• The ARRL Solar Report

    From ARRL de WD1CKS@VERT/WLARB to QST on Fri Feb 14 21:21:27 2025
    02/14/2025

    NOAA reports a G1 (Minor) geomagnetic Storm Watch has been issued
    for 14 Feb, 2025. A coronal hole high speed stream is expected to
    move into a position favorable for enhanced interaction between the
    high speed stream and Earth's magnetosphere. These enhancements are
    likely to cause elevated geomagnetic responses, with G1 (Minor)
    storm levels likely.

    From Spaceweather.com[1]: Another solar wind stream is heading for
    Earth. It is flowing from a canyon-like hole in the Sun's
    atmosphere. First contact with the stream on February 14th could
    cause a minor G1-class geomagnetic storm with Arctic auroras for
    Valentine's Day.

    The greatest observed 3 hr Kp over the past 24 hours was 4.ÿ The
    greatest expected 3 hr Kp for February 13 to 15 is 4.67.

    No Minor S1 or greater solar radiation storms are expected.ÿ No
    significant active region activity favorable for radiation storm
    production is forecast.

    Radio blackouts reaching the R1 levels were observed over the past
    24 hours. The largest was at February 13 at 1109 UTC.

    Solar activity is expected to be low with a chance for R1 to R2, and
    Minor to Moderate activity on February 13 to 15.

    Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
    Ionosphere - February 13, 2025, by F. K. Janda, OK1HH:

    "Total solar activity was highest last October in the current
    11-year cycle. Since then, it has been declining, but slowly. This
    is also true for flare activity. Medium strong solar flares were
    produced mainly by the active region of AR3981. Some of these were
    accompanied by CMEs, none of which hit the Earth directly, but
    passed close enough to affect its atmosphere.

    "NOAA predicted on February 8 that there was a possibility of G1
    class geomagnetic storms on February 10 and 11. The prediction
    turned out to be fairly accurate - although geomagnetic field
    activity increased as early as February 9, it was highest on
    February 10 and was elevated on February 11. Therefore, ionospheric
    shortwave propagation conditions were at their worst on 10 February
    and subsequently improved only very slowly in the following days.

    "We now observe a large coronal hole, resembling a canyon, on the
    Sun, which could be another source of enhanced solar wind. Earth
    should be hit by it on Valentine's Day, or February 14. The days
    ahead will also be rather unsettled, but the active regions now
    rising near the southeastern limb of the solar disk will cause an
    uptick in solar activity, nevertheless, causing improved propagation conditions.

    "The good news at the end: at https://www.solarham.com[2] on the bottom
    left, after an eleven-week hiatus, we can see a map of the entire
    Sun, especially the Sun's far side, under the 'Farside Watch'
    banner. So the JSOC glitch has been fixed, and after another click
    on http://jsoc.stanford.edu/data/timed[3] we can read more under the
    heading 'Time-Distance Helioseismic Far-Side Imaging.'"

    The latest report from Dr. Tamitha Skov, WX6SWW, can be found online
    at, https://youtu.be/v5H2QsbiCqo[4] .
    ÿ


    [1] http://Spaceweather.com
    [2] https://www.solarham.com
    [3] http://jsoc.stanford.edu/data/timed
    [4] https://youtu.be/v5H2QsbiCqo

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    þ Synchronet þ Whiskey Lover's Amateur Radio BBS
  • From ARRL de WD1CKS@VERT/WLARB to QST on Fri Feb 21 20:43:08 2025
    02/21/2025

    Solar activity is expected to range from low to moderate levels
    through March 15.ÿ There is a varying chance for R1 or R2 (Minor or
    Moderate) events, and a slight chance for R3 or greater events.

    Geomagnetic field activity is likely to reach G1 (Minor) levels on
    February 28, March 9, and March 12 to 14.ÿ Active levels are
    predicted for March 1. Quiet, and quiet to unsettled conditions are
    expected to prevail throughout the remainder of the period.

    The NOAA Ap Index Forecast is 5 for February 21 and 22.

    The NOAA Space Weather Prediction Center reports no space weather
    storms predicted for the next 24 hours.

    For the last 24 hours, solar flare activity has been at low levels
    with only a C-Class observed.ÿ The largest flare was a C8.1 on
    February 19.

    This flare was accompanied by a Type II radio emission and
    associated CME off the Southwest edge of the solar disk. Modelling
    efforts determined the bulk of the CME to miss ahead of Earth's
    orbit.ÿ However, a weak glancing influence cannot be ruled out late
    on February 24.
    ÿ
    Region AR3996 is the largest and most complex region on the disk but
    was responsible for only one C-Class flare. Flux emergence and an
    increase in interior spots can be seen in Region AR3998 but overall
    the region has been fairly quiet.

    Spaceweather.com[1] has an article link from the "Advancing Earth And
    Space Sciences" website concerning an extreme compression of Earth's
    magnetic field that was caused by the May 2024 solar superstorm.

    Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
    Ionosphere - February 20, 2025, by F. K. Janda, OK1HH:

    "The increase in geomagnetic activity following the decrease in
    solar activity is a simple phenomenon to explain: systems of
    magnetic field lines over active regions in the Sun open up and
    charged particles (both free electrons and the nuclei of hydrogen
    atoms, or protons themselves) slip through them more easily into
    space.

    "In Earth's orbit, we see an increase in the solar wind and,
    consequently, an increase in geomagnetic activity. At the same time,
    the ionization rate of the ionosphere is increasing, while the
    shortwave propagation conditions may not only worsen (due to
    scattering on inhomogeneities) but also improve as the MUF may grow.
    This was well known, for example, on Saturday 15 February on the
    Europe-North America route.

    "The only geomagnetically quiet days in the first half of the month
    were 3-7 February. Then the solar wind, blowing from the long
    canyon-shaped coronal hole, intensified and geomagnetic activity was
    elevated for most of the second third of February. A calm trend can
    be expected on most days of the last third of the month. Although
    there does not appear to be a significant increase in solar
    activity, it is sufficiently high. In addition, spring is
    approaching, which is good news for the state of the ionosphere."

    The predicted Planetary A Index is 5 for February 21 to 26, and 10
    on February 27.ÿ The predicted Planetary K Index is 2 on February 22
    to 26, and 3 on February 27.ÿ Predicted 10.7 cm solar flux is 170
    for February 22 to 23, 190 on February 24, 195 on February 25, 200
    on February 26, and 195 on February 27.

    Sunspot numbers for February 16 to 20, 2025 were 271, 218, 187, 119,
    and 123, with a mean of 183.6.

    ÿ


    [1] http://Spaceweather.com

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