Subject: Weekly Highlights of Solar and Geomagnetic Activity, 24 - 30 March 2025

:Product: Weekly Highlights and Forecasts
:Issued: 2025 Mar 31 0224 UTC
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# Weekly Highlights and Forecasts
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Highlights of Solar and Geomagnetic Activity
24 - 30 March 2025

Solar activity was low on 24-25 Mar, moderate on 26-27 Mar and 29
Mar, and high on 28 Mar and 30 Mar. High levels were reached on 28
Mar as the strongest event of the period, an X1.1 (R3-Strong) flare
at 28/1521 UTC from yet-to-be-numbered Region 4046 (N05, L=301, class/area=Dho/270 on 30 Mar), was produced on the Sun's eastern
limb. Associated with the event was a Type IV radio sweep and a
Tenflare (380 sfu). The resulting fast-moving CME was analyzed and
modelled. The results suggested the far flank of the CME would pass
close, but ultimately miss Earth. High solar activity levels were
again reached on 30 Mar due to frequent R1 flares from Region 4048
(S15, L=281, class/area=Eki/300 on 30 Mar). A total of six events
were observed, the largest of which was an M1.6 (R1) flare at
30/1642 UTC.

Other activity included Type II radio sweeps on 25 Mar and 26 Mar.
Both of these events were associated with non-Earth-directed CME
events on or beyond the W. limb.

No proton events were observed at geosynchronous orbit. However, an
increase above background was observed two days after the X1.1 flare
at 28/1521 UTC from the Sun's eastern limb. Although delayed,
the rise in proton flux is likely related to this event.

The greater than 2 MeV electron flux at geosynchronous orbit climbed
to high levels on 27-30 Mar. This increase in electron flux was
caused by the influence of a strong, positive polarity CH HSS, which
began around 26 Mar.

Geomagnetic field activity ranged from quiet to G2 (Moderate)
geomagnetic storms. Active conditions on 24 Mar were associated with
the passage of a CME that left the Sun on 21 Mar. On 25 Mar active
conditions were again observed due to the onset of CIR ahead of a
positive polarity CH HSS. Geomagnetic activity increased to G2
(Moderate) levels on 26 Mar as total magnetic field strength reached
a brief peak of 29 nT and the Bz component reached as far south as
-27 nT. Wind speeds increased from above ~600 km/s on 26 Mar to
above ~800 km/s on 27 Mar. The geomagnetic field responded with a
mix of active to G1 (Minor) storm conditions. As total magnetic
field strength and solar wind speeds declined on 28 Mar, geomagnetic
conditions decreased to mostly unsettled to active levels. During
the final waning stage of the positive polarity CH, an isolated
period of active was last observed early on 29 Mar and only quiet
conditions were observed over 30 Mar.

Forecast of Solar and Geomagnetic Activity
31 March - 26 April 2025

Solar activity will continue at a chance for R1-R2 (Minor-Moderate)
throughout the outlook period due to multiple complex regions on the
visible disk as well as on the Sun's farside that are likely to
return. A slight chance exists for R3 (Strong) events over the next
three days primarily due to the flare potential from complex regions
in the Sun's eastern hemisphere.

No proton events are expected at geosynchronous orbit are likely to
remain below the S1 (Minor) solar radiation storm threshold (>10
MeV proton flux of 10 pfu).

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to be at high levels on 31 Mar, 06-14 Apr, and 23-26 Apr in
response to multiple, recurrent, CH HSSs. The remainder of the
outlook period is expected to be at normal to moderate levels.

Geomagnetic field activity is expected to range from quiet to G2
(Moderate) geomagnetic storm conditions. G2 conditions are likely on
05 Apr and 09 Apr; G1 (Minor) conditions are likely over 04 Apr, 08
Apr, and 10 Apr, active conditions are likely over 11 Apr, 13 Apr,
and 21-24 Apr; unsettled conditions are likely on 03 Apr, 06-07 Apr,
12 Apr, 14-15 Apr, 17-20 Apr, and 25-26 Apr. All increases in
geomagnetic activity are anticipated in response to multiple,
recurrent, CH HSSs. The remainder of the outlook period is likely to
mostly quiet.


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* Origin: NOAA Space Weather Prediction Center (3:633/280.2@fidonet)