• Weekly Highlights of Solar and Geomagnetic Activity, 31 July - 06 Augus

    From SWPC.Webmaster@noaa.gov@21:1/5 to All on Mon Aug 7 13:00:10 2023
    XPost: rec.radio.amateur.space, rec.radio.shortwave, rec.radio.info

    :Product: Weekly Highlights and Forecasts
    :Issued: 2023 Aug 07 0249 UTC
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    # Weekly Highlights and Forecasts
    Highlights of Solar and Geomagnetic Activity
    31 July - 06 August 2023

    Solar activity ranged from moderate to high levels. 20 events above
    the M-class threshold (R1-Minor) were observed during the summary
    period. High solar activity levels were observed on 01 Aug due to
    eight M-class (R1-Minor) events from Region 3380 (S10, L=125, class/area=Dkc/430 on 02 Aug) and again on 02 Aug due to four
    M-class (R1) flares from the same region and a fifth M-class flare
    from Region 3386 (N12, L=092, class/area=Dki/360 on 28 Jul). Region
    3386 also caused high levels over 05 Aug, with an X1.6/2b flare
    (R3-Strong) at 05/2221 UTC, the strongest during the week, and an
    over 06 Aug with an M5.5/Sn flare (R2-Moderate) at 06/1840 UTC. Type
    II and Type IV radio sweeps were observed with CME activity on 02
    Aug from flare activity from Region 3386. Additional Type II radio
    sweeps were produced by the same region twice on 05 Aug. Solar
    activity for the remainder of the summary period was at moderate

    Activity associated with Region 3386 produced significant eruptions
    that resulted in CMEs thought to contain Earth-directed components
    occurred over 01-02 Aug and 05-06 Aug. An M1.3/1f flare at 02/0812
    UTC was associated with a CME first seen in SOHO/LASCO C2 imagery
    beginning 02/0936 UTC; an M1.6/1n flare at 05/0718 UTC, which also
    resulted in the elevation of high energy proton flux levels (>10
    MeV) with CME first seen in C2 imagery at 05/0700 UTC, and an
    X1.6/2b flare at 05/2221 UTC, which produced an additional
    enhancements to high energy proton flux levels and associated CME
    first seen in C2 at 05/2236 UTC.

    An S1 (Minor) proton event was observed over 05-06 Aug a
    long-duration M1.6/1n flare from Region 3386. The GOES-16 greater
    than 10 MeV proton flux exceeded S1 threshold at 05/115 UTC. The
    event reached peaked of 18.5 pfu at 05/1745 UTC. Flux levels dropped
    below the S1 threshold near the end of the 05 Aug UT day; however,
    an additional rise above the S1 threshold was observed following the
    X1.6/2b flare at 05/2221 UTC from Region 3386. The S1 then event
    continued until 06/0455 UTC.

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

    Geomagnetic field activity ranged from quiet to G3 (Strong)
    geomagnetic storm conditions. Quiet conditions on 31 Jul increased
    to unsettled levels on 01 Aug and further to active levels on 02 Aug
    in response to transient influence from a CME that left the Sun on
    28 Jul. Total magnetic field strength increased to a peak of 12 nT
    and the Bz component reached as far south as -9 nT. Solar wind
    speeds were ~400 km/s during the transient. Geomagnetic activity
    decreased to unsettled levels over 03 Aug before another increase to
    active levels was observed 04 Aug in response to the onset more
    transient influence from activity on the Sun over 01-02 Aug. A peak
    in geomagnetic activity of G3 conditions was observed on 07 Aug
    following an interplanetary shock, observed at L1 at 05/0207 UTC.
    Total magnetic field strength increased from 10 nT to 25 nT and Bz
    reached as far south as -21 nT. Geomagnetic activity decreased
    rapidly after 05/1200 UTC as the Bz component of the IMF rotated far
    north resulting in mostly quiet conditions through the remainder of
    the reporting period.

    Forecast of Solar and Geomagnetic Activity
    07 August - 02 September 2023

    Solar activity is likely to reached moderate levels on 07 Aug,
    primarily due to the remaining flare potential of Region 3386 as it
    continues to rotate just beyond the W limb. Mostly low solar
    activity is expected for the rest of the outlook period, with a
    chance for M-class (R1-R2/Minor-Moderate) activity after 17 Aug as
    multiple active regions that have produced significant flare
    activity are expected to return to the visible disk from the
    Sun's farside.

    There is a chance for proton events (S1-Minor) at geosynchronous
    orbit over the next three days due to potential activity from Region
    3386 just beyond the Sun's W limb.

    The greater than 2 MeV electron flux at geosynchronous orbit is
    expected to be at mostly moderate levels with the exception of high
    levels on 27-28 Aug due to anticipated positive polarity CH HSS

    Geomagnetic field activity is expected to reach active levels on 07
    Aug due to CME influence from activity on the Sun over 04 Aug. An
    increase to G1 (Minor) geomagnetic storm levels is likely on 08 Aug
    from eruptive activity on the Sun over 05 Aug. A decrease to active
    levels is expected on 09 Aug with waning transient influence
    transitioning to influence from a weak, positive polarity CH HSS.
    Active conditions are again likely on 26 Aug due to a recurrent CH
    HSS. The remainder of the outlook period is likely to be at mostly
    quiet levels.

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