the 22nd.

In LASCO there is a bit ejecta visible over the western limb on early 23rd. I'm not sure if that could have affected earth. Here is the video from helioviewer:
https://filebin.net/a6vayw55drya1s7i/2021_01_21_20_06_08_2021_01_23_19_54_07_LASCO_C3-hq.mp4?t=j4y4cb2d (may contain a sungrazer 😉)

File expires in a week.

Edited January 26, 2021 by helios

[DarioAlbahari]

Possibly because of the Coronal Mass Ejection on Saturday Morning. 

Edited January 26, 2021 by DarioAlbahari

[Drax Spacex]

Maybe the one who 'sits above the circle of earth' doesn't always tell us ahead of time when he is going to put on a show for us 

[DarioAlbahari]

Has anyone noticed the possibility for a G1 storm on February 2nd? 

[Vancanneyt Sander]

2 uren geleden, DarioAlbahari zei:

Has anyone noticed the possibility for a G1 storm on February 2nd? 

Well there is a coronal hole currently almost center disk so we can expect a higher solar wind arrive in about 4 days. This could trigger active conditions and maybe a bit more, keep an eye on the forecasts in the next few days.

[DarioAlbahari]

yup that's what I thought

[Frank Donovan]

 

Brief minor geomagnetic storms are possible when the north-south component of the interplanetary magnetic field turns in a southward orientation (-Bz) for a few hours when combined with the effects of a coronal hole high speed stream.  Minus Bz orientation and duration is nearly impossible to predict reliably.  Thats exactly what happened.

The good news is that coronal hole high speeds are slowly becoming less frequent and less intense as we climb into solar cycle 25.  The bad news is that more frequent and more intense CMEs will cause moderate to severe geomagnetic storms starting in 2022...

[Drax Spacex]

Another apparent CME today January 29th along a similar trajectory as the one from January 23rd.  I'll go out on a limb and predict a G1 for February 1st.  If I'm wrong, I'll consider going back to my day job.

[DarioAlbahari]

16 hours ago, Drax Spacex said:

Another apparent CME today January 29th along a similar trajectory as the one from January 23rd.  I'll go out on a limb and predict a G1 for February 1st.  If I'm wrong, I'll consider going back to my day job.

Yup I predicted that same exact scenario for  February 2nd AM. 

[Jesterface23]

It looks like there are 4 CMEs now. One on the southwest backside, one near the northwest limb, a new one near the southeast limb, and another new CME somewhere on the eastern or back side. Nothing looks to be Earth directed with the latest coronagraph imagery coming in.

[Drax Spacex]

On 1/29/2021 at 4:24 PM, Drax Spacex said:

Another apparent CME today January 29th along a similar trajectory as the one from January 23rd.  I'll go out on a limb and predict a G1 for February 1st.  If I'm wrong, I'll consider going back to my day job.

Swing and a miss!  Kp2 maximum today (though popped up to Kp4 in the first 3 hours of February 2nd).  Time for me to go back to my old job, hunter-gatherer.

Edited February 2, 2021 by Drax Spacex
Active conditions 2-Feb 0h-3h