Weekly Highlights of Solar and Geomagnetic Activity, 22 - 28 May 2023

[SWPC.We...@noaa.gov]

:Product: Weekly Highlights and Forecasts
:Issued: 2023 May 29 0142 UTC
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# Weekly Highlights and Forecasts
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Highlights of Solar and Geomagnetic Activity
22 - 28 May 2023

Solar activity was at low to moderate level. Region 3311 (N18,
L=274, class/area=Eai/470 on 24 May) produced the strongest event of
the period, an M3 (R1 - Minor) flare at 23/1213 UTC. Three other,
smaller, M-class events were also produced by the region on 22 May
and 24 May. Regions 3315 (S17, L=235, class/area=Ekc/800 on 28 May)
and 3312 (S23, L=262, class/area=Cri/070 on 22 May) also produced
M-class activity. The remaining 8 numbered active regions on the
visible disk were either quiet or only produced C-class events
during the reporting period.

Other activity included Type II radio sweeps on 22, 23 and 27 May;
however, none of the events were associated with ejecta that was
suspected to be Earth-directed.

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit reached
high levels during the entire week due higher levels of geomagnetic
activity followed by sustained elevated solar wind speeds.

Geomagnetic field activity ranged from quiet to G1 (Minor)
geomagnetic storm levels. G1 levels were observed on 22 May as
transient influence transitioned in influence from a negative
polarity CH HSS. As the HSS continued, active conditions on 23 May
further decreased to unsettled levels over 24-25 May. As solar wind
speeds returned to nominal levels on 26-27 May, the geomagnetic
field responded with quiet conditions. A minor increase to unsettled
conditions was observed on 28 May following prolonged periods of
southward Bz.

Forecast of Solar and Geomagnetic Activity
29 May - 24 June 2023

Solar activity is likely to be at low to moderate levels (R1-R2
Minor-Moderate) throughout the outlook period due to several complex
regions on the visible disk and the anticipated return of several
regions that have produced moderate level activity returning 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 range from moderate to high levels. High levels are
likely on 03-05 May, 04-10 Jun, and 19-24 Jun in response to
elevated wind speeds from multiple, recurrent CH HSSs. The remainder
of the outlook period is likely to be at moderate levels.

Geomagnetic field activity is expected to range from quiet to G1
(Minor) geomagnetic storm conditions. G1 conditions are likely on 02
Jun and 18 Jun; active conditions are likely on 29 May, 03-04 Jun,
and 19-20 Jun; unsettled conditions are likely on 30 May, 05-06 Jun,
and 21 Jun. All elevated levels of geomagnetic field activity are in
response to multiple, recurrent CH HSSs. Quiet conditions are
expected for the remainder of the outlook period.