Weekly Highlights of Solar and Geomagnetic Activity, 18 - 24 December 2023

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

:Product: Weekly Highlights and Forecasts
:Issued: 2023 Dec 25 0302 UTC
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# Weekly Highlights and Forecasts
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Highlights of Solar and Geomagnetic Activity
18 - 24 December 2023

Solar activity was at low to moderate (R1-Minor) levels over the
past week. Moderate levels were observed on 21-22 Dec and 24 Dec.
The strongest event was an M4.2/1n flare (R1) at 21/0538 UTC from
Region 3519 (S12, L=71, class/area=Dai/180 on 21 Dec). Other, lower,
M-class (R1) events were observed from Region 3529 (S19, L=345,
class/area=Dko/450 on 20 Dec) and event from just beyond the SE limb
on 24 Dec. The other 18 numbered active regions either produced only
C-class activity or were relatively quiet.

Other activity included a ~22 degree filament eruption, centered
near N48W35, that began around 24/0920 UTC. A subsequent CME
signature was observed in SOHO/LASCO C2 imagery at 24/1224 UTC.
Another CME from a filament eruption, centered near S20E48, was
observed after 24/1438 UTC. Modeling of the two events suggested
potential glancing blow late on the 27th and in to the 28th of Dec.
No other Earth-directed CMEs were identified 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 21-22 Dec due to elevated geomagnetic activity
earlier in the week. The remainder of the period was at normal to
moderate levels.

Geomagnetic field activity ranged from quiet to G2 (Moderate)
geomagnetic storm levels. G2 conditions observed on 28 Dec were in
response to the waning portion of a CME that left the Sun over 14-15
Dec. Solar wind speeds were just under 500 km/s and the Bz component
was near -10 nT around the time of the activity. Conditions
decreased to active levels as transient influence weakened over
19-20 Dec. Mostly quiet to unsettled levels were observed for the
remainder of the week (21-24 Dec).

Forecast of Solar and Geomagnetic Activity
25 December - 20 January 2024

Solar activity is expected to be at low levels, with a chance for
moderate levels (R1-R2/Minor-Moderate), throughout the outlook
period. Increased potential for activity is due to multiple R1 event
or greater producing regions either on the visible disk or due to
return in the coming weeks.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to be reach high levels over 31 Dec - 05 Jan and 09-12 Jan
due to multiple anticipated 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 active
levels. Active levels over 27-28 Dec are due to potential CME
influence. Active conditions on 30 Dec and unsettled conditions on
31 Dec - 02 Jan and 08-10 Jan are likely due to anticipated
influence from multiple, recurrent CH HSSs. The remainder of the
outlook period is likely to be mostly quiet.