Subject: Weekly Highlights of Solar and Geomagnetic Activity, 10 - 16 April 2023

:Product: Weekly Highlights and Forecasts
:Issued: 2023 Apr 17 0333 UTC
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# Weekly Highlights and Forecasts
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Highlights of Solar and Geomagnetic Activity
10 - 16 April 2023

Solar activity ranged from low to moderate levels. Moderate levels
were reached on 10, 11, and 14 Apr due to M-class flaring from
Regions 3272 (S21, L=102, class/area Eai/280 on 09 Apr), 3276 (S20,
L=050, class/area Dao/80 on 11 Apr), and 3282 (N11, L=024,
class/area Eki/530 on 16 Apr). These included an M2 at 10/0520 UTC
from Region 3276, an M1/1n at 11/1016 UTC from Region 3272, and a
pair of M1 flares at 14/1618 UTC and 14/2327 UTC from Region 3282.
The period began with initially two numbered spot groups, but grew
to nine spotted regions by the end of the period.

Other activity included multiple filament eruption and CMEs. The
majority of the CMEs were determined to not be Earth-directed.
However, a slow moving partial halo CME was observed at 16/0125 UTC
in SOHO/LASCO C2 imagery associated with a filament eruption near
N20W40 at 15/2300 UTC in SUVI 304 imagery. Modelling and analysis of
this event indicated the potential for a weak glancing blow on 22
Apr.

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit was at
normal to moderate levels throughout the period.

Geomagnetic field activity ranged from quiet to active levels. Solar
wind parameters began with a solar sector boundary crossing around
10/0620 UTC followed by the onset of a positive polarity coronal
hole high speed stream (CH HSS). Solar wind speeds increased to
around 530 km/s by midday on 10 Apr before decreasing to near
nominal levels by late on 11 Apr. Weaker positive polarity CH HSS
conditions occurred on 14-15 Apr. The geomagnetic field responded
with quiet to active levels on 10 Apr, quiet to unsettled levels on
11, 13-15 Apr, and quiet conditions on 12 and 16 Apr.

Forecast of Solar and Geomagnetic Activity
17 April - 13 May 2023

Solar activity is expected to remain at low levels with a chance for
M-class (R1-R2, Minor-Moderate) flares and a slight chance for
X-class (R3-Strong) flares on 17-25 Apr and again on 08-13 May due
to the flare potential of Region 3282.

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 23 Apr-06 May due CH HSS influence.

Geomagnetic field activity is expected to reach unsettled to active
levels on 21-22 Apr due to a combination of a glancing blow from the
16 Apr CME and the onset of a negative polarity CH HSS. Unsettled to
active levels are again expected on 26 Apr-04 May, 07 May, and 11-12
May with G1 (Minor) storm levels likely on 26-28 Apr and 30 Apr due
to recurrent CH HSS activity.


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