• The ARRL Solar Update

    From ARRL de WD1CKS@VERT/WLARB to QST on Friday, March 06, 2026 18:15:00
    03/06/2026

    Solar activity continued at low levels with isolated C-class
    flaring. Regions 4381 and 4384 remained the primary drivers of
    activity. The largest event of the period was a C2.9 flare from
    Region 4381 on March 3. Region 4384 continues to rotate further onto
    the disk, but foreshortening still hinders a definitive
    characterization of its magnetic complexity. Region 4378 showed some
    new flux emergence but remained mostly inactive.
    ÿ
    Region 4383 simplified into a unipolar group following the loss of
    its trailing spots, while Region 4380 decayed to plage. No
    Earth-directed coronal mass ejections (CMEs) were observed in
    available coronagraph imagery.
    ÿ
    Solar activity is expected to be at low levels, with a chance for
    isolated M-class activity (R1-R2/minor-moderate) through March 6.

    A brief description of Sunspots can be found on the Space Weather
    Prediction Center website at, https://www.swpc.noaa.gov/phenomena/sunspotssolar-cycle[1] .
    ÿ
    Solar wind parameters reflected the onset of a positive polarity
    coronal hole high-speed stream (+CH HSS). Solar wind speed increased
    to 450 km/s. Solar wind parameters are expected to remain enhanced
    due to the ongoing influence of the +CH HSS. Residual enhancements
    are likely to persist, keeping conditions slightly above background
    levels before another enhancement is expected with the onset of a
    negative polarity coronal hole high-speed stream (-CH HSS).ÿ Active
    conditions are expected on March 7 and 8 as high-speed stream
    influences continue.

    Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
    Ionosphere, March 5, 2026, by F. K. Janda, OK1HH:

    "Overall solar activity declined, with the number of sunspot groups
    ranging between three and six over the past week. Their magnetic
    configuration was simple, so no significant flares on the solar disk
    was observed.

    "However, the solar flux remained at a relatively high level of
    130-148 s.f.u., which, together with a decrease in geomagnetic
    activity (no major disturbances, just alternating calm and
    moderately active days), resulted in improved conditions for
    shortwave propagation.

    "The current trend is expected to continue for the time being. A
    change will be caused by a decline in solar activity in the second
    decade of March. This will be very noticeable in the decline in
    solar radio flux."

    The greater than 2 MeV electron flux at geosynchronous orbit is
    expected to reach high levels on March 8, 11 and 12, and March 15 to
    19 due to anticipated influence from 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 range from quiet to G2
    (Moderate) geomagnetic storm levels. Active conditions are likely on
    March 10, 12, March 14 and 15, and March 20.ÿ Unsettled conditions
    are likely on March 8 and 9, March 11, March 13, and March 16 to 19.
    All elevated levels of geomagnetic activity are associated with the
    anticipated influence of multiple, recurrent, CH HSSs. The remainder
    of the outlook period is likely to be at mostly quiet levels.

    The current solar report from Dr. Tamitha Skov, WX6SWW, can be found
    on YouTube at, https://www.youtube.com/watch?v=6SoYfTnrudc[2] .

    The Predicted Planetary A Index for March 7 to 13 is 5, 8, 10, 18,
    10, 15, and 10, with a mean of 10.9.ÿ Predicted Planetary K Index is
    2, 3, 3, 4, 3, 4, and 3, with a mean of 3.1.ÿ 10.7-centimeter flux
    is 156, 156, 150, 145, 140, 135, and 128, with a mean of 144.3.

    For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[3] and the ARRL Technical Information
    Service web page at, http://arrl.org/propagation-of-rf-signals[4]. For
    an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[5] . Information and
    tutorials on propagation can be found at, http://k9la.us/[6] .

    Also, check this:

    https://bit.ly/3Rc8Njt[7]

    "Understanding Solar Indices" from September 2002 QST.

