ZCZC AP47
QST de W1AW
Propagation Forecast Bulletin 47 ARLP047
From Tad Cook, K7RA
Seattle, WA December 6, 2024
To all radio amateurs
SB PROP ARL ARLP047
ARLP047 Propagation de K7RA
Solar activity seems to have dropped dramatically from a recent peak. Are we ov ly to say.
Daily average sunspot numbers this week sank to 120.1.
Predicted solar flux is 175 on December 6 to 8, 170 on December 9 and 10, 175 o 17.
Predicted planetary A index is 8 on December 6 and 7, 5 on December 8 to 12, 10
to 18, 12 and 8 on December 19 and 20 and 5 on December 21 through January 6,
Commentary from OK1HH:
"After the unexpected solar proton flare of 21 November, which took place beyon y protons hit the Earth's atmosphere. This solar radiation storm had a greater phere, where it caused a significant increase in attenuation.
"Two days later, two new large sunspot groups appeared near the southeastern li
daily, which is more or less normal for the 11-year maximum. These are AR3905 here they can be observed with the naked eye. There is a relatively small coron solar wind enhancement.
"Following the eruption of a plasma filament near AR3901, a G2 class geomagneti a CME is expected to impact. However, around 1900 UT on November 28, when this l happening. We will see what happens next. It is quite possible that the plasm is also not out of the question that it will miss the Earth completely. So any f coming true."
Send your tips, reports, observations, questions and comments to
k7ra@arrl.net. ll us which mode you were operating.
For more information concerning shortwave radio propagation, see www.arrl.org/p rvice web page at, www.arrl.org/propagation-of-rf-signals.
For an explanation of numbers used in this bulletin, see www.arrl.org/the-sun-the-earth-the-ionosphere.
An archive of past propagation bulletins is at www.arrl.org/w1aw-bulletins-arch
More good information and tutorials on propagation are at
http://k9la.us.
Also, check "Understanding Solar Indices" from September 2002 QST:
https://bit.ly/3Rc8Njt.
Instructions for starting or ending email subscriptions to ARRL bulletins are a
Sunspot numbers for November 28 through December 4, 2024 were 149, 162, 103, 83 cm flux was 213.9, 219.8, 204, 186.3, 185.3, 174.2, and 174.7, with a mean of 2 1, 7, 6, 13, and 7, with a mean of 8.3. Middle latitude A Index was 3, 6, 9, 6, NNNN
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