2025-03-02 - Solar activity + forecast

👉 Update 2025-03-08 2200 UTC

The high-speed stream of a coronal hole has reached us and could cause some episodes with aurora on the northern horizon. The CME after an M1.6 flare on 7 March around 2100 UTC will probably miss us to the south on 10 March.

Content

Summary (2.3.)
The current space weather (2.3.)
2025-03-01 1800z – Large filament eruption & CME towards Earth – chance of G2 MODERATE STORM from 4 March.
2025-03-03 – The CME has reached Solar Orbiter
2025-03-04 – The CME has reached L1 (the Earth)
2025-03-05 – 00:10 – Aurora in Central Europe
2025-03-05 – Current space weather & outlook
2025-03-07 2200 UTC – M1.6 Flare produced a strongly southward deflected CME
2025-03-08 – Connection with High Speed Stream begins
2025-03-08 18:30 UTC – Strong magnetic convection – aurora likely
2025-03-08 22:40 CET – Aurora in the north

Summary (2.3.)

After a somewhat more active phase of the sun with M- and X-class flares, radio blackouts, CMEs and even a small radiation storm, calm has returned. The influence of the fast solar wind is decreasing and the Earth’s magnetic field is quiet again.

From Tuesday (4.3.) there is a chance of a glancing blow of a coronal mass ejection (CME) directed more to the south/southeast after a filament eruption. The effects on Earth will probably be moderate (G1 MINOR STORM) if we get anything. The chances of auroras in Central Europe (northern horizon) are quite good.

The current space weather (2.3.)

The coupling with the coronal hole CH19 decreases and with it the solar wind speed.
The strength of the interplanetary magnetic field is currently below average at just 3 nT.
The Earth-directed active regions on the visible solar disc are not very large and show hardly any dynamics.

Composite of SDO HMI magnetogram (blue and red) and SDO AIA 193, 211 and 171 Å shows some active regions without much dynamics in the centre of the solar disk (i.e. Earth-directed), the departing large coronal holes at the western limb, a new large coronal hole at the eastern limb (negatively polarised), new active regions near the south-eastern edge and the southern half with large filament structures. In the course of the video, a filament eruption can be seen that has produced a CME and subsequently an eruption behind the eastern rim on the far side.

The next large coronal hole with a strong north-south extension can already be seen on the eastern limb (CH21/- negatively polarised – favourable in spring for geo-effectiveness), which could become weather-determining in about a week, again with speeds of over 600 km/s.
For the next few days, there is not much chance of stronger flares and associated eruptions.
At the eastern limb, several smaller active sunspot regions are currently rotating into view, certainly with dynamics and growth, partly with development in the coronal hole (anemone active region).

2025-03-01 1800z – Large filament eruption & CME towards Earth – chance of G2 MODERATE STORM from 4 March.

SDO composite image of 193, 211 and 171 Å and 211 Å runtime difference shows a large filament eruption in the southeast around 1800 UTC on 1 March with a large dimming region and subsequent brightening and posteruptive arcades and loops

The CME is pointing quite clearly to the south and is expected to reach Solar Orbiter on 3 March; it could glance the Earth late on 4 March (24 hours later). The launch speed is estimated by Met Office at 550 km/s, NASA M2M comes to 566 km/s.

Automated CME analysis with SOHO/LASCO C2 runtime difference image of SEEDS

NOAA/SWPC’s new CCOR-1 coronagraph in geosynchronous orbit shows a CME to the southeast (bottom left)

Enlil-Lauf von Met Office. Oben die Dichte, im rechten AusschnittEnlil run from Met Office. Above the density, in the right section the lateral cross-section shows a CME pointing mainly southwards, at speed (below) it barely stands out from the background.

NOAA/SWPC has issued a G1 Watch for 4 March and 5 March, Met Office also sees chances of G1/G2 from 4 March and NASA M2M calculates chances of G1 MINOR / G2 MODERATE STORM from 4 March, too. HUXt Ensemble with 500 members sees a 50% chance of a hit.