    ÿ


    [1] https://www.swpc.noaa.gov/phenomena/sunspotssolar-cycle
    [2] https://www.youtube.com/watch?v=6SoYfTnrudc
    [3] http://www.arrl.org/propagation
    [4] http://arrl.org/propagation-of-rf-signals
    [5] http://arrl.org/the-sun-the-earth-the-ionosphere
    [6] http://k9la.us/
    [7] https://bit.ly/3Rc8Njt
    ---
    þ Synchronet þ Whiskey Lover's Amateur Radio BBS
  • From ARRL de WD1CKS@VERT/WLARB to QST on Friday, March 13, 2026 20:29:15
    03/13/2026

    Solar activity was very low to low. Only low-level C-class activity
    was observed from Regions 4384 and 4389. Slight growth was observed
    in Regions 4384 and 4391. New Region 4392 was numbered. The rest of
    the spot groups were either stable or in decay. No Earth-directed
    CMEs were observed. Solar activity is expected to be at low levels,
    with a slight chance for M-class (R1-R2/minor-moderate) flares,
    through March 14.
    ÿ
    Solar wind parameters were enhanced through March 11. Solar wind
    speed ranged from approximately 480 to 570 km/s during this time but
    decreased to around 400-460 km/s through the rest of the period.
    ÿ
    High Speed Stream activity persists through March 14.

    Elevated probabilities are related to the flare potential of both
    currently observed spot groups as well as the potential from
    returning regions.

    No proton events are expected at geosynchronous orbit.

    The greater than 2 MeV electron flux at geosynchronous orbit is
    expected to be at high levels March 16 to 19, and then on March 23
    to 30 due to the influence from multiple, recurrent, Coronal Hole
    High Speed Streams. The remainder of the outlook period is likely to
    be at normal to moderate levels.

    Geomagnetic field activity is expected to reach G1 (Minor)
    geomagnetic storm levels on March 14, 22, and 25 during the onset of
    a CH HSS. G2 (Moderate) geomagnetic storm levels are likely on March
    21 due to negative polarity CH HSS effects. Unsettled to active
    levels are likely on March 15 to 20, 23 and 24, and on March 256 to
    28. All elevated levels of geomagnetic activity are associated with
    the anticipated influence of multiple, recurrent, CH HSSs. The
    remainder of the outlook period is likely to be at mostly quiet
    levels.

    The latest solar report from Dr. Tamitha Skov, WX6SWW, can be found
    on YouTube at, https://www.youtube.com/watch?v=c9gloRUmKAI[1] .

    The Predicted Planetary A Index for March 14 to 20 is 20, 15, 10,
    10, 10, 12, and 15, with a mean of 13.1.ÿ The Predicted Planetary K
    Index is 5, 4, 3, 3, 3, 4, and 4, with a mean of 4.1.ÿ 10.7
    centimeter flux is 110, 110, 110, 110, 110, 105, and 110, with a
    mean of 109.3.

    For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[2] and the ARRL Technical Information
    Service web page at, http://arrl.org/propagation-of-rf-signals[3]. For
    an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[4] . Information and
    tutorials on propagation can be found at, http://k9la.us/[5] .

    Also, check this:

    https://bit.ly/3Rc8Njt[6]

    "Understanding Solar Indices" from September 2002 QST.
    NNNN

    ÿ


    [1] https://www.youtube.com/watch?v=c9gloRUmKAI
    [2] http://www.arrl.org/propagation
    [3] http://arrl.org/propagation-of-rf-signals
    [4] http://arrl.org/the-sun-the-earth-the-ionosphere
    [5] http://k9la.us/
    [6] https://bit.ly/3Rc8Njt
    ---
    þ Synchronet þ Whiskey Lover's Amateur Radio BBS
  • From ARRL de WD1CKS@VERT/WLARB to QST on Friday, April 03, 2026 22:13:44
    04/03/2026

