• Weekly Highlights of Solar and Geomagnetic Activity, 29 April - 05 May

    From SWPC.Webmaster@noaa.gov@21:1/5 to All on Mon May 6 13:00:09 2024
    XPost: rec.radio.amateur.space, rec.radio.shortwave, rec.radio.info

    :Product: Weekly Highlights and Forecasts
    :Issued: 2024 May 06 0628 UTC
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    # Weekly Highlights and Forecasts
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    Highlights of Solar and Geomagnetic Activity
    29 April - 05 May 2024

    Solar activity was at moderate to high levels. Moderate levels were
    observed on 29 Apr and 01-02 May. High levels were reached on 30
    Apr, due in part to an M9.5/2b flare at 30/2346 UTC from Region 3654
    (S07, L=134, class/area Fkc/550 on 30 Apr). Region 3654 was the
    largest and most complex spot group on 28 Apr-01 May, however it was
    in decay as it approached the SW limb on 01 May. The region produced
    a total of 11 M-class flares. On 30 Apr, Region 3663 (N26, L=037,
    class/area Fkc/580 on 05 May) emerged in the NE quadrant, followed
    by Region 3664 (S19, L=352, class/area Ekc/580 on 05 May) on 01 May.
    Both regions grew steadily over the following days. Region 3663
    produced 17 M-class flares and 3 X-class flares while Region 3664
    produced only 5 M-class flares. The three X-class flares included an
    X1.6/1b at 03/0222 UTC, an X1.3/1b at 05/0601 UTC, and an X1.2/1b at
    05/1154 UTC. The X1.6 flare had associated Type II (959 km/s) and IV
    radio sweeps, a 550 sfu Tenflare and an associated CME first
    observed in SOHO/LASCO C2 imagery at 03/0248 UTC. Modelling of the
    event showed a potential glancing blow arriving around 05/1800 UTC.
    There were two further CME runs of note. Those included an eruption
    near N13W09 at 29/0909 UTC that displayed a westward flow across
    GOES 16 SUVI imagery. C2 imagery showed a CME off the NW limb at
    29/1248 UTC that was modelled as a potential glancing blow on 03 May
    around 1500 UTC. Lastly, a CME that was associated with a C3.9 flare
    at 03/2037 UTC from a plage area in the NE quadrant. The flare had
    associated Type II (392 km/s) and Type IV radio emissions and a CME
    first observed in C3 imagery at 03/2218 UTC. Analysis showed a
    potential glancing blow on 09 May. Other eruptive events associated
    with radio signatures were observed, but did not produce ejecta
    determined to be on the Sun-Earth line.

    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.

    Solar wind parameters began the period under mild positive polarity
    CH HSS influence solar wind speed was mostly in the 450-500 km/s
    range and total field around 2-4 nT. Solar wind speed began to
    diminish to nominal levels on 30 Apr. After 30/1130 UTC, the first
    of three CMEs were observed. Total field increased to near 14 nT
    while the Bz component rotated from -9 nT to +13 nT. Solar wind
    speed continued to decrease to near 350 km/s. The geomagnetic field
    responded with quiet levels on 29 Apr, followed by quiet to active
    levels on 30 Apr-01 May. On 02 May, a shock arrival was observed at
    02/1317 UTC, indicating the arrival of the second CME. This CME was
    possibly the one that left the Sun on 29 Apr. The IMF increased to approximately 21 nT and the Bz component shifted southward to -19
    nT. Solar wind speed increased initially to near 450 km/s and later
    to near 510 km/s on 03 May. The geomagnetic field responded with
    unsettled to G3 (Strong) storm levels on 02 May and quiet to active
    levels on 03 May. By early on 03 May, the IMF had decreased to
    nominal levels with solar wind speed slowly returning to background
    conditions. Nominal conditions returned on 04 May and through the
    midday on 05 May. Around 05/1500 UTC, another enhancement was
    observed in the IMF, likely the arrival of the 03 May CME. Total
    field strength increased gradually to 14 nT while the Bz component
    reached a southward deflection of -12 nT. Solar wind speed increased
    to near 380 km/s. The geomagnetic field responded with unsettled to
    active levels late on 05 May.

    Forecast of Solar and Geomagnetic Activity
    06 May - 01 June 2024

    Solar activity is expected to be at moderate to high levels (R1-R3/Minor-Strong) through 12 May as Regions 3663 and 3664 rotate
    across the visible disk. Low to moderate levels are expected on 12
    May-01 Jun.

    There is a chance for S1-S2 (Minor-Moderate) solar radiation storm
    levels on 06-13 May due to the flare potential of Regions 3663 and
    3664.

    The greater than 2 MeV electron flux at geosynchronous orbit is
    expected to be at normal to moderate levels on 06 May-01 Jun.

    Geomagnetic field activity is expected to be at unsettled to G2
    (Moderate) storm levels on 06 May due to persistent CME influence.
    The geomagnetic field is expected to reach unsettled to active
    levels on 07-09 May, 12-14 May, 23-25 May, 27-28 May, and 31 May-01
    Jun due to recurrent CH HSS activity.

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