SB PROP @ ARL $ARLP002   
   ARLP002 Propagation de K7RA   
      
   ZCZC AP02   
   QST de W1AW     
   Propagation Forecast Bulletin 2  ARLP002   
   From Tad Cook, K7RA   
   Seattle, WA  January 13, 2012   
   To all radio amateurs    
      
   SB PROP ARL ARLP002   
   ARLP002 Propagation de K7RA   
      
   Average daily sunspot numbers were up this week by a tiny bit, from   
   88.1 to 90.6, and average daily solar flux was down slightly, from   
   136.2 to 134.9.   
      
   I'm looking at recent sunspot data since May 2011 using the WA4TTK   
   Solar Data Plotter (see http://www.craigcentral.com/sol.asp) and the   
   activity had a rising trend throughout 2011 and seemed to peak   
   around mid-November, but since then has softened.   
      
   The latest daily projection from NOAA/USAF shows solar flux about 20   
   points lower than the average for the week, at 115 on January 13-15,   
   120 on January 16-20, then a jump of 25 points to 145 on January   
   21-26. It declines again, to a minimum of 135 on January 31 to   
   February 6, then rises to a peak of 165 on February 17-21.   
      
   Predicted planetary A index is 5 on January 12, 8 on January 13-14,   
   5 on January 15-17, 8 on January 18-19, and back to 5 on January   
   20-27.   
      
   Rulon Passey, W7QR of Ogden, Utah pointed out that the solar flux   
   and Ap index forecast were missing from last week's bulletin. But   
   you can get the same data, updated daily, at   
   http://www.swpc.noaa.gov/ftpmenu/forecasts/45DF.html.   
      
   It is a shame that archives of these forecasts going way back aren't   
   available. They are up for less than three weeks, or at least the   
   current ones are. But let's try something interesting. The predicted   
   solar flux of 165 for February 17-21 is rather extraordinary.  This   
   is a period of five days, and happens to be right in the middle of   
   what will be our data reporting period - February 16-22 - for   
   bulletin number 8 on February 24. If we are to take this forecast   
   literally, with a solar flux value of 160 predicted on both the   
   first and last days, that would be an average solar flux value for   
   that seven days of 163.6.   
      
   I was surprised when I searched for the last time our bulletin   
   reported an average at this level or higher.  The last time was in   
   Propagation Forecast Bulletin ARLP045, issued November 11, 2011 with   
   data from November 3-9.  Average solar flux was 173.7 and average   
   sunspot number was 153.4. But even more surprising was when I   
   searched for any previous bulletin that reported an average this   
   high or higher.   
      
   Way back on January 17, 2003, nearly nine years ago, Propagation   
   Forecast Bulletin ARLP003 reported an average solar flux of 173.6   
   and sunspot number of 200.9.  This was right before Cycle 23 plunged   
   toward the long quiet period we recently recovered from with the   
   upswing of Cycle 24.   
      
   So let's track this and see if the prediction for the period six   
   weeks from now changes, by how much, and when. I suppose this   
   prediction may be based on a return to norm, assuming that Cycle 24   
   peaks in 2013, with the fact that the recent activity for the past   
   few weeks has been lower than it was in the last months of 2011.   
      
   The current issue of Atlantic Magazine has an entertaining and   
   informative article about the Sun and space weather prediction. Read   
   it at,   
   http://www.theatlantic.com/magazine/archive/2012/01/star-power/8855/.   
      
   Last week we mentioned adjustments to the geomagnetic indices.   
   Michael Husler of NOAA sent a link to a page describing the new   
   geomagnetic products, and you can see it at   
   http://www.swpc.noaa.gov/geomag/geomag.html.   
      
   Unfortunately, due to a staff retirement in Prague, we are no longer   
   getting the updates from Geophysical Institute Prague. These updates   
   began 34 years ago in January, 1978.   
      
   If you would like to make a comment or have a tip for our readers,   
   email the author at, k7ra@arrl.net.   
      
   For more information concerning radio propagation, see the ARRL   
   Technical Information Service web page at   
   http://arrl.org/propagation-of-rf-signals. For an explanation of the   
   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. Find more good   
   information and tutorials on propagation at   
   http://myplace.frontier.com/~k9la/.   
      
   Monthly propagation charts between four USA regions and twelve   
   overseas locations are at http://arrl.org/propagation.   
      
   Instructions for starting or ending email distribution of ARRL   
   bulletins are at http://arrl.org/bulletins.   
      
   Sunspot numbers for January 5 through 11 were 99, 118, 110, 90, 90,   
   63, and 64, with a mean of 90.6. 10.7 cm flux was 141.3, 135.5,   
   140.5, 135.8, 142.3, 128.8, and 120.1, with a mean of 134.9.   
   Estimated planetary A indices were 5, 5, 5, 4, 6, 4, and 5, with a   
   mean of 4.9. Estimated mid-latitude A indices were 6, 6, 5, 5, 7, 5,   
   and 5, with a mean of 5.6.   
   NNNN   
   /EX   
      
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