    Solar activity has been at low levels with only C-class flares
    produced by Regions 4401, 4405, and 4409. There were 9 numbered
    active regions on the solar disk, with 4409 showing the most
    significant growth during the period and producing the largest flares
    on April 1. A new region emerged but it has not yet been numbered.
    ÿ
    Multiple filaments erupted during the day on April 1, producing
    coronal mass ejections (CMEs) observed in coronagraph imagery, but
    their propagation modeling did not suggest impacts to Earth. The
    exceptions are the ejecta first observed at GONG H-alpha images on
    April 1.
    ÿ
    Solar activity is likely to reach moderate (R1/R2-minor/moderate)
    levels, with a slight chance for X-class (R3-strong) flares through
    April 4, due primarily to the flare potential of Regions 4404, 4405
    and 4409.
    ÿ
    Solar wind parameters were near nominal levels with solar wind speed
    averaging around 440 km/s.

    Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
    Ionosphere,ÿ April 2, 2026, by F. K. Janda, OK1HH:

    The increase in overall solar activity during the third ten-day
    period of March-albeit with a slight delay-led to a gradual rise in
    MUF values, extending into the first days of April. An increase in
    solar flare activity did not occur until April 30, beginning with a
    flare at 0319 UT with an X-ray intensity of X1.4, which lasted a long
    time and was accompanied by a CME. Since a large coronal hole No. 36
    was located nearby, a significant increase in geomagnetic activity
    was expected. This did not occur until April 2, but already during
    several preceding active intervals, we could observe the effects of electromagnetic wave scattering on ionospheric inhomogeneities,
    clearly visible even on ionograms.

    Active region NOAA 4405, located 27 degrees south of the solar
    equator, has been clearly visible for a week as the largest on the
    solar disk and appears to be stable. On April 3, it passes the
    central meridian, and its proximity to coronal hole No. 36 is a
    potential source of intensified solar wind. It also indicates higher geomagnetic activity (at G2 level since April 2). This proximity will
    likely be the cause of increased geomagnetic activity during the
    first ten days of April. Consequently, this will lead to irregular
    shortwave propagation conditions and more frequent drops in the MUF.

    The next increase in solar activity will likely occur in the last
    third of April. Daily MUF values will rise again, and at the same
    time, a sporadic E layer will begin to appear occasionally in
    mid-latitudes. Although it will not yet have a significant impact on
    shortwave propagation, it will occasionally cause interesting DX
    openings on the shortest shortwave bands.

    The Predicted Planetary A Index for April 4 to April 10 is 22, 10,
    15, 8, 7, 25, and 40 with a mean of 18.1. The Predicted Planetary K
    Index is 5, 3, 4, 3, 2, 5, and 6 with a mean of 4. 145, 145, 135,
    125, 118, 120, and 110 with a mean of 128.2

    For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[1]ÿand the ARRL Technical Information
    Service web page at,ÿhttp://arrl.org/propagation-of-rf-signals[2]. For
    an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[3]ÿ. Information and
    tutorials on propagation can be found at,ÿhttp://k9la.us/[4]ÿ.

    Also, check this:

    https://bit.ly/3Rc8Njt[5]

    "Understanding Solar Indices" from September 2002ÿQST.


    [1] http://www.arrl.org/propagation
    [2] http://arrl.org/propagation-of-rf-signals
    [3] http://arrl.org/the-sun-the-earth-the-ionosphere
    [4] http://k9la.us/
    [5] https://bit.ly/3Rc8Njt
    ---
    þ Synchronet þ Whiskey Lover's Amateur Radio BBS
  • From ARRL de WD1CKS@VERT/WLARB to QST on Friday, April 10, 2026 23:31:33
    04/10/2026

