Subj : The K7RA Solar Update
To   : QST
From : ARRL de WD1CKS
Date : Wed Jul 24 2024 01:22 pm

07/19/2024

Big increase in solar activity this week, with average daily sunspot number
rising from 129 to 215.9, and solar flux from 176.6 to 226.5.

Fourteen new sunspot groups emerged. Two were on July 11, one on July 12, three
on July 13, one on July 14, two more on July 15, three more on July 16 and two
more on July 17.

On Thursday (after the reporting week) the daily sunspot number was 276, the
highest value for cycle 25, according to Jon Jones, N0JK. A new sunspot group
appeared that day.

Average planetary A index was quiet at 6, and the middle latitude number was 8.

More quiet geomagnetic indicators are forecast for the entire month of August,
with planetary A index predicted at 5 on every day.

Predicted solar flux is 210 on July 19-21, 200 on July 22-25, 180 on July
26-27, 175 on July 28, 170 on July 29-31, 165 on August 1-2, then 170, 180 and
190 on August 3-5, 200 on August 6-11, and 230 on August 12-14, then 210 on
August 15, 200 on August 16-18, then 195 and 185 on August 19-20, and 180 on
August 21-23.

Predicted planetary A index is 8, 16, 20 and 8 on July 19-22, and 5 on July 23
through the entire month of August and possibly the first week in September.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere for
July 18, 2024.

Increased solar flare activity continues. M-class eruptions are almost the
order of the day and X-class eruptions are no exception. Their main source is
currently the largest AR3751. While it is still in the southeast quadrant of
the solar disk, it will cross the central meridian as early as July 19. After
that the probability of an Earth impact by a possible CME will increase. In the
southwest quadrant we observe five sunspot groups: AR 3742, AR3743, AR3745,
AR3747 and AR3758, which were formed by the spill of the original extremely
active May AR3664 (designated as AR3697, AR3723 in subsequent solar rotations).

Solar activity remains high and geomagnetic disturbances are less frequent and
do not last long. Ionospheric shortwave propagation conditions, although mostly
slightly above average level, vary irregularly. The sporadic layer E will
continue for a few more weeks. We will continue to see fading during the day,
in particular at lower shortwave frequencies (on the 7 MHz band and much more
often and longer on 3.5 MHz) during moderate flares. Entire shortwave bursts
will die down here and there during the largest flares, especially long-lasting
X-class flares.� F. K. Janda, OK1HH

Video from Tamitha Skov: https://youtu.be/GLBIY3bbdQE[1]

Solar Flare: https://bit.ly/3Wp9wjA[2]

Martian aurora: https://bit.ly/4cJ2L21[3]

Blackouts: https://bit.ly/468L89c[4] ��https://bit.ly/3LrTxex[5]

https://bit.ly/3Lx0ye6[6] ��https://bit.ly/3Y7Lgnq[7]

Cycle 26: https://bit.ly/3YaG02h[8]

Send your tips, reports, observations, questions and comments to
[email protected][9] . When reporting observations, don't forget to tell us which
mode you were operating.

For more information concerning shortwave radio propagation, see
http://www.arrl.org/propagation[10] and the ARRL Technical Information Service
web page at, http://arrl.org/propagation-of-rf-signals[11].

For an explanation of numbers used in this bulletin, see
http://arrl.org/the-sun-the-earth-the-ionosphere[12] .

An archive of past propagation bulletins is at
http://arrl.org/w1aw-bulletins-archive-propagation[13] . �

More good information and tutorials on propagation are at http://k9la.us/[14] �

Also, check this: https://bit.ly/3Rc8Njt[15] �

Instructions for starting or ending email distribution of ARRL bulletins are at
http://arrl.org/bulletins[16] .

Sunspot numbers for July 11 through 17 2024 were 188, 162, 214, 217, 205, 250,
and 275, with a mean of 215.9. 10.7 cm flux was 205, 209.7, 238.3, 233.9,
233.2, 241.9, and 223.8, with a mean of 226.5. Estimated planetary A indices
were 6, 5, 4, 5, 7, 10, and 5, with a mean of 6. Middle latitude A Index was 7,
7, 6, 9, 8, 12, and 7, with a mean of 8.

�


[1] https://youtu.be/GLBIY3bbdQE
[2] https://bit.ly/3Wp9wjA
[3] https://bit.ly/4cJ2L21
[4] https://bit.ly/468L89c
[5] https://bit.ly/3LrTxex
[6] https://bit.ly/3Lx0ye6
[7] https://bit.ly/3Y7Lgnq
[8] https://bit.ly/3YaG02h
[9] mailto:[email protected]
[10] http://www.arrl.org/propagation
[11] http://arrl.org/propagation-of-rf-signals
[12] http://arrl.org/the-sun-the-earth-the-ionosphere
[13] http://arrl.org/w1aw-bulletins-archive-propagation
[14] http://k9la.us/
[15] https://bit.ly/3Rc8Njt
[16] http://arrl.org/bulletins

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� Synchronet � Whiskey Lover's Amateur Radio BBS

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