• Weekly Highlights of Solar and Geomagnetic Activity, 18 - 24 September

    From SWPC.Webmaster@noaa.gov@21:1/5 to All on Mon Sep 25 13:00:09 2023
    XPost: rec.radio.amateur.space, rec.radio.shortwave, rec.radio.info

    :Product: Weekly Highlights and Forecasts
    :Issued: 2023 Sep 25 0237 UTC
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    # Weekly Highlights and Forecasts
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    Highlights of Solar and Geomagnetic Activity
    18 - 24 September 2023

    Solar activity was at low levels on 18 Sep, moderate levels on 19,
    22-24 Sep, and high levels on 20-21 Sep. In total, ten R1 (Minor)
    events and two R2 (Moderate) events were registered throughout the
    period. Region 3435 (N10, L=102, class/area=Dki/300 on 24 Sep)
    produced two M8 flares at 20/1419 UTC and at 21/1254 UTC, along with
    four R1 events over 19-22 Sep. CMEs associated with flare activity
    on 20-21 Sep were predicted to arrive on 23 Sep, but ultimately
    missed. A CME associated with a long-duration M1.2 flare at 22/0336
    UTC from Region 3435 resulted in an Earth-directed CME that arrived
    on 24 Sep. A CME associated with a filament eruption centered near
    N36W05 at 22/0645 UTC was modelled and was predicted to arrive on
    24-25 Sep. Region 3443 (N28, L=147, class/area=Dki/260 on 23 Sep)
    produced four R1 events on 22 and 24 Sep. A CME associated with
    flare activity from Region 3435 at 22/2233 UTC was modelled and is
    likely to arrive on 26 Sep.

    No proton events were observed at geosynchronous orbit, though a
    minor enhancement was observed on 24 Sep.

    The greater than 2 MeV electron flux at geosynchronous orbit reached
    moderate levels on 18 Sep, and high levels on 19-24 Sep.

    Geomagnetic field activity reached G1 (Minor) storm levels on 18 Sep
    due to residual effects of a CME from 14 Sep. G3 (Strong) storm
    levels were observed on 19 Sep, and active conditions were observed
    on 20 Sep, due to the passage of a CME from 16 Sep. Quiet to
    unsettled conditions were observed over 21-23 Sep. G2 (Moderate)
    storms were observed on 24 Sep due to the arrival of a CME from 22
    Sep.

    Forecast of Solar and Geomagnetic Activity
    25 September - 21 October 2023

    Solar activity is expected to be low to moderate with M-class flare
    activity likely through much of the 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 25-28 Sep, and moderate levels
    throughout the remainder of the outlook period.

    Geomagnetic field activity is expected to reach G1-G2
    (Minor-Moderate) storm levels on 25 Sep due to the passage of a CME
    from early on 22 Sep. Active levels are expected on 26 Sep due to
    residual CME effects in addition to the predicted glancing-blow
    arrival of a CME from late on 22 Sep. Quiet conditions are expected
    to prevail throughout the remainder of the period.

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