    Solar activity remained at low levels this week. Most of the C-class activity came from either Region 4414 or Region 4409, which has developed a delta spot in its intermediary area. All remaining spots were either stable or in slight decay, with Region 4406 rotating over the west limb by the end of the reporting period.
    ÿ
    Coronal activity was observed in CCOR-1, LASCO and STEREO available imagery during the period. Of the four eruptions, one was far-sided, one was too narrow plus too far north of the ecliptic to have any Earth-directed component, and two had the potential for Earth-directed components. The first was associated with a C2.4 flare from Region 4414 while there was no clear source for the second. Modeling indicates these eruptions will pass behind Earth's orbit and no impact is anticipated. Eruptions potentially associated with the C8.9 are currently being analyzed. Radio blackouts reaching the R1 levels were observed over the past 24 hours. The largest was on Apr 9th 2026 at 08:45 UTC.
    ÿ
    Solar activity is expected to be at low levels over April 9 to 11, with a chance for M-class (R1-R2/minor-moderate) flares and a slight chance for X-class (R3/strong or greater) flares, driven primarily by the flare potential of Regions 4409 and 4414. The greatest expected 3 hr Kp for Apr 09 through Apr 11 2026 is 5 (.33NOAA scale G1).

    A brief description of Sunspots can be found on the Space Weather
    Prediction Center website at, https://www.swpc.noaa.gov/phenomena/sunspotssolar-cycle[1]ÿ.
    ÿ
    Solar wind parameters reflected the transition out of a waning negative polarity coronal hole high speed stream (CH HSS) into nominal conditions. Wind speeds continued to decline from a peak of ~500 km/s to near 400 km/s by the end of the period.

    Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, April 9, 2026, by F. K. Janda, OK1HH:

    Perhaps the biggest surprise in recent days was that, following the geomagnetic disturbance of April 2-3 (which had been expected, albeit a day earlier and with lower intensity), there were no further major surprises. Solar activity declined as predicted, whereas because it declined over a relatively long period, there was a greater-than-expected drop in critical frequencies in the F2 ionospheric region at mid-latitudes.

    For forecasting developments in the second third of April, the 27-day cycle could serve as a relatively reliable guide this time. First of all, one might expect a one- to two-day increase in geomagnetic activity (which is also indicated by the presence of solar coronal holes near the central meridian), followed by relative calm. This is despite the short time that has elapsed since the eleven-year peak of solar activity.

    The Predicted Planetary A Index for April 4 to April 10 is 5, 4, 3, 2, 2, 2, and 2 with a mean of 2.8. The Predicted Planetary K Index is 18, 10, 8, 7, 5, 4, and 7 with a mean of 8.4. 10.7 centimeter flux is 106, 105, 108, 110, 115, 115, and 120 with a mean of 111.2.

    For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[2]ÿand the ARRL Technical Information
    Service web page at,ÿhttp://arrl.org/propagation-of-rf-signals[3]. For
    an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[4]ÿ. Information and
    tutorials on propagation can be found at,ÿhttp://k9la.us/[5]ÿ.

    Also, check this:

    https://bit.ly/3Rc8Njt[6]

    "Understanding Solar Indices" from September 2002ÿQST.


    [1] https://www.swpc.noaa.gov/phenomena/sunspotssolar-cycle
    [2] http://www.arrl.org/propagation
    [3] http://arrl.org/propagation-of-rf-signals
    [4] http://arrl.org/the-sun-the-earth-the-ionosphere
    [5] http://k9la.us/
    [6] https://bit.ly/3Rc8Njt
    ---
    þ Synchronet þ Whiskey Lover's Amateur Radio BBS
  • From Luis Silva@VERT/MSMACBBS to ARRL de WD1CKS on Thursday, April 16, 2026 19:20:55
    Test reply via API

    ---
    ï¿­ Synchronet ï¿­ MSmac BBS - msmacbbs.maletazul.pt
  • From ARRL de WD1CKS@VERT/WLARB to QST on Friday, April 17, 2026 21:48:14
    04/17/2026

