1 hour ago, Jay said:

Is the first weak CME here ?

It's hard to say, EPAM, it's still growing a little. There was no increase in density, and I think it should have increased in CME anyway. Let's wait, I think it will arrive soon.

High latitudes here seem to indicate it. Density definitely sux. Might still have a brief opening if things pick up before local sunrise in my state. ( Was directed to a cooler site less of a drive too. 😊). Tnx to member @pnw

Edited yesterday at 07:43 AM1 day by hamateur 1953

So far, it looks like a CH HSS. But it's possible that the approaching CME has affected its magnetic field.

NOAA: "Geomagnetic field activity will likely reach G1 (Minor) storm levels, with a chance for G2 (Moderate) periods, on 07 and 08 Oct due to CME effects. Primarily unsettled conditions are expected on 09 Oct as CME effects slowly wane."

My G2 prediction now includes SWPC, and I hope it comes true. However, an isolated G3 is possible where G2 is present. I would like the wind speed to drop a little more before the CME hits

I think our location might be similar to the Earth in this illustration. At the moment

I was wondering about that also ( CH) typically ragged displays and wild excursions in Bz all too typical imo. But Bz being nice to us presently at least.

1 hour ago, Samrau said:

So far, it looks like a CH HSS. But it's possible that the approaching CME has affected its magnetic field.

NOAA: "Geomagnetic field activity will likely reach G1 (Minor) storm levels, with a chance for G2 (Moderate) periods, on 07 and 08 Oct due to CME effects. Primarily unsettled conditions are expected on 09 Oct as CME effects slowly wane."

My G2 prediction now includes SWPC, and I hope it comes true. However, an isolated G3 is possible where G2 is present. I would like the wind speed to drop a little more before the CME hits

I think our location might be similar to the Earth in this illustration. At the moment

What if it is in the high G3? Things are so weird these days…

6 minutes ago, Patrick P.A. Geryl said:

What if it is in the high G3? Things are so weird these days…

The By in this graph may indicate a polarity, hinting that it may be a positive polarity CH 84 rather than a Flux Rope. In any case, By can replace Bz, but not so much. Someone already wrote that it can replace 20% of the Bz. But for G3, I think, with such a low speed of the solar wind, it still won't be enough.

Now EPAM is showing a decrease. Let's follow this up a bit more. It is possible that we are indeed already in Flux Rope. With such a weak CME and its speed similar to that of the CH HSS, this would not be surprising. But I'm still optimistic. There's still time. And for now, you can count on a substorm.

Edited yesterday at 10:21 AM1 day by Samrau

Yeah. Agreed its a weak one but the substorm probably won’t push us past G1 imho. Nice gallery btw Samrau. Haven’t even looked there in some time!! Jessica has some of her typically awesome shots too. Very nice! Maybe tomorrow night better. Nearing dawn here. 13:45 utc Tues. Nothing all night on Skunk Bay webcam and was clear. Hopefully ya do better in Europe/Asia/Australia. Maybe above 55 Degrees as a guess with these numbers.

Edited yesterday at 01:49 PM1 day by hamateur 1953
Sp? Summary

With how weak the shock was at Solar Orbiter, it seemed like L1 was going to be questionable. The IMF strength has possibly been on a gradual rise sense the 5th, so it is hard to point any arrival out.

20 hours ago, Philalethes said:

I guess this should have a separate topic of its own for discussion at this point, since we've strayed a bit from that of the current arrivals. Very interesting, though.

It would be most interesting to read a separate topic/discussion of model timing accuracy. I would certainly enjoy it. From reading posts here I believe many here including @JessicaF and @Philalethes seem to have the necessary math background to analyze this. Anyone discussing confidence intervals (CI) and curve fitting should have the basic statistical knowledge.

As interesting as It is I have to wonder how useful that analysis would be. Other than to say "the predicted arrivals were early x% of the time" or perhaps the conclusion would be "we have gotten better at predicting it over the past 10 years". There seems to be a lot of factors at work that could affect CME arrival and some may not be fully understood. For instance the interaction of a CME and any coronal holes, the state of the Sun's magnetic field at CME launch, the state of the solar magnetic field between the Sun and Earth, etc. Seems rather complicated to my simple mind.

12 minutes ago, astroHoward said:

It would be most interesting to read a separate topic/discussion of model timing accuracy. I would certainly enjoy it. From reading posts here I believe many here including @JessicaF and @Philalethes seem to have the necessary math background to analyze this. Anyone discussing confidence intervals (CI) and curve fitting should have the basic statistical knowledge.

As interesting as It is I have to wonder how useful that analysis would be. Other than to say "the predicted arrivals were early x% of the time" or perhaps the conclusion would be "we have gotten better at predicting it over the past 10 years". There seems to be a lot of factors at work that could affect CME arrival and some may not be fully understood. For instance the interaction of a CME and any coronal holes, the state of the Sun's magnetic field at CME launch, the state of the solar magnetic field between the Sun and Earth, etc. Seems rather complicated to my simple mind.

