SB PROP @ ARL $ARLP033 ARLP033 Propagation de K7RA ZCZC AP33 QST de W1AW Propagation Forecast Bulletin 33 ARLP033 From Tad Cook, K7RA Seattle, WA August 30, 2024 To all radio amateurs SB PROP ARL ARLP033 ARLP033 Propagation de K7RA "ASWFC GEOMAGNETIC DISTURBANCE WARNING ISSUED AT 0200 UTC/29 AUGUST 2024 BY THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE. The solar wind environment remains elevated due to ongoing CME effects. G0-G1 geomagnetic conditions are expected on 29-Aug. INCREASED GEOMAGNETIC ACTIVITY EXPECTED DUE TO CORONAL MASS EJECTION FOR 29 AUGUST 2024 GEOMAGNETIC ACTIVITY FORECAST 29 Aug: G0-G1." This week seven new sunspot groups emerged, with two on August 22, one on August 25, two on August 26 and two more on August 28. Average daily sunspot number declined slightly from 180.3 to 177.1, and average daily solar flux from 232.7 to 229. Planetary and middle latitude A index averages were about the same, at 12.3 and 12. Predicted solar flux shows 210, 220 and 215 on August 30 to September 1, 220 on September 2-3, 225 and 230 on September 4-5, 275 on September 6-8, 280, 285, 280 and 280 on September 9-12, then 275, 270, 265, 260, 255, 250, and 245 on September 13-19, then 240 on September 20-21, then 235, 230, 235, 240 and 245 on September 22-26, 250 on September 27-28, then 255, 260, 265 and 270 on September 29 through October 2, and 275 on October 3-5. Predicted planetary A index is 8 on August 30 to September 1, 5 on September 2-16, then 8, 8 and 12 on September 17-19, then 5 on September 20 to mid-October. Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere for August 29, 2024 from OK1HH. "About 10 sunspot groups can still be observed in the solar disk, two to four of which have magnetic field configurations that are indicative of middle magnitude flares. After several solar flares in recent days, the arrival of CMEs to Earth was widely expected. This was also true for the X1.1/2b class flare in AR 3784 (N12E05) with a maximum on August 14 at 0640 UT, accompanied by bursts of solar radio noise types II/IV. However, nothing special continued to happen either. So much so that some authors canceled the predictions of a geomagnetic disturbance on 27 August. Which was a mistake - the disturbance began on the afternoon of August 27, while reaching G2 level. For the state of the Earth's ionosphere, this happened at the right time. In the positive phase of the disturbance, the highest usable frequencies of the F2 layer increased, while propagation from Europe to the west coast of the USA through the ionospheric waveguides was observed up to around the boundary between HF and VHF. As expected, on 28 August the evolution in the negative phase of the disturbance continued with a significant decrease in f0F2, including an increase in attenuation. Surprisingly rapid improvement already occurred on the following day, August 29, while can be attributed not only to the high solar radiation in the ongoing solar cycle maximum, but also to the change in the polarity of the interplanetary magnetic field." Check Tamitha Skov's latest videos: https://www.youtube.com/user/SpWxfx Send your tips, reports, observations, questions and comments to k7ra@arrl.net. When reporting observations, don't forget to tell us which mode you were operating. For more information concerning shortwave radio propagation, see www.arrl.org/propagation and the ARRL Technical Information Service 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-archive-propagation. 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 at www.arrl.org/bulletins. Sunspot numbers for August 22 through 28 2024 were 175, 180, 172, 178, 202, 170, and 163, with a mean of 177.1. 10.7 cm flux was 230.6, 241.7, 232.6, 232.6, 232, 221.3, and 211.9, with a mean of 229. Estimated planetary A indices were 10, 7, 10, 7, 5, 11, and 26, with a mean of 12.3. Middle latitude A Index was 11, 8, 12, 8, 4, 11, and 30, with a mean of 12. NNNN /EX |
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