TZUTC: -0500   
   MSGID: 192.fidonet-ls_arrl@1:2320/33 2711e0d4   
   PID: Synchronet 3.19c-Win32 master/5ab79049b Jun 14 2022 MSC 1929   
   TID: SBBSecho 3.15-Win32 master/5ab79049b Jun 14 2022 MSC 1929   
   BBSID: TBOLT   
   CHRS: ASCII 1   
   SB PROP @ ARL $ARLP024   
   ARLP024 Propagation de K7RA   
      
   ZCZC AP24   
   QST de W1AW    
   Propagation Forecast Bulletin 24  ARLP024   
   From Tad Cook, K7RA   
   Seattle, WA  June 17, 2022   
   To all radio amateurs   
      
   SB PROP ARL ARLP024   
   ARLP024 Propagation de K7RA   
      
   Solar activity increased this week, which we were happy to see, with   
   average daily sunspot number rising from 44.4 last week to 74.3   
   during this reporting week, June 9-15. Sunspot numbers rose all   
   week, starting at 17 on Thursday, June 9 to 149 on Wednesday, June   
   15.   
      
   Average daily 10.7 cm solar flux increased from 99.4 to 123.9. Solar   
   flux peaked at 145.5 on Tuesday, June 14, but then on Thursday the   
   noon daily reading at the Penticton observatory was 146.7, an   
   increase from 140 the day before. Also on Thursday, daily sunspot   
   number increased from 149 on Wednesday to 159.   
      
   The Penticton observatory does three daily readings of solar flux,   
   but it is the local noon reading that is the official solar flux   
   reading of the day, and the one we report here.   
      
   You can see the readings at https://bit.ly/3b5OBNk .   
      
   The solar flux outlook appears promising for the next few days. The   
   June 16, 2022 forecast from the USAF Space Weather Squadron shows   
   solar flux at 146 on June 17-18, then 144, 140, and 138 on June   
   19-21, 136 on June 22-24, 100 on June 25 through July 5, then 105,   
   110 and 115 on July 6-8, 120 on July 9-11, 125 on July 12-16, 120 on   
   July 17-18, 110 on July 19 and 100 on July 20-31.   
      
   Predicted planetary A index, a measure of geomagnetic stability, is   
   8 on June 17-18, 5 on June 19-24, then 10, and 8 on June 25-26, 5 on   
   June 27 through July 7, 8 on July 8-10, then 5, 8, 12, 10 and 8 on   
   July 11-15, then 5 on July 16-19, then 12, 18, 10 and 8 on July   
   20-23, and 5 through the end of the month.   
      
   You can find daily updates for predicted solar flux and A index at   
   https://services.swpc.noaa.gov/text/45-day-ap-forecast.txt . Updates   
   are posted every afternoon, North America time.   
      
   F.K. Janda, OK1HH wrote:   
      
   "Solar activity grew. The most significant phenomenon was observed   
   in the southeast quadrant of the solar disk - a long-duration (LDE)   
   M3/1n solar flare, observed at 0407 UTC on June 13, accompanied by   
   type-II and IV radio emissions and radio bursts.   
      
   "The associated CME was visible off the east. The arrival of the   
   ejected cloud of particles on Earth was calculated to the afternoon   
   of June 15.   
      
   "Interplanetary magnetic field strength increased at 0400 UTC on   
   June 15. Solar wind speed was about 500 km/s until shock arrival,   
   when it escalated to 550 km/s and eventually peaked at 624 km/s at   
   0556 UTC.  The geomagnetic field was quiet to active, with an   
   escalation to G1 (Minor) storm levels during the 1200-1500 UTC in   
   reaction to CME effects.   
      
   "The MUF increase caused by the storm was registered on June 15 at   
   two intervals, first after 0600 UTC and second before 1200 UTC. In   
   the afternoon to evening a decrease in MUF followed, an increase in   
   the decline and an overall worsening.   
      
   "Solar activity will remain elevated for several days, which will   
   help conditions return to above average levels. However, in the   
   Earth's northern hemisphere, sporadic-E layer will cause very   
   irregular development, from increased attenuation to more frequent   
   opening of the shortest shortwave bands."   
      
   Here are some solar flare updates:   
      
   https://bit.ly/3xvycJO   
      
   https://bit.ly/3O0re6B   
      
   Thanks to K5EM of the Western Washington DX Club for this study of   
   sporadic-E:   
      
   https://bit.ly/39zqIxk   
      
   Here is some information about the Maunder Minimum:   
      
   https://bit.ly/3QubESn   
      
   Go to https://www.spaceweather.com and look for an article that   
   appeared June 15-16 titled "Mapping a Magnetic Superstorm."   
      
   Look for this fascinating map:   
   https://www.spaceweather.com/images2022/12jun22/resistivity.jpg .   
      
   It purports to show which areas are more vulnerable to effects from   
   geomagnetic storms due to variations in ground and infrastructure   
   conductivity.   
      
   Next weekend is ARRL Field Day, a favorite operating activity for   
   many of us. The current outlook shows modest solar flux and perhaps   
   slightly elevated geomagnetic activity. Predicted solar flux for   
   June 24-26 is 136, 100 and 100, with planetary A index at 5, 10 and   
   8. Field Day starts on Saturday, but it is worth looking at   
   predictions for Friday.   
      
   Look for an update in next week's Propagation Forecast Bulletin   
   ARLP025. Field Day rules are at, http://www.arrl.org/field-day .   
      
   A few days ago, Dr. Tamitha Skov, WX6SWW, posted this:   
      
   https://youtu.be/pv4QmVfz95A   
      
   If you would like to make a comment or have a tip for our readers,   
   please email the author at, k7ra@arrl.net.   
      
   For more information concerning shortwave radio propagation, see   
   http://www.arrl.org/propagation and the ARRL Technical Information   
   Service 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/ .   
      
   Instructions for starting or ending email distribution of ARRL   
   bulletins are at http://arrl.org/bulletins .   
      
   Sunspot numbers for June 9 through 15, 2022 were 17, 33, 41, 63, 96,   
   121, and 149, with a mean of 74.3. 10.7 cm flux was 106.4, 110.5,   
   112.1, 121.3, 131.5, 145.5, and 140, with a mean of 123.9. Estimated   
   planetary A indices were 5, 5, 8, 9, 13, 8, and 20, with a mean of   
   9.7. Middle latitude A index was 6, 6, 10, 12, 14, 10, and 18, with   
   a mean of 10.9.   
   NNNN   
   /EX   
   --- SBBSecho 3.15-Win32   
    * Origin: The Thunderbolt BBS - Little Rock, Arkansas (1:2320/33)   
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