Subject: Weekly Highlights of Solar and Geomagnetic Activity, 04 - 10 September 2023

:Product: Weekly Highlights and Forecasts
:Issued: 2023 Sep 11 0151 UTC
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# Weekly Highlights and Forecasts
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Highlights of Solar and Geomagnetic Activity
04 - 10 September 2023

Solar activity ranged from low to moderate levels R1/Minor). Low
levels were observed on 04, 06 and 08-10 Sep. Moderate levels
occurred on 05 and 07 Sep. On 05 Sep, Region 3421 (N15, L=343,
class/area Eai220 on 07 Sep) produced 3 M-class flares, the largest
an M2.0/2n at 05/0812 UTC. This region also produced 21 C-class
flares. On 07 Sep, Region 3425 (N23, L=246, class/area Dai/140 on 08
Sep) produced an M2.1/1b at 07/1909 UTC. Associated with this flare
was a 1,238 sfu Type II Sweep. Region 3425 also produced 9 C-class
flares. The largest region on the disk was Region 3423 (N16, L=279,
Ekc/380 on 10 Sep). This region produced 8 C-class flares. During
the period, numerous CMEs were detected on both the front and back
side. None were determined to be Earth-directed.

The greater than 10 MeV protons at geosynchronous orbit were
slightly enhanced on 06-07 Sep due to M-class activity on 05 Sep.

The greater than 2 MeV electron flux at geosynchronous orbit reached
high levels to 1,870 pfu at 05/1550 UTC. Low to moderate levels were
observed on 04, 06-10 Sep.

Geomagnetic field activity ranged from mostly quiet to unsettled
levels on 04-10 Sep, with isolated active levels observed late on 05
Sep. Weak CME effects were observed on 04-05 Sep with weak negative
polarity CH HSS effects observed on 06-09 Sep. Total field readings,
through the period, generally averaged 5 nT with a brief peak to 11
nT observed late on 05 Sep. The Bz component reached maximum
southward readings to 10 nT late on 05 Sep. Wind speeds ranged from
highs of near 450 km/s on 04-06 Sep to lows of near 300 km/s on 10
Sep.

Forecast of Solar and Geomagnetic Activity
11 September - 07 October 2023

Solar activity is expected to be at low to moderate levels through
the forecast period. M-class flaring (R1-R2/Minor-Moderate) is
expected to dominate from 15-28 Sep when old Region 3413 (N10,
L=099) returns to the visible disk.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to be at low to moderate levels through the period.

Geomagnetic field activity is expected to be at unsettled to active
levels on 12-15, 23 and 28-30 Sep due to CH HSS activity. Mostly
quiet levels are expected on 11, 16-22, 24-27 Sep and 01-07 Oct.


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