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ARLP006 Propagation de K7RA

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Feb 9, 2024, 10:36:17 AMFeb 9
ARLP006 Propagation de K7RA

Propagation Forecast Bulletin 6 ARLP006
>From Tad Cook, K7RA
Seattle, WA February 9, 2024
To all radio amateurs

ARLP006 Propagation de K7RA

Over the recent reporting week, February 1-7, ten new sunspot groups
emerged, five on February 1, one on February 2, another on February
3, two on February 5, and one more on February 7. On February 8, two
more emerged.

Sunspot numbers and solar flux rose, and geomagnetic numbers were

Average daily sunspot number increased from 71.8 to 142.3, and
average daily solar flux from 145.4 to 165.5.

Geomagnetic conditions were quieter. Average daily planetary A index
decreased from 6.9 to 5.1, and average middle latitude numbers from
5.6 to 4.4.

Now let's see what the outlook might be over the next few weeks,
with data from the US Air Force and NOAA.

Predicted solar flux is 180 on February 9, then 175, 175, 180 and
175 on February 10-13, 178 on February 14-15, 170 on February 16,
160 on February 17-21, then 165 and 160 on February 22-23, 150 on
February 24-28, then 155, 160 and 165 on February 29 through March
2, 170 on March 3-5, 160 on March 6-9, 170 on March 10, 165 on March
11-13, 170 on March 14, and 160 on March 15-19.

Predicted planetary A index is 15, 12 and 8 on February 9-11, 5 on
February 12-25, then 8 and 7 on February 26-27, then 5 on February
28 through March 2, 10 on March 3-4, 5 on March 5-23.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere - February 8, 2024 from F.K. Janda, OK1HH:

"As recently as early January, it appeared that the peak of the
current eleven-year cycle would soon be passed, or perhaps even
passed late last year. But January's upsurge in solar activity led
us astray, and February, it seems, could be even more lively.

"Surprise number two is that although we are seeing moderate flares
on the Sun, some of which are proton flares and a few of which are
accompanied by CMEs, the solar wind around the Earth is intensifying

"Surprise number three, though related to the previous one, is the
decline in the Earth's magnetic field activity for more than a

"Finally, surprise number four is that although solar activity is
relatively high, while geomagnetic activity is low, the shortwave
propagation conditions (as defined at frequencies of 3-30 MHz) are
not nearly as good as we have become accustomed to during decades of
similar developments.

"Even from the proton solar flare with CME ejection observed on
February 6, we expect the Earth to be hit by an enhanced solar wind
with a subsequent, at least slight, rise in geomagnetic field
activity. This should occur between evening hours of UTC 9 February,
and the following morning. So, the question is slowly emerging
whether it will be more of a surprise if the disturbance starts or
if it doesn't."

Reader David Moore sent this article about slow moving solar flares:

Articles about the consequences of a modern Carrington Event:

Two stories about Radio Blackout:

Nice pictures of a Big Sunspot:

Our first Solar Maximum?

The latest report from Dr. Tamitha Skov, WX6SWW:

Solar news articles:

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

For more information concerning shortwave radio propagation, see and the ARRL Technical Information
Service web page at, . For
an explanation of numbers used in this bulletin, see .

An archive of past propagation bulletins is at . More good
information and tutorials on propagation are at .

Also, check this QST article about Solar Indices:

Instructions for starting or ending email distribution of ARRL
bulletins are at .

Sunspot numbers for February 1 through 7 2024 were 113, 131, 123,
138, 152, 175, and 164, with a mean of 142.3. 10.7 cm flux was
136.9, 142.6, 156.4, 170.4, 173.4, 190.3, and 188.4, with a mean of
165.5. Estimated planetary A indices were 5, 3, 3, 6, 7, 8, and 4,
with a mean of 5.1. Middle latitude A index was 4, 3, 2, 5, 6, 8,
and 3, with a mean of 4.4.

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