CME parade underway; midlats aurora not ruled out

Update 2026-10-09; 1800 UTC

Several CMEs are on their way, roughly heading towards Earth, but they have all been deflected northwards and are likely only to graze the Earth. Aurora may be visible from 10 October, particularly in the higher mid-latitudes. From around 11 October, a large trans-equatorial hole extending far southwards will begin to affect the Earth. Synergistic effects with the CMEs are possible.

CME = coronal mass ejection = solar storm

Synoptic

Sunspot Group 4549

It is complex; it is still evolving and, from time to time, emits flares and releases CMEs. It will likely continue to do so, but as it moves away from the Earth-strike zone, Earth-directed CMEs from it are becoming less likely.

High-speed stream

The coronal hole in the south and east is causing the CMEs to be strongly deflected towards the north-west; the high-speed streams can even be spotted in the coronagraphs.

Solar wind speeds of over 700 km/s are possible from 12 October onwards; however, the stream is negatively polarised, which is unfavourable for Aurora at this time of year.

CME 1 – 2026-10-06 (M1.4 flare, M1.8 flare)

As discussed in the previous article:

☞ M-class flare and a CME heading almost directly towards Earth spacewx.org/m-class-flare-and-a-solar-storm-towards-earth

☞ www.youtube.com/watch?v=PDhIs2WfZKc&t=799s

CME 2 – 2026-10-07 (C6.7 flare)

On 7 October, there was another eruption, accompanied by a rather unremarkable CME heading north-west.

It will probably be overtaken by the next CME.

CME 3 – 2026-10-08 (M6.8 flare, filament eruption)

A moderate M6.8 flare with Type II and Type IV radio bursts. A small, very dense core filament is initially catapulted towards the north-east, followed by another towards the north/north-west. Later, a large filament erupts in the south-east, appearing in the coronagraph as a CME heading north. The coronal hole blows them all away from Earth.

Corona

Radio emissions

There’s a lot going on across the entire radio spectrum – a great deal of energy is being released here

All data from the Owens Valley Solar Array https://ovsa.njit.edu/

Predictions

SWPC

The Space Weather Prediction Centre in Boulder, Colorado, has simulated three CMEs from 6 October, 7 October and 8 October, travelling at 571 km/s, 499 km/s and 912 km/s respectively. The last CME will catch up with the one in the middle. A first wave will reach us on 9 October, and a second on 11 October. The high-speed stream is still relatively far away at that point in SWPC’s Enlil model. That probably isn’t the case. I reckon its stream interaction region will also be affecting us from 11 October onwards.

SWPC has issued a G2 (MODERATE STORM) watch for 9 October and a G1 (MINOR STORM) watch for 11 October.

HUXt

HUXt, using NASA analyses and BRAVDA background solar wind data, also shows two peaks in solar wind speed; here, the transition into the high-speed stream is simulated more accurately, albeit significantly later, which probably means it is not entirely accurate either. It is interesting to note that NASA estimates the CME of 8 October to be significantly slower than SWPC (500 km/s vs. 900 km/s).

Conclusion

As always, anything is possible: from almost nothing to a surprisingly strong, prolonged impact. The arrival of the stream interaction region is relatively certain, but the exact time of its arrival is uncertain.

Updates

2026-10-10, 1700z – Strong Impact 2026-10-10; 14:30 UTC

2026-10-10; 17:00 UTC – Magnetic field partly above 40 nT; Bz initially mainly to the north, recently turned negative (south) at around -20 nT, high velocity now at 700 km/s, density initially above 100 particles/ccm; if Bz remains negative, there is a good chance of widespread aurora in Central Europe, perhaps even visible to the naked eye – this mainly affects the northern (poleward) horizon, but if the situation persists, the auroral oval could also drift very far towards the equator.

Disruptions to GPS and radio communications, particularly at lower frequencies, are to be expected.

2026-10-10, 1800z – Aurora in Central Europe

Green proton arc and red rays, with a green aurora oval arc behind; 1750 UTC

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