    Solar activity was at very low levels with only isolated B-class
    flaring, mostly from Region 4416.
    ÿ
    There are currently four numbered regions on the visible disk. Region
    4416 remains the largest group by area but exhibited signs of
    structural weakening, including flux submergence and a slight decay
    of its intermediary pores. Region 4419 was the most complex group on
    the disk and showed flux emergence, growth, and divergence within its intermediary spots, leading to the development of a mixed-polarity
    gamma configuration. Region 4418 is trending toward plage with only
    two small bipolar pores remaining and Region 4415 remained stable.
    CMEs observed in coronagraph imagery were determined to be directed
    away from Earth.
    ÿ
    Solar wind parameters reflected waning coronal hole high speed stream influences toward a nominal regime. Solar wind speeds underwent a
    gradual, albeit erratic, decline from early-period highs near 420
    km/s, to stabilize around 375 km/s by the end of the reporting
    period. The phi angle was predominantly oriented in a positive (away
    from the Sun) direction.
    ÿ
    Solar wind parameters are expected to remain primarily near nominal
    levels through April 16. Significant enhancements are anticipated on
    April 17 with the onset of a co-rotating interaction region (CIR)
    that will precede the arrival of a negative polarity high-speed
    stream (-CH HSS).
    ÿ
    Spaceweather.com[1] reports a large hole has opened in the sun's
    atmosphere, and it is directly facing Earth. High-speed solar wind
    flowing from this coronal hole should arrive on April 18th,
    potentially sparking G2-class geomagnetc storms.

    Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
    Ionosphere, April 16, 2026, by F. K. Janda, OK1HH:

    It is as if we were not just past the 11-year solar activity maximum;
    the solar flux fell and remained below 100 s,f,u for five days (April
    9-13), while the number of sunspot groups dropped to just three.
    Flare activity declined similarly. However, more significant for the
    future development of solar activity-and especially for its impact on
    Earth-is the large coronal hole No. 42, which is approaching the
    central meridian from the northeast. Its western borderÿ can be
    considered a potential source of solar wind that will reach Earth in
    the coming days.

    Initially, it seemed that this would not happen until April 19, but
    closer observation of its development shows that the Earth will be
    hit by a fast solar wind as early as April 18 during the day. Or
    perhaps as early as the late afternoon of April 17, in which case the disturbance could begin with a positive phase (with an increase in
    MUF) while shouldÿ continue through the negative phase for much of
    the weekend.

    The latest solar report from Dr. Tamitha Skov, WX6SWW, can be found
    on YouTube.
    https://www.youtube.com/watch?v=cOcV9xp8qU8&pp=0gcJCdMKAYcqIYzv[2]

    The Predicted Planetary A Index for April 18 to April 24 is 15, 20,
    12, 10, 8, 5, and 8 with a mean of 11.1. The Predicted Planetary K
    Index is 3, 4, 4, 3, 3, 2, and 3 with a mean of 3.1. 10.7 centimeter
    flux is 110, 110, 120, 130, 140, 145, and 145 with a mean of 128.5.
    For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[3]ÿand the ARRL Technical Information
    Service web page at,ÿhttp://arrl.org/propagation-of-rf-signals[4]. For
    an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[5]ÿ. Information and
    tutorials on propagation can be found at,ÿhttp://k9la.us/[6]ÿ.

    Also, check this:

    https://bit.ly/3Rc8Njt[7]

    "Understanding Solar Indices" from September 2002ÿQST.


    [1] http://spaceweather.com
    [2] https://www.youtube.com/watch?v=cOcV9xp8qU8&pp=0gcJCdMKAYcqIYzv
    [3] http://www.arrl.org/propagation
    [4] http://arrl.org/propagation-of-rf-signals
    [5] http://arrl.org/the-sun-the-earth-the-ionosphere
    [6] http://k9la.us/
    [7] https://bit.ly/3Rc8Njt
    ---
    þ Synchronet þ Whiskey Lover's Amateur Radio BBS
  • From ARRL de WD1CKS@VERT/WLARB to QST on Friday, April 24, 2026 22:08:34
    04/24/2026

    Solar activity remained at low levels this past week with numerous C1
    flares from Region 4420, which exhibited growth during the period.
    Region 4419 showed minor decay, particularly in its trailing spots,
    while producing a lone C1.0 flare. Region 4422 was numbered during
    the period but remained inactive. No Earth-directed CMEs were
    observed in coronagraph imagery.

