X1.4 Flare and CME (‘solar storm’) with earth-directed components

Update 2026-03-31, 2200z

X1.4 flare from region 4405, creating a large and fast coronal mass ejection (CME) (≈ 1800 km/s) towards the south-east. The coronal hole to the north-west is located between the CME and the Earth and will slow down the CME. If the CME is able to cross the high-speed stream, it could arrive together with the stream interaction region. This constellation leads to high uncertainty.

Arrival is expected between the morning of 31 March and the morning of 1 April (glancing blow to flank hit). A geomagnetic storm of strength G1 (MINOR) to G4 (SEVERE) is possible, G2-G3 likely. Depending on how strong the impact will be, there is a good chance of mid-latitude aurora.

The eruption

2026-03-30, 1200z – The flare is localised in S27 E42, the strength was X1.4 (SWPC) or X1.5 S25 E45 (SolarSoft)

Start time 0247 UTC (2026-03-30), peak 0319 UTC – flare still ongoing (= X-ray flux is still elevated; 1218 UTC)

You can see the flare and a coronal wave spreading in all directions. Dimming south, west, north and especially east. Field lines open to the south-east on a large scale. This is the main direction of the CME. The coronal hole in the north-west is a barrier – but this time it does not seem to have deflected the CME too much to the south-east. Presumably the CME can pass the high-speed stream without any problems (but this is not certain!)

The flare created an R3 radio blackout (shortwave interference) – SEPs (Solar Energetic Particles) have not been measured so far – maybe none were released, maybe the coronal hole is still shielding them and we will see an increase later.

Radio emissions

2026-03-30, 1200z

• Strong “tenflare” (2.6 GHz microwave radio burst): 1800 sfu (background 158 sfu) – interference with radar, GPS and satellite communication
• Type II radio sweep at 1872 km/s (CME with shock at this speed – estimated)
• no Type IV burst – so probably no energetic particles

The coronal mass ejection (CME, solar storm)

2026-03-30, 1200z

The shock/full halo in SOHO LASCO C2 is clearly visible.

SOHO LASCO C3 shows the propagation of the CME. There appear to be earth-directed components.

CCOR-1 Running Difference also shows earth-directed components (in the west, i.e. on the right)

Update 2026-03-30, 1900z – Change Log

• Added STEREO A COR2 images
• Added latest model run results
• Added radio spectrograms

CME analyses and forecasts

Status 2026-03-30, 1900z

The predictions are very inconsistent, from glancing blow to hit, with stream interaction region arrival (and thus compression/amplification of the CME) – the arrival times are also calculated very differently.

Further model results will be published here when available

I estimate arrival late on 31 March and G3 STRONG STORM is a realistic scenario – but it cannot be ruled out that the CME might miss the Earth entirely.

Radio Spectrograms

2026-03-30, 1900z

The Siberian Radioheliograph (SRH), based at the Institute of Solar-Terrestrial Physics (ISTP) of the Siberian Branch of the Russian Academy of Sciences (SB RAS) near Irkutsk, Russia, has detected the microwave burst and Type II/Type III bursts. The emissions in the GHz range originate mainly directly from the flare in the lower corona and the chromosphere. ☞ https://badary.iszf.irk.ru/SP_3_24.php

The e-Callisto network also provides data on radio emissions – in this case from ASSA Australia. With the right expertise, Type II bursts can be identified from this data and their speeds measured. The emissions after 0315z originate mainly from the CME in interplanetary space. ☞ https://www.e-callisto.org/Data/data.html

Updates

2026-03-31, 0200z – Dr Tamitha Skov visualises the tilt

The CME is tilted in such a way that we will likely not be hit by its core and will only pass through its outer edge (the ‘envelope’). Nevertheless, the shock wave and the approaching stream interaction region could provide enough magnetic energy to trigger aurora at mid-latitudes.

2026-03-31, 0200z – What happened before the X1.4 flare?

A minor filament disruption followed by a cascade of reconnecting loops in the north destabilised the whole complicated magnetic system between region 4405 and a small active region north of it. Finally, the stress was released by the eruption of a core filament from 4405, accompanied by a large area of coronal magnetic field that was evacuated into interplanetary space.

2026-03-31, 1900z – CME is approaching

The sharp rise in proton levels detected by the ACE-EPAM instrument, accelerated by the CME, indicates an approaching interplanetary shock. If this rise continues at this rate, the impact is imminent.

2026-03-31, 2200z – CME Still Not Here

The alert was apparently a bit premature. Now the signs of an imminent impact have faded again, and the chances of a stronger impact are dwindling.

2026-03-31, 2200z – Synoptic Map

Active regions

• 4401, 4402, and 4399 in the west are quiet and tending toward decay
• 4403 is continuously ejecting filament material northward near the surface
• 4407, 4404, 4406 are showing no clear development trend but have accumulated many filaments – with a slight increase in activity or changes of the magnetic surface field, one of them could erupt
• 4408 and 4409 are growing and are trans-equatorially connected to 4405, giving them increased flare and CME potential
• 4405 is now in the earth-strike zone. It has a sigmoid structure at its center and could erupt again soon despite its relatively simple magnetic structure, likely with another strong flare + CME

Coronal Holes

• CH34+ in the west is receding and slowly decoupling from Earth
• CH36– in the center has increased in size and will soon determine space weather near Earth. The arrival of the stream interaction region is expected April 1 or April 2. With support, i.e., amplification from the shock and the nearby passage of the CME from March 30, G1–G2 geomagnetic storm intensity could then be reached (MINOR – MODERATE)

2026-04-01, 1430z – Shock wave arrived

Around 1130 UTC, the interplanetary magnetic field (IMF) jumped from about 6 nT to about 15 nT, making it more than twice as strong as before. The speed briefly jumped from 400 to 500 km/s and is now at a slightly above-average 450 km/s. Density and temperature have also risen.

We are still in the positive magnetic sector, i.e. the influence of coronal hole CH34+ persists—we have not yet crossed the Heliospheric Current Sheet (HCS)/ the streamer belt/ the Solar Sector Boundary (SSBC), and the Stream Interaction Region (SIR) of the High-Speed Stream (HSS) from coronal hole CH36+ has not yet reached us. The shock has likely fought its way through this barrier and was weakened in the process.

Whether we are already seeing the Stream Interaction Region or not cannot be determined with certainty, but I expect a further increase in IMF strength, velocity, and density. However, we will likely not see a beautiful, well-structured magnetic field from the Interplanetary Coronal Mass Ejection (ICME).

The SIR will likely reach us together with the HCS and the edge of the ICME in the course of April 1, causing increased geomagnetic activity that will then last until at least April 2. A G3 STRONG STORM (Kp7) is off the table for now, I’d guess. A G2 MODERATE STORM (Kp6), however, could easily be reached with the passage of the SIR.

Whether it will be enough for mid-latitude aurora remains to be seen. We have a full moon, and any potential aurora will be bleached out by the bright background. It might still be worth keeping an eye on the activity, though. The coronal hole with its fast solar wind has the “right” polarity for this time of year (negative); we are near the equinox, and the Russell-McPherron effect and the equinoctial effect are conducive to geomagnetic storms.

The probability that Region 4405 will fire off another CME is high, especially in conjunction with the connected northern regions 4408 and 4409. An exciting situation, also for the Artemis II mission with its planned flight to the Moon (another launch attempt today, April 1, at 22:24 UTC at sunset in Florida). Space weather is the last thing the mission needs right now.

Analysis of this event and what happens next:
Circus tent and toilet lid – filament eruptions, fast solar wind and a new complex region

More updates always on X or bluesky

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