\n<\/p>\n
Solar activity seems to have dropped dramatically from a recent peak.\u00a0 <\/span>Are we over the cycle peak and headed down again?\u00a0 <\/span>Too early to say. <\/span><\/p>\n Daily average sunspot numbers this week sank to 120.1. <\/span><\/p>\n Predicted solar flux is 175 on December 6 to 8, 170 on December 9 and 10, 175 on December 11 and 12, and 205 on December 13 to 17. <\/span><\/p>\n Predicted planetary A index is 8 on December 6 and 7, 5 on December to 12, 10, 8 and 5 on December 13 to 15, 8 on December 16 to 18, 12 and 8 on December 19 and 20 and 5 on December 21 through January 6, 2025. <\/span><\/p>\n Commentary from OK1HH: <\/span><\/p>\n “After the unexpected solar proton flare of 21 November, which took place beyond the Sun’s western limb, a rain of higher-energy protons hit the Earth’s atmosphere.\u00a0 <\/span>This solar radiation storm had a greater impact at higher latitudes in the southern hemisphere, where it caused a significant increase in attenuation. <\/span><\/p>\n “Two days later, two new large sunspot groups appeared near the southeastern limb of the Sun.\u00a0 <\/span>These produced moderate eruptions daily, which is more or less normal for the 11-year maximum.\u00a0 <\/span>These are AR3905 and AR3906, which have grown rapidly to a size where they can be observed with the naked eye.\u00a0 <\/span>There is a relatively small coronal hole near them that could be influencing the solar wind enhancement. <\/span><\/p>\n “Following the eruption of a plasma filament near AR3901, a G2 class geomagnetic storm is possible on November 28 and 29, when a CME is expected to impact.\u00a0 <\/span>However, around 1900 UT on November 28, when this information is written as usual, nothing is still happening. We will see what happens next.\u00a0 <\/span>It is quite possible that the plasma cloud will only hit the Earth a little and it is also not out of the question that it will miss the Earth completely.\u00a0 <\/span>So any prediction at this point has a low probability of coming true.” <\/span><\/p>\n Send your tips, reports, observations, questions and comments to k7ra@arrl.net.\u00a0 <\/span>When reporting observations, don’t forget to tell us which mode you were operating. <\/span><\/p>\n For more information concerning shortwave radio propagation, see and the ARRL Technical Information Service web page at, . <\/span><\/p>\n For an explanation of numbers used in this bulletin, see<\/span><\/p>\n . <\/span><\/p>\n An archive of past propagation bulletins is at <\/span><\/p>\n http:\/\/arrl.org\/w1aw-bulletins-archive-propagation\u00a0 <\/span><\/span><\/p>\n More good information and tutorials are at <\/span><\/p>\n Also, check “Understanding Solar Indices” from September 2002 QST: .<\/span><\/p>\n I<\/span>nstructions for starting or ending email subscriptions to ARRL b<\/span>ulletins are at <\/span><\/span> .<\/p>\n \u00a0Sunspot numbers for November 28 through December 4, 2024 were 149, <\/span>162, 103, 83, 113, 126, and 105, with a mean of 120.1.\u00a0 <\/span>10.7 cm flux <\/span>was 213.9, 219.8, 204, 186.3, 185.3, 174.2, and 174.7, with a mean <\/span>of 202.2.\u00a0 <\/span>Estimated planetary A indices were 4, 8, 11, 7, 6, 13, <\/span>and 7, with a mean of 8.3.\u00a0 <\/span>Middle latitude A Index was 3, 6, 9, 6, <\/span>6, 6, 10, and 5, with a mean of 6. <\/span><\/p>\n<\/p><\/div>\n