[South Florida DX Association] ARLP003 Propagation de K7RA

[Bill Marx]

SB PROP @ ARL $ARLP003
> ARLP003 Propagation de K7RA
> 
> ZCZC AP03
> QST de W1AW  
> Propagation Forecast Bulletin 3  ARLP003
> From Tad Cook, K7RA
> Seattle, WA  January 21, 2005
> To all radio amateurs 
> 
> SB PROP ARL ARLP003
> ARLP003 Propagation de K7RA
> 
> This has been a very active week for solar flares and geomagnetic
> storms. Average daily sunspot number rose over 57 points this week
> to 89, and average daily solar flux was up nearly 43 points to
> 132.7, when compared to the previous week. The average daily
> planetary A index more than doubled, from 17.9 to 36.6.
> 
> Huge sunspot 720 provided lots of excitement over the past week.
> Clay Evans from Colorado wrote to say that on January 14 he was
> driving to work near Boulder, and through the heavily filtered
> clouds he could see a large dark spot on the sun. This was probably
> sunspot 720.
> 
> Two large flares erupted from this sunspot on Saturday, January 15.
> Over the next few days the geomagnetic numbers bumped up
> dramatically, with a planetary A index for January 17-19 of 63, 72
> and 62. The high latitude collage A index was 114, 136 and 106 for
> those same three days.
> 
> On Monday, January 17 another big flare blasted in our direction.
> It peaked around 0950z. As sunspot 720 moves off the center of the
> visible solar disk, more flares erupted, including a huge X7-class
> event on Thursday, January 20. The energy could sweep past earth
> today (January 21). This flare was the largest of the past year and
> triggered the largest radiation storm in the current 11 year solar
> cycle.
> 
> This radiation storm hasn't yet resulted in a geomagnetic storm here
> as of the writing of this bulletin on Thursday night. Currently the
> prediction is for a planetary A index of 25, 20 and 20 for January
> 21-23, but this could be higher depending on how direct the
> radiation hits earth. With sunspot 720 moving beyond view, daily
> solar flux values are expected to dip below 100 around January
> 23-24.
> 
> If you would like to comment or have a tip, email the author at,
> k7ra at arrl.net.
> 
> For more information concerning 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.
> 
> Sunspot numbers for January 13 through 19 were 77, 65, 100, 99, 107,
> 109 and 66 with a mean of 89. 10.7 cm flux was 115.6, 129.8, 144.9,
> 144.5, 137.5, 124.3 and 132.5, with a mean of 132.7. Estimated
> planetary A indices were 13, 12, 22, 12, 63, 72 and 62 with a mean
> of 36.6. Estimated mid-latitude A indices were 10, 11, 11, 10, 27,
> 35 and 31, with a mean of 19.3.
> NNNN
> /EX
>