[South Florida DX Association] ARLP020 Propagation de K7RA

[Bill Marx]

QST de W1AW  
> Propagation Forecast Bulletin 20  ARLP020
> From Tad Cook, K7RA
> Seattle, WA  May 16, 2005
> To all radio amateurs 
> 
> SB PROP ARL ARLP020
> ARLP020 Propagation de K7RA
> 
> This is a special edition of the Propagation Forecast Bulletin.
> 
> On Friday the Thirteenth (May 13, 2005) at 1650z a tremendous
> explosion near sunspot 759 blasted toward earth. The impact on the
> earth's magnetic field was felt at 0230z on May 15, producing an
> extreme geomagnetic storm.
> 
> I use a service from http://www.spaceweather.com called
> "SpaceWeather PHONE." I can set parameters for alerts, and the
> service calls my cell phone when events occur, such as the planetary
> K index rising above a set value. The service rang me up so many
> times this weekend that I finally shut the phone off. I could have
> gone to the web and shut it off or raised the parameters, but at the
> time I just wanted to roll over and go back to sleep.
> 
> On Sunday, May 15 the planetary K index reached 9. This is huge.
> The middle latitude, high latitude and planetary A indexes for
> Sunday were 44, 77 and 105 respectively, all very high values. The
> planetary A index predicted for Monday, May 16 is 40. Solar flux is
> expected to stay around 100 for Monday through Wednesday, May 16-18.
> 
> Michael Shaffer, KA3JAW is currently in Tampa, Florida. On Friday,
> May 13 Michael began to scan low VHF television channels because of
> the possibility of aurora from a coronal mass ejection on May 11.
> He emailed several photos he took of his television displaying KGAN,
> channel 2, in Cedar Rapids, Iowa. He received both audio and video
> for about 30 minutes after 5:00 PM local time. The distance was
> about 1,100 miles.
> 
> Steven Smith, K6BZ of Carmichael, California wrote to ask if "in the
> early period of a new solar cycle, sunspot groups tended to form in
> the higher latitudes on the solar disk and towards the end, favored
> more equatorial latitudes." This is true, and the greater emergence
> of sunspots toward the sun's equator later in the cycle heightens
> the probability that the energy from those spots will be
> earth-directed.
> 
> If you would like to comment or have a tip, email the author at,
> k7ra at arrl.net.
> 
> For more information concerning radio propagation and an explanation
> of the numbers used in this bulletin see the ARRL Technical
> Information Service propagation page at,
> http://www.arrl.org/tis/info/propagation.html. An archive of past
> bulletins is found at, http://www.arrl.org/w1aw/prop/.
> 
> Sunspot numbers for May 5 through 11 were 50, 66, 55, 79, 106, 106
> and 117 with a mean of 82.7. 10.7 cm flux was 109.1, 110.4, 99.9,
> 101.3, 110, 119.2 and 125.3, with a mean of 110.7. Estimated
> planetary A indices were 6, 4, 10, 64, 11, 10 and 11 with a mean of
> 16.6. Estimated mid-latitude A indices were 3, 3, 10, 38, 10, 6 and
> 7, with a mean of 11.
> NNNN
> /EX
> 
>