SB PROP @ ARL $ARLP022 ARLP022 Propagation de K7RA ZCZC AP22 QST de W1AW Propagation Forecast Bulletin 22 ARLP022 From Tad Cook, K7RA Seattle, WA June 14, 2024 To all radio amateurs SB PROP ARL ARLP022 ARLP022 Propagation de K7RA "ASWFC GEOMAGNETIC DISTURBANCE WARNING ISSUED AT 0650 UTC/14 JUNE 2024 BY THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE. "A weak halo CME may impact Earth either on late UTC day 15-Jun or else early UTC day 16-Jun. "INCREASED GEOMAGNETIC ACTIVITY EXPECTED DUE TO CORONAL MASS EJECTION FROM 15-16 JUNE 2024" Solar activity was lower over the past reporting week, June 6-12. Ten new sunspot groups emerged, two on June 6, one on June 7, two on June 9, and five on June 12. Average daily sunspot number dropped from 44 points from 183.4 to 139.4, and average daily solar flux from 184.8 to 179.2. Average daily planetary A index went from 8 to 11.6, and middle latitude numbers from 9.4 to 11.1. The most active day geomagnetically was June 7, when the planetary A index was 28. Alaska's College A index was 38. This was an unexpected G2 geomagnetic storm that commenced at 1130 UTC. Spaceweather.com reports a polar cap absorption event on June 12-13. Protons from the Sun are raining down on Earth, and it is causing shortwave blackouts. You can monitor it here: https://bit.ly/3Vpopko Predicted solar flux shows a peak at 205 on June 26-29 and again on July 23-26. The forecast shows flux at 170 on June 14, 175 on June 15-17, then 180 on June 18-20, then 185, 190 and 195 on June 21-23, 200 on June 24-25, 205 on June 26-29, then 200, 190, 180, 175, 170, 165, 160 and 175 on June 30 through July 7, then 170 on July 8-9, 165 on July 10-11, 155 on July 12-13, then 165 and 175 on July 14-15, 185 on July 16-18, then 190, 195 and 200 on July 19-21. Predicted planetary A index is 5, 12 and 15 on June 14-16, then 8 on June 17-18, then 5 on June 19-21, then 8 on Jun 22-23, then 5 on June 24-29, 8 on June 30 and July 1, and 5 on July 2-6, then 8 on July 7, 5 on July 8-15, then 8, 8, 5, 8 and 8 on July on July 16-20. "Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere - June 13, 2024, from OK1HH. "Despite the fact that the large sunspot group responsible for the geomagnetic disturbances and the beautiful auroras of May 10-11 is now on the far side of the Sun, its flares are showering the Earth's surroundings with a rain of protons. On the whole, however, there is no doubt that after its reappearance at the eastern edge of the solar disk, solar activity will again increase significantly, with solar flux values exceeding 200 in late June and early July. "For now, we will be content with the consequences of a slight decrease in overall solar activity, although moderate solar flares are no exception. Upswells in geomagnetic activity occur only occasionally and most days are quiet to unsettled. Summer prevails in the Earth's northern hemisphere, and sporadic-E layer events contribute even more than solar events to the erratic shortwave propagation conditions here. "With the exception of the two largest active regions, however, there is little going on at present on the far side of the Sun, and so July already seems to be considerably quieter than May and June were." Radiation risks for Mars astronauts: https://bit.ly/4b272M7 Viewing sunspots from Mars: https://go.nasa.gov/3RsTP87 May solar images from various online sources: https://bit.ly/45lmVvS https://bit.ly/3VFwCCb https://www.space.com/sun-solar-storm-may-10-timelapse https://bigthink.com/hard-science/sun-activity-2024/ Next weekend is ARRL Field Day, June 22-23. Solar flux and sunspot numbers should be rising at that time, and predicted planetary A index is a moderate 8. There will be an updated forecast in next week's bulletin. 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 http://www.arrl.org/propagation and the ARRL Technical Information Service web page at, http://arrl.org/propagation-of-rf-signals. For an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere. An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation. More good information and tutorials on propagation are at http://k9la.us/. Also, check this QST article about Solar Indices: https://bit.ly/3Rc8Njt Instructions for starting or ending email distribution of ARRL bulletins are at http://arrl.org/bulletins. Sunspot numbers for June 6 through 12 2024 were 149, 150, 143, 148, 146, 95, and 145, with a mean of 139.4. 10.7 cm flux was 190.9, 184.4, 190.4, 180.9, 177.8, 164.9, and 164.9, with a mean of 179.2. Estimated planetary A indices were 6, 28, 14, 5, 11, 12, and 5, with a mean of 11.6. Middle latitude A index was 7, 20, 15, 6, 11, 13, and 6, with a mean of 11.1. NNNN /EX | 
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