The sun is seething – strong flares and a train of earth-directed CMEs (solar storms) on the way

Update 2026-06-07, 0600 UTC

Active region in the centre of the visible solar disc is growing and producing solar flares and coronal mass ejections. Several of them earth-directed so far, possible hits from late 4 June, up to G3 STRONG possible (uncertain) – thus also mid-latitude aurora. However, bright nights in the northern hemisphere and the proximity to the solstice will make aurora hunting more difficult.

CME = Coronal Mass Ejection = Solar eruption = Solar storm

Overview (synoptics)

2026-06-03, 1800 UTC – 10 active regions were on the visible solar disc on 2 June. Most simple and small. Region 4455 shows rapid growth and increasing complexity – producing eruptions that are partially directed towards Earth.

The coronal hole CH62+ is located at the solar equator – its stream interaction region and subsequent fast solar wind is expected today on 3 June (increased speed up to 500/600 km/s and increased geomagnetic activity possible).

Solar flares

We are seeing a significant increase in the number and strength of solar flares. They all originate from region 4455, the last large one an X-flare (X1.0) – if the development continues, we can expect further X-flares.

Region 4455

Region 4455 has existed for a while (emergence at the eastern limb), its trailing part no longer contains any sunspots – a plage region, but the leading section shows the emergence of new sunspots of opposite polarity around the main spot. As they appear on the wrong side, so to speak, we call the configuration “Anti-Hale”, it should actually look like this in the southern hemisphere – this is not untypical for the declining phase of the sunspot cycle.

Far side of the sun (Solar Orbiter)

For a few weeks now, we have been seeing increased activity on the back side of the sun with stronger flares and larger CMEs – on the side facing the Earth, it has remained quiet until recently. This is different now.

Region 4436 was responsible for several major CMEs and probably also for a radiation storm (S1 MINOR) that recently reached us. The probability that the region is still active is relatively high.

Events

2026-06-03, 0122 UTC – M9.3 flare and halo CME

A rather inconspicuous eruption at first glance, but with a rapid CME

Radio emissions

A type IV radio storm and a microwave radio burst (“tenflare”) were detected in connection with the event – both indications of an eruptive event with CME.

☞ https://ovsa.njit.edu/eovsadata/?date=2026-06-03

STEREO A COR2

GOES CCOR-1

A full halo can be seen in the GOES CCOR coronagraph and a poorly visible front to the north-west.

Heliospheric Imager

The side view from the STEREO A satellite does not provide a particularly helpful view of the situation. We see an existing structure, presumably older ejecta, possibly with earth-directed components, which is caught up by a structure to the north – presumably our CME.

☞ https://stereo-ssc.nascom.nasa.gov/browse/2026/06/03/index.shtml

NASA M2M Run

CME analysis (corrected)

Longitude: 19°, Latitude: 14°; Speed: 1220 km/s, Width: 64°; Time at 0.1 AU: 2026-06-03T04:15Z

CME with 1220 km/s, relatively earth-directed could flank us early on 5 June . Calculated possible maximum Kp values between 5 and 7, i.e. G1 MINOR to G3 STRONG geomagnetic storm possible.

☞ https://kauai.ccmc.gsfc.nasa.gov/DONKI/view/CME/46585/1
☞ https://kauai.ccmc.gsfc.nasa.gov/DONKI/view/WSA-ENLIL/46610/1

2026-06-03, 0649 UTC – M7.7 flare and partial halo CME

Massive ejection to the north/north-west with partial halo and shock wave

STEREO A COR2

GOES CCOR-1

NASA M2M Run

CME analysis (Leading Edge)

Longitude: 19°; Latitude: 52° (!); Speed: 1470 km/s; Time at 0.1 AU: 2026-06-03T09:27Z

CME analysis (Shock)

Longitude: 9°; Latitude: 20°; Speed: 1130 km/s; Time at 0.1 AU: 2026-06-03T10:05

We probably won’t see much of the CME itself, but its shock front could reach us on 5 June and strengthen an existing storm.

☞ https://kauai.ccmc.gsfc.nasa.gov/DONKI/view/CME/46596/1

2026-06-03, 1119 UTC – X1.0 flare and partial halo CME

CME to the north with earth-facing parts

STEREO A COR2

Two-lobed CME

GOES CCOR-1

The Shock spreads mainly to the north-west, but there is also a front to the east – this is the part that could flank us.

NASA M2M Run

CME analysis (Leading Edge)

Longitude: 19°, Latitude: 32°; Speed 1430 km/s; Width: 77°; Time 0.1 AU: 2026-06-03T13:49Z

CME analysis (Shock)

Longitude: 20°; Latitude: 30°; Speed 1400 km/s; Width: 86°; Time 0.1 AU: 2026-06-03T13:57Z

NASA calculates an impact early on 5 June (around 0800 UTC) with maximum possible Kp values of 4-6 (ACTIVE – G2 MODERATE) geomagnetic activity.

Multi-CME runs

SWPC/NOAA

G3 STRONG STORM Watch is issued by SWPC/NOAA for 4 June and 5 June 2026

At the US space weather service SWPC, the CMEs will arrive in a cluster late on 4 June (UTC) and a fairly strong impact is expected.

