Subject: Weekly Highlights of Solar and Geomagnetic Activity, 27 November - 03 December 2023

:Product: Weekly Highlights and Forecasts
:Issued: 2023 Dec 04 0331 UTC
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# Weekly Highlights and Forecasts
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Highlights of Solar and Geomagnetic Activity
27 November - 03 December 2023

Solar activity reached high levels on 28 Nov when Region 3500 (S20,
L=307, class/area=Dkc/320 on 27 Nov) produced an M3.4 flare
(R1/Minor) at 28/1932 UTC, followed by an M9.8 flare (R2/Moderate)
at 28/1950 UTC; the largest event observed during the period. The
asymmetric halo CME associated with the M9.8 flare, visible in
LASCO/C2 coronagraph imagery at 28/2012 UTC, arrived at Earth on 01
Dec. Solar activity reached moderate levels on 01 Dec with M1 flares
observed at 01/0439 UTC and 01/2120 UTC from Regions 3502 (N14,
L=343, class/area=Cao/80 on 27 Nov) and 3500, respectively. Solar
activity was at low levels with C-class flare activity observed over
27, 29-30 Nov, and 02-03 Dec.

Solar activity was low on 27 Nov, however, three distinct CMEs
associated with four prominent eruptions were analyzed to have
partial Earth-directed components. The first 27 Nov CME, visible in
LASCO/C2 imagery at 27/0624 UTC off the SSW, was associated with a
filament eruption near S26W27 at 27/0531 UTC (in SUVI 304 imagery).
The second CME, visible in C2 imagery at 27/2000 off the SE, was
associated with a C3.8 flare at 27/1837 UTC from an unnumbered area
of flux near N20E15. The third CME, visible in C2 imagery at 27/2336
off the NW, was believed to be associated with a C5.5 flare at
27/2340 UTC from Region 3503 (N15, L=284, class/area=Hrx/10 on 27
Nov) and a filament eruption that occurred at around the same time
just northward of 3503.

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 was quiet under background solar wind
conditions on 27 Nov through late 30 Nov. The solar wind environment
became weakly enhanced at around 30/2330 UTC due to the arrival of
CME(s) from 27 Nov. Active conditions were observed in the early
hours of 01 Dec following CME arrival. An additional, stronger,
solar wind enhancement was observed at 01/0853 UTC due to the
arrival of a CME from 28 Nov. Periods of G1-G3 (Minor-Strong)
geomagnetic storming were observed following CME arrival on 01 Dec,
and active and G1 levels were observed in the early hours of 02 Dec
as CME influences waned. Quiet and unsettled levels were observed on
03 Dec.

Forecast of Solar and Geomagnetic Activity
04 December - 30 December 2023

Solar activity is expected to be low with a chance for M-class flare
activity (R1-R2/Minor-Moderate) throughout the outlook period.

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 05-09 Dec. Normal to moderate
levels of flux are expected throughout the remainder of the period.

Geomagnetic field activity is likely to reach G2 (Moderate) storm
levels on 04 Dec, G1 (Minor) levels on 05 Dec, and active levels on
06 Dec, in response to negative polarity CH HSS influences. Active
conditions are likely on 12 Dec due to positive polarity CH HSS
influences. Periods of G1 storms are likely on 18-19 and 22 Dec,
with active levels likely on 23 Dec, due to the influences of
positive polarity CH HSSs. Quiet and quiet to unsettled levels are
expected to persist throughout the remainder of the period.


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