XPost: rec.radio.amateur.space, rec.radio.shortwave, rec.radio.info

:Product: Weekly Highlights and Forecasts
:Issued: 2025 Jun 30 0550 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
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# Weekly Highlights and Forecasts
#
Highlights of Solar and Geomagnetic Activity
23 - 29 June 2025

Solar activity was at low levels through the week. The largest flare
was a C5.0 at 23/1223 UTC from Region 4115 (N21, L=019, class/area
Dso/180 on 12 Jun). Regions 4117(S14, L=303, class/area Dai/210 on
19 Jun), 4118 (S12, L=293, class/area Dai/120 on 23 Jun), 4120 (N07,
L=298, class/area Dai/090 on 26 Jun) and 4122 (N13, L=219,
class/area Dai/140 on 28 Jun) were the largest regions on the disk
this week, however only 4118 and 4120 had beta-gamma magnetic
classifications briefly. Other activity included a C4.0/1f flare at
28/1954 UTC from Region 4126 (N07, L=261, class/area Cro/020 on 28
Jun). An associated, faint, partial-halo CME was observed at 28/2112
UTC in SOHO/LASCO C2 imagery. Modelling of the event showed an
arrival early on 02 Jul.

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit reached
high levels on 23-25 Jun and again on 27-29 Jun with a peak flux of
6,350 pfu observed at 29/1600 UTC.

Geomagnetic field activity ranged from quiet to G1 (Minor) storming.
Solar wind parameters began the period enhanced but waning under
positive polarity CH HSS influence. Solar wind speeds decreased from approximately 400 km/s by early on 24 Jun. At 24/0930 UTC, a solar
sector boundary crossing was observed as the solar wind transitioned
into a negative sector. By early on 25 Jun, a CIR preceding a
negative polarity CH HSS was observed. Total field began to increase
early on 25 Jul reaching a maximum of 16 nT at 25/2010 UTC followed
by an increase in solar wind speed mostly in the 650-750 range, with
multiple readings over 800 km/s. Solar wind speeds slowly decreased
on 28-29 Jun and ended the period near 470 km/s. The geomagnetic
field responded with quiet to unsettled levels on 23-24 Jun, quiet
to active levels on 25 Jun, unsettled to G1 (Minor) storming on
26-27 Jun, and back to quiet to unsettled levels on 28-29 Jun.

Forecast of Solar and Geomagnetic Activity
30 June - 26 July 2025

Solar activity is expected to be at low levels on 30 Jun - 04 Jul.
Moderate (R1-R2, Minor-Moderate) levels are likely on 05 Jul - 26
Jul with the return of old Regions 4114 (N21, L=035) and 4117 on 05
Jul and 12 Jul, respectively.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to reach high levels on 30 Jun -01 Jul, 03 -08 Jul, and
again on 20-26 Jul due to recurrent CH HSS influence.

Geomagnetic field activity is expected to reach unsettled to active
levels with G1 (Minor) geomagnetic storming likely on 02-03 Jul with
the arrival of the 28 Jun CME. Unsettled to active levels are
expected on 04-09, 11-19, 22-25 Jul with G1 (Minor) storming likely
on 23-24 Jul due to recurrent CH HSS activity.

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