☞ https://www.swpc.noaa.gov/products/wsa-enlil-solar-wind-prediction/

MOSWOC (Met Office)

G3 STRONG STORM Watch is issued by Met Office UK for 2026-06-04, 13:00 UTC – 2026-06-06, 09:00 UTC

The latest Enlil run of Met Office does not yet contain all CMEs. It will be published here when an update is released.

☞ https://swe.ssa.esa.int/metoffice-enlil-e-federated

NASA

NASA ‘s multi-CME run calculates a combined arrival around 2026-06-05, 0000 UTC; Kp 6-8 (G2 MODERATE to G4 SEVERE); plasma velocity close to Earth up to 700 km/s

☞ https://kauai.ccmc.gsfc.nasa.gov/DONKI/view/WSA-ENLIL/46624/1

HUXt

The HUXt model based on NASA M2M analyses calculates a combined impact at midnight 4.6./ 5.6. with solar wind speeds close to the Earth of over 1000 km/s. Three CMEs with an increased probability of a hit (45%, 80%, 47%).

☞ https://swxforecastlab.org/forecasts.html

ELEVo

A good impression of the overall situation with NASA M2M CME analyses is provided by ELEVo from the Austrian Space Weather Office ASWO in Graz.

☞ https://helioforecast.space/cme

Updates

Current updates on the previous and possibly newer CMEs can be found here.

2026-06-04, 2000 UTC – No clear signs of an imminent impact

☞ https://www.swpc.noaa.gov/products/solar-wind?layout=ions# start=2026-06-02T12:21:56&end=2026-06-05T20:06:54

The new solar wind module from the US Space Weather Prediction Centre (SWPC) shows the rise in suprathermal protons typical of CMEs with shock fronts, which are accelerated by the shock front itself. A sudden steep rise indicates an imminent impact, but there is no sign of this yet. The arrival may therefore still be some time away.

HI2 shows blurred CME structures approaching Earth. It is difficult to determine an exact arrival time from the few images and the poor image quality.

On 3 June, HI1 shows the front of the CME associated with the X1.0 flare. It looks impressive and suggests that the third CME may produce the strongest impact.

2026-06-05, 1800 UTC – A bumpy CME ride with an uncertain outcome

At around 0430 UTC (06:30 CEST), an interplanetary shock arrived at the L1 point; a CME signature had already been detected in the solar wind beforehand, albeit with a weak magnetic field and moving slowly. The interplanetary magnetic field began with a strong northern orientation and thus low geoeffectivity, temporarily reaching significantly southern values (Bz–), which led to a few red Aurora Australis rays, visible in New Zealand and Tasmania. Afterwards, the magnetic field became turbulent – presumably in connection with the arrival of the solar wind from the coronal hole CH62+.

Since around 1500 UTC (17:00 CEST), it has been looking more like a CME again. It could be that this is now the third and therefore the last one – but that is by no means certain. Should Bz remain in negative territory, the probability of auroras would increase significantly. However, the window of opportunity for possible sightings in Central Europe is short. Astronomical twilight begins at 23:29 CEST in Berlin; there is no night. The 78% bright moon rises at 01:03 CEST on 6 June in Berlin.

2026-06-07, 0600 UTC – Little aurora, but noctilucent clouds

Around 2026-06-05, 2250 UTC (6 June 2026, 0050 CEST), a faint, diffuse violet glow was visible on the northern horizon on some Alpine webcams. However, that was all there was to it, as the expected third CME (associated with an X1.0 flare) was exceptionally weak – analyses showed that it did not cross the ecliptic plane and thus passed us by, mainly to the north.

Post on the AKM forum:
Polarlicht 2026-06-05/06(?)

From around 02:00 CEST (00:00 UTC), noctilucent clouds appeared on the northern horizon – moving from north-east to south-west. The display was exceptionally bright.

Post on the AKM forum:
NLC 2026-06-05/06

2026-06-07, 0600 UTC – Analysis

HaloCME (Nariaki Nitta) has created AIA Running Ratio videos of the three eruptions mentioned above, as well as another one on 2 June 2026. He believes that the first one in particular, which is not listed here, contributed to the G2 geomagnetic storm, whilst the others contributed only marginally or not at all.

• “I use AIA running ratio movies in color to find the extension of solar eruptions. This captures the M3.3 flare in AR 14455 (2026-06-02 16:31). An unrelated eruption on the east limb was impressive, but the M3.3 eruption may have been the central ingredient of the latest G2 storm.”
  https://x.com/halocme/status/2063348382702182833
• “For completeness, I am posting AIA running ratio movies for the other three major flares that occurred on 2026-06-03 in AR 14455. This is for the M9.3 flare at 01:22 UT. Quite benign as far as the low corona was concerned.”
  https://x.com/halocme/status/2063349820505432407
• “This is for the M7.7 flare starting 2026-06-03 06:49. The filament eruption was quite gorgeous, although coronal waves were suppressed. The associated CME was heading mostly to northwest. I doubt this contributed to the geomagnetic storm.”
  https://x.com/halocme/status/2063352165926609029
• “Finally, the X1.0 flare (2026-06-03 11:19). Again, I thought the eruption was not too disruptive, and the CME did not go beyond the ecliptic (based on STEREO COR2 science data).”
  https://x.com/halocme/status/2063353699863302546

He may be right.