    Solar activity is expected to continue at low levels, with a slight
    chance for isolated M-class activity, through April 24, primarily due
    to the flare potential from Region 4420 and limb activity.

    Solar wind parameters reflected waning coronal hole high speed stream
    (CH HSS) influences. The wind speed maintained an average of 525
    km/s, and Phi was predominantly in a negative orientation towards the
    Sun.

    Region 4419ÿ was the most active region of the period, responsible
    for 5 out of the 7 C-class flares observed during the week, including
    the largest one: a C4.1. The remainder 2 C-class flares of the period
    were a C1.1 from Region 4414 and a C1.6 from Region 4416. Coronal
    activity was observed during the week with some filament eruptions
    and few CMEs without Earth-directed components.

    Spaceweather.com[1] reports the sun has been quiet for weeks. That ended
    today with two powerful X-class solar flares. In quick succession,
    sunspot 4419 unleashed X2.4 (0107 UT) and X2.5 (0813 UT) explosions.

    Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
    Ionosphere, April 23, 2026, by F. K. Janda, OK1HH:

    Although solar activity during the first four months of this year was
    lower than in the previous two years of the 11-year solar maximum
    (2024-2025), this was anything but a continuing decline. Periods of
    low solar activity gradually tended to lengthen and were interspersed
    with sudden increases in both overall and eruptive activity. This
    trend is very clearly evident in the solar flux, which was very low
    during the penultimate solar cycle (March 14-21), followed by a
    further and longer decline shortly after the beginning of April and particularly between April 9 and 13.

    Moreover, during the long period of low solar activity (April 5-22), geomagnetic field activity increased (April 18-21), further
    diminishing hopes for the usual seasonal improvement in shortwave
    propagation conditions. However, two sunspot groups then emerged on
    the eastern limb of the solar disk, bringing their total number to
    four. Then came Thursday, April 23, with several moderately powerful
    solar flares, alternating between the east and west of the solar
    disk, preceded by rapid changes in magnetic configuration where the
    eruptions were soon observed.

    Therefore, in the coming days we will continue to observe increased
    solar activity and the potential effects of fast solar wind on Earth.
    Shortwave propagation conditions will vary irregularly, while during
    the ongoing bursts of intense solar wind, ionospheric attenuation
    will increase at higher latitudes.

    The Predicted Planetary A Index for April 25 to May 1 is 8, 5, 5, 5,
    20, 18, and 12 with a mean of 10.4. The Predicted Planetary K Index
    is 3, 2, 2, 2, 5, 5, and 4 with a mean of 3.3. 10.7 centimeter flux
    is 115, 120, 125, 125, 125, 125, and 125 with a mean of 122.9.

    For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[2]ÿand the ARRL Technical Information
    Service web page at,ÿhttp://arrl.org/propagation-of-rf-signals[3]. For
    an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[4]ÿ. Information and
    tutorials on propagation can be found at,ÿhttp://k9la.us/[5]ÿ.

    Also, check this:

    https://bit.ly/3Rc8Njt[6]

    "Understanding Solar Indices" from September 2002ÿQST.


    [1] http://spaceweather.com/
    [2] http://www.arrl.org/propagation
    [3] http://arrl.org/propagation-of-rf-signals
    [4] http://arrl.org/the-sun-the-earth-the-ionosphere
    [5] http://k9la.us/
    [6] https://bit.ly/3Rc8Njt
    ---
    þ Synchronet þ Whiskey Lover's Amateur Radio BBS