2025-03-03 – The CME has reached Solar Orbiter

As predicted, the CME (now as ICME) has reached the Solar Orbiter spacecraft near Venus around 2025-03-03 1400 UTC. The interplanetary magnetic field there reached a maximum strength of 35 nT, which is 7 nT more than NASA M2M calculated. For the Earth, 12 nT was estimated with arrival in the late afternoon/early evening on 4 March – perhaps it will be a little more. But we can hardly expect more than 20 nT.

The Bz component at the Sol.O. (there as B_N) fluctuates quite strongly between +30 and -30 nT, presumably the entire CME rotates – not unusual for such elongated filament eruptions. At least it feeds the hope for some sufficiently southerly Bz component tomorrow evening and a bit of aurora in Central Europe.

2025-03-04 – The CME has reached L1 (the Earth)

… or rather the proximity of the Earth, because the effects are not very strong (so far). Around 1900 UTC (20:00 CET) there was a small jump in the interplanetary magnetic field from 5 nT to 8 nT, the density rose briefly from 1 to over 10 p/cm3 and then fell to very low values, the speed jumped from 430 to 530 km/s. Since then Bz has been negative (-7.7 nT). It remains to be seen how the values will develop. A further increase is conceivable, but perhaps that was already the maximum.

☞ Aktueller Sonnenwind

IPS tomography shows the plasma density in interplanetary space – the CME has probably hit Solar Orbiter well, the Earth is only glaanced at best. Top left is a cross-section through the ecliptic, with the Sun in the centre and the Earth on the right; we are looking at the Sun’s north pole. Below, a cross-section, north at the top, south at the bottom, Earth on the right.
Source: UCSD, provided by NASA/ISWA

2025-03-05 – 00:10 – Aurora in Central Europe

Only very briefly and only a little bit of red – but detectable down to 47°N.

DWD Webcam Lindenberg/Falkenberg southeast of Berlin (52°N, 13°E) shows some red aurora on the left side of the picture

A bit of colouring together with light pollution on the Panomax Alpine Webcam *Rax* near Vienna

2025-03-05 – Current space weather & outlook

There are currently no known CMEs travelling towards Earth. The south-east of the Sun is the most active quadrant with filament eruptions and active regions with growth – overall the Sun is quite quiet. From 8.3. (Saturday), the influence of the high-speed stream from the negatively polarised coronal hole CH21- with speeds of over 600 km/s is expected. In anticipation of the passage of a corotating interaction region CIR and the passage of the heliospheric current layer (HCS) / sector boundary crossing (SBC), G1 to G2 conditions (MINOR to MODERATE STORM) and perhaps also some aurora in Central Europe (northern horizon) seem possible.

The solar corona of the last 48 hours

2025-03-07 2200 UTC – M1.6 Flare produced a strongly southward deflected CME

The coronagraphs indicate a relatively narrow, strongly southward deflected CME, so probably no or hardly any earth-directed components. Let’s wait and see what the models calculate.

A partial halo structure can be seen in LASCO C3. We may notice slight effects of the CME on 10 March, but the main bulk will miss us to the south.

2025-03-08 – Connection with High Speed Stream begins

The timeline viewer shows the passage of the Heliospheric Current Sheet HCS / Sector Boundary Crossing SBC around 0300 UTC (Phi changes from positive to negative) together with the passage of the shock front of a Corotating Interaction Region (CIR) of the coronal hole CH21- (EPAM drops, magnetic field B buckles and then rises sharply, density N rises and falls at the moment when the velocity V starts to rise). The interplanetary magnetic field reaches strengths of 15 nT but with a currently very weak Bz component. The speed will continue to increase over the next two days (over 600 km/s possible) and longer phases with negative Bz could make auroras visible on the northern horizon.

2025-03-08 18:30 UTC – Strong magnetic convection – aurora likely

In addition to a high solar wind speed (approx. 600 km/s), a strongly southerly Bz component together with a more neutral By component is responsible for strong magnetic convection and coupling of the Earth’s magnetic field with the solar wind. Aurora later is therefore likely.