Funny, I was thinking much the same thing. It’s a very dynamic environment. During a long series of X flares that ionised the E layer I had the idea of correlating strength of them with result. My brother ( also a ham ) and a math whiz quickly discouraged me. Six variables was a bit much I guess! 😊

Something interesting started to happen, the density increased a little, but the temperature dropped and remained at low values, 10,000K.

👀

It looks like we're in Flux Rope. That's all we can expect from this event. We might reach G1, but with these parameters, we won't achieve anything more.

Well, okay, we have Coronal Hole 85 next! They are very geoeffective these days, I hope we will be pleased with it this time too

Amen to that. What we all need are CH that are coincident with New Moon. Asking too much? We hope not…. 😊

It looks like we entered Flux Rope at ~16:16UTC.

The solar wind velocities and temperatures have been low for over the past 24 hours. The solar wind density is near constant or has been going up by a very small amount. So, we're pretty much back to one of those 50/50 guesses.

Looking at most of the terrestrial Magnetometers, it seems to have settled into background again. Although hemispheric power remains elevated a bit still. We might still have another minor storm. But wind speed at 400. Doesn’t seem too likely.

Edited 14 hours ago14 hr by hamateur 1953

It seems that Solar Orbiter yesterday at 11 or 10 UTC had a corona hole impact or other CME that caused almost 50 bt and dropped to almost 0 bt, I don't know how real that is and if it can get here but

October 7

Edited 13 hours ago13 hr by Isatsuki San

55 minutes ago, Isatsuki San said:

It seems that Solar Orbiter yesterday at 11 or 10 UTC had a corona hole impact or other CME that caused almost 50 bt and dropped to almost 0 bt, I don't know how real that is and if it can get here but

October 7

Must always be remembered that the field strength drops off with distance according to roughly an inverse square law, or a similar power law using some other exponent; I know 1.6 has been found as a best fit in one paper, so I use that as the higher bound myself when doing a rough estimate.

The peak of nearly 50 nT was also extremely transient, but if use that for the estimate, and having SolO at ~0.5 au, we get a lower bound of 50 * 0.5^2 = 12.5 and a higher bound of 50 * 0.5^1.6 = ~16.5; so it would correspond to something like 12.5-16.5 nT at 1 au (where Earth and more or less where L1 is, the latter technically at 0.99 au). That's how I do a rough estimate of the field strength values measured by SolO personally at least.

3 minutes ago, Philalethes said:

Siempre hay que recordar que la intensidad del campo disminuye con la distancia según aproximadamente una ley del cuadrado inverso, o una ley de potencia similar que utiliza algún otro exponente; sé que 1,6 se ha encontrado como el mejor ajuste en un artículo, por lo que lo uso como el límite superior cuando hago una estimación aproximada.

El pico de casi 50 nT también fue extremadamente transitorio, pero si lo usamos para la estimación, y con SolO a ~0,5 ua, obtenemos un límite inferior de 50 * 0,5^2 = 12,5 y un límite superior de 50 * 0,5^1,6 = ~16,5; por lo tanto, correspondería a algo así como 12,5-16,5 nT a 1 ua (donde se encuentra la Tierra y aproximadamente donde se encuentra L1 , este último técnicamente a 0,99 ua). Así es como hago una estimación aproximada de los valores de intensidad de campo medidos por SolO, al menos personalmente.

Hey Phi, can I ask you why Solar Orbiter's BT sometimes reaches almost 0?

And another Type II. 20:00. UTC. Haven’t heard anything interesting about this yet.

46 minutes ago, Isatsuki San said:

Hey Phi, can I ask you why Solar Orbiter's BT sometimes reaches almost 0?

Not 100% sure, but there are various magnetic null points around where fields of opposite polarity reconnect, which prominently happens between the sectors of the Sun of different polarity, forming the heliospheric current sheet. Typically there is turbulence around the sheet that we register as enhancements in the wind, but right at the transition you'd essentially measure a field strength of nearly zero as the field reverses, so it could be that SolO is showing that more clearly for some reason. As you can see in this case that dip does coincide with the transition from positive polarity (B_R > 0) to negative polarity (B_R < 0, which is the polarity the CH whose CIR/HSS it's passing through has), also known as the sector boundary crossing (SBC), so my best guess is that it would be related to that somehow.

1 hour ago, hamateur 1953 said:

And another Type II. 20:00. UTC. Haven’t heard anything interesting about this yet.

Guessing it's related to this at roughly that time, which certainly looks impressive, but which doesn't seem to show any signature at all in the coronagrams so far:

Here it is, a weak and questionable CME. I expected the solar wind to drop to 300-350, but it didn't. Then I expected the Earth's angle relative to SolO to be more favorable, but it wasn't. Apparently, the densest region of the CME passed below the Earth. Although we didn't get an auror, it was interesting to watch.

Did this CME actually arrive then? I see a lot of back and forth about the metrics but no one seems a certain if there was an impact...?

39 minutes ago, Stella said:

Did this CME actually arrive then? I see a lot of back and forth about the metrics but no one seems a certain if there was an impact...?

Unless a miracle happens tonight, our best bet is the next CIR. The previous rotation, it was excellent despite being powered by a negative polarity CH. Fingers crossed!