Via the ARRL: The K7RA Solar Update

“GEOMAGNETIC DISTURBANCE WARNING ISSUED AT 0132 UTC ON 15 DECEMBER 2023 BY THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE.

“Two predominately westward CMEs were observed on 14-Dec and
component arrivals are expected on 17-Dec.

“INCREASED GEOMAGNETIC ACTIVITY EXPECTED FOR 17 DECEMBER 2023.”

Spaceweather.com issued this alert on Thursday:

“MAJOR X-CLASS SOLAR FLARE: The Sun just unleashed the strongest
solar flare of Solar Cycle 25 (so far), an X2.8-class explosion from
unstable sunspot AR3514. The blast caused a deep shortwave radio
blackout over the Americas and may have hurled a fast CME toward
Earth.”

Solar activity declined this week. Average daily sunspot numbers
dropped from 121.1 to 110.3, and average daily solar flux from 146.5
to 129.8.

With such low geomagnetic activity, conditions were good for last
weekend’s ARRL 10 Meter Contest, although some wished for more
sunspots.

Six new sunspot groups appeared this week. The first two on December
8, another two on December 11 and 12, and two more on December 13.

Geomagnetic conditions were quieter, with planetary A index dropping
from 14.1 to 5.6, and middle latitude numbers from 7.3 to 4.6.

Predicted solar flux shows some expected improvement, with values
peaking at 160 on December 20-22, and 155 on January 23.

Predicted solar flux is 135 on December 15-16, then 145, 150 and 155
on December 17-19, 160 on December 20-22, but dropping back to 140
on December 23-24, 150 on December 25-26, then 155, 150 and 145 on
December 27-29, then 140 on December 30 through January 2, 2024, and
135 on January 3-5, then 130, 125, 120, 118, and 120 on January
6-10, 122 on January 11-12, then 124, 125, and 130 on January 13-15,
135 on January 16-18, 140 on January 19-20, and 150 on January
21-22.

Predicted planetary A index is 18 and 22 on December 15-16, 12 on
December 17-18, then 18, 8, 8, 20 and 10 on December 19-23, 5 on
December 24-29, 8 on December 30-31, then 10 and 8 on January 1-2,
2024, 5 on January 3-6, 12 on January 7-9, 8 and 5 on January 10-11,
12 on January 12-13, then 15, 25, 8, 5, 20 and 10 on January 14-19,
and 5 for at least the following few days.

“Weekly Commentary on the Sun, the Magnetosphere, and the Earth’s
Ionosphere December 15-21, 2023 from F.K. Janda, OK1HH:

“Solar activity has been gradually decreasing over the last seven
days, broadly in line with the forecast.

Read more – via American Radio Relay League | Ham Radio Association and Resources http://www.arrl.org/news/view/the-k7ra-solar-update-808