:Product: Weekly Highlights and Forecasts
:Issued: 2025 May 26 0140 UTC
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# Weekly Highlights and Forecasts
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Highlights of Solar and Geomagnetic Activity
19 - 25 May 2025

Solar activity ranged from low to high levels. Region 4098 (S04,
L=021, class/area=Dai/170 on 25 May) produced the strongest event of
the period, an impulsive X1.1 flare (R3-Strong) at 25/0152 UTC. An
associated Tenflare (170 sfu) and subsequent, narrow CME was
observed. The CME was oriented far to the west and no expected to
contain an Earth-directed component. The region also produced an
impulsive M8.9/2b (R2-Moderate) event at 25/1630 UTC. Region 4087
(N15, L=057, class/area=Dso/240 on 18 May) was the only other region
to produce an event above R1 (Minor) with an M1.2/Sn flare at
21/0008 UTC.

No Earth-directed CMEs were observed in available coronagraph
imagery.

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit reached
high levels on 18-19 May and 21-24 May in response to a high-speed
stream from a large, polar-crown-connected coronal hole. 20 May and
25 May electron flux was at normal to moderate levels.

Geomagnetic field activity was at quiet to unsettled over 19-20 May.
An isolated period of active conditions were observed on 21 May.
Quiet conditions were observed over 22-25 May. The solar wind was
under the influence of a positive polarity CH HSS for the week.
Solar wind speeds reached of peak of ~630 km/s on 21 May and
gradually waned over the following days.

Forecast of Solar and Geomagnetic Activity
26 May - 21 June 2025

Solar activity is likely to reach moderate levels
(R1-R2/Minor-Moderate), with a chance for R3 (Strong), over the next
three days as Region 4098 (S04, L=021, class/area=Dai/170 on 25
May), the most productive region on the visible disk, makes its way
to the west limb of the Sun. A chance for M-class X-ray activity
(R1-R2) will persist throughout the outlook period due to multiple
regions on the visible as well as multiple active regions scheduled
to return from the farside of the Sun.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to be at high levels on 30 May - 05 Jun and 14-21 Jun
following recurrent coronal hole influence. The remainder of the
period is expected to be at normal to moderate levels.

Geomagnetic field activity is expected to be at mostly elevated due
to anticipated influence from multiple, recurrent coronal holes. G1
(minor) geomagnetic storms are likely on 13-14 Jun; active
conditions are likely over 28-29 May, 02 Jun, 05 Jun, 10-11 Jun, and
15-17 Jun; unsettled conditions are likely over 26-27 May, 30 May -
01 Jun, 03-04 Jun, 06-07 Jun, and 18-21 Jun. Quiet conditions are
only expected on 08-09 Jun.


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