[SFDXA] ARLP037 Propagation de K7RA

[Bill]

> SB PROP @ ARL $ARLP037
> ARLP037 Propagation de K7RA
> 
> ZCZC AP37
> QST de W1AW  
> Propagation Forecast Bulletin 37  ARLP037
> From Tad Cook, K7RA
> Seattle, WA  September 15, 2023
> To all radio amateurs 
> 
> SB PROP ARL ARLP037
> ARLP037 Propagation de K7RA
> 
> Like last week, eight new sunspot groups emerged this reporting
> week, September 7-13.
> 
> One appeared on September 7, another September 9, four more on
> September 10, another on September 11 and one more on September 12.
> 
> Solar activity made a nice comeback, with average daily sunspot
> numbers rising from 95.4 to 138.1, and solar flux from 137.6 to
> 159.9.
> 
> The most active geomagnetic day was September 12, when the planetary
> A index was 25. Spaceweather.com reported a "stealth CME"
> (unexpected) that had aurora visible down as far as Missouri.
> 
> Average daily planetary A index decreased from 15.4 to 10.4, and
> middle latitude numbers from 16.3 to 11.3.
> 
> The Autumnal Equinox in the Northern Hemisphere is just a week away,
> on September 22.
> 
> It seems that the next sustained short term peak in solar flux is a
> few weeks off, with values between 150 and 155 over October 12-17,
> although it is expected to reach 150 on September 23-24.
> 
> The forecast shows solar flux at 145, 148, 145 and 145 on September
> 15-18, 140 on September 19-21, 145 on September 22, 150 on September
> 23-24, 145 on September 25, 140 on September 26-27, 135 on September
> 28-30, then 130, 135, 130 and 135 on October 1-4, 140 on October
> 5-6, 135 on October 7-8, 140 on October 9, 145 on October 10-11, 150
> om October 12-13, then 155, 150, 155 and 150 on October 14-17, 145
> on October 18-19, and 150 on October 20-21.
> 
> Predicted planetary A index is 15 on September 15, 8 on September
> 16-17, then 5, 5, and 10 on September 18-20, 5, 8 and 12 on
> September 21-23, 5 on September 24-27, then 8, 12 and 8 on September
> 28-30, and 5 on October 1-8, then 15, 12, 10 and 8 on October 9-12,
> 5 on October 13-19, 12 on October 20, and 5 on October 21-24.
> 
> Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
> Ionosphere - September 15-22, 2023 from OK1HH.
> 
> "A week ago, the active sunspot group AR3414 dominated the solar
> disk. It is now on the far side of the Sun. This role has been taken
> over by AR3423, now approaching the western limb of the solar disk.
> It will be followed the next day by the slightly smaller AR3425. The
> important information is that we observe a coronal hole near both of
> them (closer to AR3425). This configuration was the likely cause of
> the surprise: Few people expected the Earth to be hit by a CME on
> September 12 at 1237 UT.
> 
> "Then a massive disturbance of the Earth's magnetic field developed.
> Its initial positive phase increased the MUF values on September 12.
> This was followed by a negative phase, which in turn caused a
> significant decrease in MUF, with worsened shortwave propagation
> conditions on 13 September. This was followed by a gradual
> improvement on 14 September, when the magnetic filament connecting
> sunspots AR3423 and AR3425 erupted. The consequence could be a G1 to
> G2 class geomagnetic storm in the Earth's vicinity on 17 September."
> 
> Jon Jones, N0JK wrote from Kansas:
> 
> "Sunday afternoon and evening (September 10-11) strong sporadic-E on
> 6 meters took place.
> 
> "This set up links to TEP on to South America.
> 
> "The hot spot seemed to be south Central Kansas and northeast
> Oklahoma. KF0M in EM17 worked many South American stations. From
> EM28, the Es was not lined up that well.
> 
> "Had many strong stations in south Texas and northern Mexico.
> Around 2250 UTC LU1MQF (FF55) and CE4MBH (FF44) appeared for a few
> minutes on 50.313 MHz FT8.
> 
> "Any sporadic-E is a treat in the September ARRL VHF contest (which
> was last weekend). With Solar Cycle 25 picking up, the Es can link
> to TEP."
> 
> An article about the Sun from IFLScience:
> 
> https://www.iflscience.com/has-part-of-the-sun-really-become-broken-70653
> 
> The latest from Dr. Tamitha Skov, WX6SWW:
> 
> https://youtu.be/S2IOBwSo_LI
> 
> Send your tips, reports, observations, questions, and comments to
> k7ra at arrl.net. When reporting observations, don't forget to tell us
> which mode you were operating.
> 
> Also, check this article from September, 2002 QST:
> 
> https://bit.ly/3Rc8Njt
> 
> 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 September 7 through 13, 2023 were 135, 123, 119,
> 167, 173, 141, and 109, with a mean of 138.1.  10.7 cm flux was
> 160.8, 160.9, 161.4, 163.9, 176.4, 153.5, and 142.6, with a mean of
> 159.9. Estimated planetary A indices were 6, 6, 8, 4, 7, 25, and 17,
> with a mean of 10.4. Middle latitude A index was 11, 8, 12, 6, 8,
> 17, and 17, with a mean of 11.3.
> NNNN
> /EX