SB PROP @ ARL $ARLP021
ARLP021 Propagation de K7RA

ZCZC AP21
QST de W1AW 
Propagation Forecast Bulletin 21 ARLP021
From Tad Cook, K7RA
Seattle, WA May 26, 2023
To all radio amateurs 

SB PROP ARL ARLP021
ARLP021 Propagation de K7RA

Both average daily sunspot numbers and solar flux increased this
week. Average daily sunspot numbers rose from 118.6 to 133.4, while
average solar flux went from 143.2 to 161.2.

Geomagnetic indicators were more active. Average daily planetary A
index went from 9.6 to 17.1, while average middle latitude A index
rose from 9.6 to 14.4.

Predicted solar flux is 150 on May 26, 155 on May 27 and 28, then
150, 145, 140 and 135 on May 29 through June 1, 155 on June 2 to 4,
then 160, 165, 160, 155, and 150 on June 5 to 9, 145 on June 10 and
11, 150 on June 12, 155 on June 13 and 14, 160 on June 15, 165 on
June 16 and 17, then 160, 155 and 150 on June 18 to 20, 155 on June
21 and 22, then 160, 165 and 160 on June 23 to 25, 155 on June 26
and 27, 150 on June 28, and 155 on June 29 to July 1, then 160, 165
and 160 on July 2 to 4.

Predicted planetary A index is 15, 8, 5, 12 and 10 on May 26 to 30,
5 on May 31 through June 1, then 16, 8, 10 and 8 on June 2 to 5, 5
on June 6 to 15, then 12, 10, 5, 18, 22, 15 and 10 on June 16 to 22,
5 on June 23 to 28, then 16, 8, 10 and 8 on June 29 through July 2,
and 5 through the first week of July.

"Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere - May 25, 2023

We've seen another seven days of turbulent developments on the Sun
and around the Earth. The large, seen even without binoculars
(e.g., eclipse glasses) visible sunspot group AR3310 in the southern
hemisphere was the source of the strongest flare on May 16 with an
X-ray event maximum of M9.6.

Another group AR3311 in the north, due to its unstable magnetic
field configuration "beta-gamma-delta", produced almost all the
other flares. The stronger ones were the cause of Dellinger events
(SWF = Shortwave fadeout, in the case of M9.6 it was registered in
the whole shortwave range in the region where the Sun was high).
Moreover, the eruptions, combined with sporadic E layer, often
significantly affected the propagation in the lower shortwave bands
by deep and irregular fadeouts.

SOHO recorded a rare conjunction on May 21, when a filament near the
Sun's north pole was ejected as a CME in direction to the Pleiades,
Seven Sisters star cluster. Coronagraph on SOHO has been operating
since 1995 and was the first to operate in real time. No one had
ever seen anything like it before.

Since May 24, we observed a new and rapidly growing group of spots,
AR3315, in which we can expect more major solar flares as time goes
on. So the turbulent evolution with changing and often worsening
shortwave propagation conditions continues.