= NOW 18 WPM transition file follows =

Ten new sunspot groups appeared over this reporting week, August 15
to 21, but both solar flux and sunspot numbers were lower, due to
the extraordinary numbers in the previous week.  Average daily
sunspot number declined from 255 to 180.3, while average daily solar
flux went from 284.9 to 232.7.  Geomagnetic numbers were quieter.
Average daily planetary A index declined from 28.6 to 11.9, and
average daily middle latitude numbers sank from 17.8 to 12.  On
August 17 the planetary A index was 31, caused by a CME around 1400
UTC.  A strong G3 geomagnetic storm was the result.  One new sunspot
group appeared on August 15, and two more emerged on every day from
August 16 to 19, and one more on August 21.  Predicted solar flux is
230 and 235 on August 23 and 24, then 240 on August 25 and 26, 230
on August 27, 235 on August 28 and 29, 205, 210 and 215 on August 30
through September 1, 220 on September 2 and 3, 225 on September 4 to
6, 220 on September 7, 225 on September 9, 230 on September 10 to
12, and 225 on September 13 to 16, 215 and 210 on September 17 and
18, 200 on September 19 and 20, then 205, 210, 205 and 200 on
September 21 to 24, and 205 on September 25 and 26.  The planetary A
index prediction shows 8 on August 23, and 5 on August 24 to
September 17, 18 and 12 on September 18 and 19, then 5 on September
20 through the first week in October.  I get mail asking why ten
meters isnt open during all of the recent high solar activity.  The
reason is the season.  We have to be much closer to the autumnal
equinox to see ten meters open regularly.  Weekly Commentary on the
Sun, the Magnetosphere, and the Earths Ionosphere for August 22,
2024 from OK1HH.  After the solar flare X1.1 on 14 August,
accompanied by a CME, we expected a geomagnetic storm.  A more
accurate prediction was provided by the NASA model, the disturbance
in agreement with it started on 17 August around 1400 UT.  The
geomagnetic storm was strong, G3, probably triggered by the arrival
of more than one CME.  We observe two to three sunspot groups on the
solar disk that can produce moderate flares, they have a betagamma
magnetic field.  There are usually 10 to 12 groups in total.
Coronal holes are few and relatively small, which reduces the
likelihood of an increase in solar wind speed.  Semi regularly, days
with higher MUF values, until Aug 17, Aug 19 and Aug 21, alternated
with decreases, Aug 14, Aug 18, Aug 20, which could only be
predicted to a very limited extent and only for shorter intervals
based on measured interplanetary magnetic field variations.  But
these are mostly impossible to predict.  Solar activity has remained
at a 20 year high for most of this summer, and so far there is no
indication of a possible decline.  Send your tips, reports,
observations, questions and comments to k7ra at arrl.net.  When
reporting observations, dont forget to tell us which mode you were
operating.  For more information concerning shortwave radio
propagation, see //www.arrl.org/propagation and the ARRL Technical
Information Service web page.  More information and tutorials on
propagation are at //k9la.us/ .  Instructions for starting or ending
email subscriptions to  ARRL bulletins are at arrl.org/bulletins .
Sunspot numbers for August 15 through 21 2024 were 164, 169, 170,
170, 213, 200, and 176, with a mean of 180.3.  10.7 cm flux was
227.4, 224.9, 229.5, 231, 239.1, 238.2, and 239, with a mean of
232.7.  Estimated planetary A indices were 6, 8, 31, 13, 10, 7, and
8, with a mean of 11.9.  Middle latitude A Index was 6, 11, 24, 15,
11, 9, and 8, with a mean of 12.

= END OF 18 WPM transition file <