= NOW 18 WPM transition file follows =

Solar activity was quiet over the past week, but geomagnetic numbers
were way, way up.  Average daily sunspot numbers dropped from 178.4
to 120, and average daily solar flux from 223.7 to 175.7.  Average
daily planetary A index rocketed from 7.9 to 35.7, and middle
latitude numbers from 11.1 to 23.4.  Six new sunspot groups emerged
over the past week, one each on September 13 and 14, two on
September 16, and two each on September 17 and 18.  Predicted solar
flux is 160 and 155 on September 20 and 21, 150 on September 22 to
26, then a huge leap to 230 and 225 on September 27 and 28, 240 on
September 29 through October 2, 230 on October 3, 220 on October 4
and 5, then 215, 205 and 207 on October 6 to 8, 201, 186 and 172 on
October 9 to 11, 173 and 175 on October 12 and 13, 170 on October 14
to 16, 165 on October 17 and 18, 170 on October 19, 225 on October
20 and 21, then 230, 225, 230 and 225 on October 22 to 25, then 240
on October 26 to 29.  Predicted planetary A index is 5, 10 and 8 on
September 20 to 22, 5 on September 23 to 26, then 25, 15 and 10 on
September 27 to 29, then 5 on September 30 through October 4, 10 on
October 5 and 6, and 5 on October 7 to 9, 10 on October 10, 20 on
October 11 to 13, 15 on October 14, 10 on October 15 and 16, then 5
on October 17 to 22, 25 on October 23 and 24, and 15 and 10 on
October 25 and 26.  Weekly Commentary on the Sun, the Magnetosphere,
and the Earths Ionosphere, September 19, 2024 from F.K. Janda,
OK1HH, Overall solar activity has decreased slightly in recent days,
but before that AR3825 produced energetic flares, including two of
the largest, X1.3 on September 12th and a very strong X4.5 on
September 14th.  The arrival of the CMEs and the onset of the
disturbance, expected on the afternoon of UT Sept 16th, was delayed
and registered as an influx of protons in the solar wind at 2244 UT
Sept 16th. After that, a geomagnetic disturbance started to develop,
which significantly affected the shortwave propagation conditions,
especially on 17 September.  A more pronounced upsurge in solar flux
can be expected once the large active regions known to be present
through helioseismology start to reappear at the eastern limb of the
solar disk.  This should happen around 26 September. However, a
repeat of the August 28 and 29 disturbance is expected in the same
period.  Therefore, an improvement in propagation conditions can be
expected before September 26, or better yet, shortly during the
onset of the disturbance after which a deterioration will occur.
Links to articles from Dr. Tamitha Skov, sunspots, ARRL
informational pages, STCE newsletter, solar indices, and solar
information can be found in teleprinter, packet, and Internet
versions of 2024 Propagation Forecast Bulletin ARLP036.  Sunspot
numbers were 160, 127, 136, 68, 103, 140, and 106, with a mean of
120. 10.7 cm flux was 201.2, 185.8, 172.4, 172.8, 169.2, 165.4, and
163.3, with a mean of 175.7.  Estimated planetary A indices were 67,
37, 21, 19, 23, 71, and 12, with a mean of 35.7. Middle latitude A
Index was 36, 22, 22, 16, 19, 39, and 10, with a mean of 23.4.

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