• Weekly Highlights of Solar and Geomagnetic Activity, 13 - 19 March 2023

    From SWPC.Webmaster@noaa.gov@21:1/5 to All on Mon Mar 20 13:00:13 2023
    XPost: rec.radio.amateur.space, rec.radio.shortwave, rec.radio.info

    :Product: Weekly Highlights and Forecasts
    :Issued: 2023 Mar 20 0234 UTC
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    # Weekly Highlights and Forecasts
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    Highlights of Solar and Geomagnetic Activity
    13 - 19 March 2023

    Solar activity reached moderate levels on 17 Mar due to an M1/Sn
    flare (R1 - Minor) at 17/1507 UTC from Region 3247 (S24, L=162, class/area=Cao/100 on 08 Mar). The other 17 numbered active regions
    on the visible disk only produced low levels of solar activity
    during the summary period. Other activity included many filament
    eruptions but only a DSF on ~17/0930 UTC, centered near S40W38, was
    modeled and thought to have an Earth-directed component. Model
    output suggested anticipated onset of the CME to be late on 20 Mar
    to early on 21 Mar. Lastly, a Type IV radio sweep was observed in
    conjunction with an impulsive C9/1n 18/0716 UTC flare from Region
    3256 (S22, L=004, class/area=Eko/270 on 19 Mar).

    The greater than 10 MeV proton flux reached S1 (Minor) levels on 13
    Mar. The enhancement was associated with a full-halo CME first
    observed in SOHO/LASCO C2 imagery beginning near 13/0336 UTC. The
    energetic event was determined to be associated with activity on the
    far-side of the Sun but still was able to produce significant
    enhancements in relativistic proton flux on the GOES-16 satellite.
    S1 conditions were reached again on 14 Mar, with an additional
    enhancement associated with a shock ahead of a CME that would arrive
    on 15 Mar that would increase 10 MeV protons back above the S1
    threshold to an eventual peak flux of 22 pfu at 15/0425 UTC. After
    shock passage, the >10 MeV proton flux quickly decreased, with
    the last observation above the S1 threshold observed at 15/0530 UTC.

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

    Geomagnetic field activity range from quiet to G2 (Moderate)
    geomagnetic storm levels. G2 conditions were observed on 15 Mar in
    response to influence from a CMEs that left the Sun over 11 and 12
    Mar. Total magnetic field strength (Bt) increased from 8 nT 18 nT
    during the shock at 15/0347 UTC. With the shock, wind speeds
    increased from ~425 km/s to ~525 km/s. Bt reached a peak of 24-25 nT
    shortly after and solar wind speeds were recorded at ~570 km/s
    before both speeds and Bt underwent a gradual decline. Weaker
    activity, also associated with transient activity produced active
    conditions on 14 Mar and 16 Mar. Mostly quiet to unsettled
    conditions were observed on 17-19 Mar and only quiet conditions were
    observed on 13 Mar.

    Forecast of Solar and Geomagnetic Activity
    20 March - 15 April 2023

    Solar activity is expected to be at low levels with a chance for
    R1-R2 (Minor-Moderate) events. This is due to the flare potential of
    regions both currently on the visible disk and significant regions
    expected to return to the visible disk from the far-side of the Sun
    over the outlook period.

    No proton events are expected at geosynchronous orbit.

    The greater than 2 MeV electron flux at geosynchronous orbit is
    expected to range from moderate to high levels. High levels are
    likely on 26-29 Mar and 31 Mar - 06 Apr due to multiple, recurrent
    CH HSSs. The remainder of the outlook period is likely to be at
    normal to moderate levels.

    Geomagnetic field activity is expected to be at quiet to G2
    (Moderate) geomagnetic storm levels. G2 conditions are likely on 25
    Mar; G1 (Minor) conditions are likely on 26 Mar and 30-31 Mar;
    active conditions are likely on 20-21 Mar, 01-02 Apr and 10-11 Apr;
    unsettled conditions are likely on 24 Mar, 27-28 Mar, 03-04 Apr, 12
    Apr and 14-15 Apr. With the exception of 20-21 Mar, which is
    expected to include possible transient influence as well, all
    anticipated enhancements in geomagnetic conditions are in response
    to multiple, recurrent CH HSSs. The remainder of the outlook period
    is expected to be at mostly quiet levels.

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