TZUTC: -0500   
   MSGID: 585.fidonet-ls_arrl@1:2320/33 29170fe4   
   PID: Synchronet 3.20a-Win32 master/777fb6d8b Jun 13 2023 MSC 1929   
   TID: SBBSecho 3.20-Win32 master/777fb6d8b Jun 13 2023 MSC 1929   
   BBSID: TBOLT   
   CHRS: ASCII 1   
   SB PROP @ ARL $ARLP028   
   ARLP028 Propagation de K7RA   
      
   ZCZC AP28   
   QST de W1AW    
   Propagation Forecast Bulletin 28  ARLP028   
   From Tad Cook, K7RA   
   Seattle, WA  July 14, 2023   
   To all radio amateurs   
      
   SB PROP ARL ARLP028   
   ARLP028 Propagation de K7RA   
      
   "GEOMAGNETIC DISTURBANCE WARNING ISSUED AT 0713UT/13 JULY 2023 BY   
   THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE.   
      
   A glancing CME impact is expected late on 13-July and another CME   
   impact is expected early on 15-July. These impacts present the   
   possibility of geomagnetic storm activity over 13-15 July."   
      
   We saw a welcome rise in solar activity this reporting week, July   
   6-12.   
      
   Referencing the previous seven days, average daily sunspot numbers   
   rose from 126.1 to 181.9, while average daily solar flux increased   
   from 164.5 to 179.4. On July 13 the solar flux was 202.9, well above   
   the average for the previous seven days.   
      
   Geomagnetic indicators did not change much, average planetary A   
   index going from 7.3 to 8.6 and average daily middle latitude A   
   index from 8 to 8.1.   
      
   The most active day was July 7 when University of Alaska's college A   
   index was 40.  The middle latitude A index on that day was only 11.   
   The college A index is from a magnetometer in Fairbanks.   
      
   What is the outlook for the next month?   
      
   Predicted solar flux looks great over the next few days, at 200,   
   202, 198, 200, and 204 on July 14-18, 202 on July 19-21, 160 on July   
   22-23, 155 on July 24-25, 160 on July 26-27, 165 on July 28-29, 170   
   on July 30-31, 165 on August 1-4, 170 on August 5, 175 on August   
   6-7, 170 on August 8, then 165 on August 9-11, 170 on August 12, 175   
   on August 13-14, 170 on August 15-17, and 160 on August 18-19.   
      
   Predicted planetary A index is 10 on July 14, 5 on July 15 through   
   August 2, then 10, 8 and 5 on August 3-5, then 8, 8, 5, 8 and 8 on   
   August 6-10, 5 on August 11 through the end of the month.   
      
   On July 12, Spaceweather.com reported:   
      
   "A new hyperactive sunspot is producing M-class solar flares every   
   few hours. This is causing shortwave radio blackouts around all   
   longitudes of our planet. If current trends continue, an X-flare   
   could be in the offing."   
      
   See Spaceweather.com for updates.   
      
   Weekly Commentary on the Sun, the Magnetosphere, and the Earth's   
   Ionosphere July 14-20, 2023 from OK1HH.   
      
   "Over the past week, we were surprised by two large groups of spots   
   that appeared on the eastern limb of the solar disk.   
      
   The first of these, AR3363, emerged in the southeast. Although it   
   remained large, there was nothing significant going on. Its opposite   
   was AR 3372 a few days later, which produced moderate-sized flares   
   almost daily.   
      
   In both cases, helioseismic echoes from the sun's far side suggested   
   that it may be the leading edge of a large active region.   
      
   But there was no indication that these would be areas with a   
   diametrically different type of activity.   
      
   The images of the two groups of spots were large enough to be   
   observed by the Mars rover Perseverance. Because of Mars' position,   
   it saw them a few days earlier than a terrestrial observer. For the   
   record: Perseverance observes the Sun daily, but mainly so that it   
   can tell from the drop in brightness that a Martian dust storm is   
   approaching.   
      
   AR3372 activity is increasing, while on July 11 and 12 several   
   M-class solar flares (some with CMEs) have already occurred (X-class   
   flare appeared to be imminent). In particular, it was almost certain   
   that the Earth's magnetic field activity would increase in the   
   following days. The probability of magnetic storms increased   
   significantly as AR3372 rotated more and more toward the Earth."   
      
   Carl, K9LA had comments on the OK1HH report from last week.   
      
   "There have been many papers in recent years that have looked at the   
   trends in ionospheric parameters over the past decades. Although the   
   changes are small, they do show up in ionosonde data after much math   
   to eliminate solar activity and geomagnetic field activity. These   
   results show both positive and negative trends in the F2 region   
   electron density, likely due to neutral atmosphere dynamics and   
   electrodynamics that could give regional differences.   
      
   An interesting paper in 2008 Geophysical Research Letters modeled   
   the increased levels of CO2 (global warming) in the atmosphere   
   versus the impact on the ionosphere.   
      
   See: https://bit.ly/3OaThCC   
      
   They used 2000 as the baseline with 365 ppmv of CO2, and doubled the   
   amount of CO2 for the year 2100. Their results showed that electron   
   densities in the E and F1 region would increase a couple percent in   
   2100 while the height of the E region peak would decrease a couple   
   km. In the F2 region, the electron density would decrease by several   
   percent in 2100 while the height of the F2 region would decrease 10   
   or so km."   
      
   Thanks to reader David Moore for this, on aurora hype:   
      
   https://bit.ly/44ovzsh   
      
   Flare video (with music.)    
      
   https://www.youtube.com/watch?v=aghiHieqCZQ   
      
   Huge sunspot:  https://bit.ly/44EcqTz   
      
   Tamitha Skov reports:  https://youtu.be/nwtCBH04bIg   
      
   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 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 .   
      
   Also, check this article from September, 2002 QST:   
      
   https://www.arrl.org/files/file/Technology/tis/info/pdf/0209038.pdf   
      
   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 July 6 through 12, 2023 were 149, 147, 167, 183,   
   181, 227, and 219, with a mean of 181.9. 10.7 cm flux was 157.6,   
   161.4, 160.5, 179.2, 190.6, 213.5, and 193.3, with a mean of 179.4.   
   Estimated planetary A indices were 11, 18, 8, 4, 5, 8, and 6, with a   
   mean of 8.6. Middle latitude A index was 11, 16, 6, 4, 6, 8, and 6,   
   with a mean of 8.1.   
   NNNN   
   /EX   
   --- SBBSecho 3.20-Win32   
    * Origin: The Thunderbolt BBS - Little Rock, Arkansas (1:2320/33)   
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