‰ Now 18 WPM transition file follows ‰

Its a new year, and now time to review 2007 sunspot cycle
progression.  In 2006 there was a consensus that solar minimum would
occur in early 2007, but we actually may not be there still.  The
latest projection in the Weekly Preliminary Report and forecast,
which can be seen on the web, shows the bottom of the cycle between
December 2007 and April 2008.  Note the two predictions for the next
cycle, a high estimate and a low estimate, reflecting the split
consensus for the Cycle 24 prediction.  Also note the monthly
forecast issued on January 2 shows a cycle minimum for February
2008.  Exactly one year ago in Propagation Forecast Bulletin ARLP001
we wrote that 2007 would be the year well likely see the end of
sunspot Cycle 23, the beginning of Cycle 24, and the minima between
cycles.  Now a year later we might say the same about 2008.  The
yearly average of the daily sunspot numbers for 1999 to 2007 were
136R3, 173, 170R3, 176R6, 109R2, 68R6, 48R9, 26R1 and 12R8.  Average
daily solar flux for the same years was 153R7, 179R6, 181R6, 179R5,
129R2, 106R6, 91R9, 79R9 and 73R1.  Compare 2006 to 2007 above with
the last solar minimum, when in 1995 to 1997 the yearly averages of
sunspot numbers were 28R7, 13R2 and 30R7.  In February 2007 we began
calculating and tracking a 3 month moving average of daily sunspot
numbers.  This was done to try to spot trends.  A three month period
seemed like it might give us some smoothing of the often volatile
daily numbers, but much shorter than the 12 month smoothed values.
These numbers can be seen in teleprinter and packet versions of
Propagation Forecast Bulletin ARLP001.  Why is November the last
month on the list?  Because it is the center month for the latest 3
month average, which is for October through December.  If we were
instead calculating a 12 month moving average, at the end of
December the latest number would center on June 2007.  Last weeks
bulletin reported 10 meter openings, and said that E skip was
unexpected at this time of year.  Actually there is a small peak in
sporadic E propagation centered around Winter Solstice, about one
fifth to one eighth the intensity of the summer sporadic E season.
The propagation reported by K7HP occurred just hours from the
precise time of solstice.  See the web site
amfmdx.net/propagation/Es.html for an interesting treatment of E
layer propagation.  So whats up for the next week?  Sunspot 978
reappeared, and the daily sunspot numbers for Tuesday, Wednesday and
Thursday were 11, 13 and 13, while solar flux was 79R4, 79R6 and
79R3.  The US Air Force and NOAA Space Weather Prediction Center
forecast rising solar flux values of 80 for January 4 and 5, 85 for
January 6 to 8, and 90 for January 9 to 11.  This is a slight move
downward and outward.  As recently as two days ago, they were
predicting flux of 95 for January 7 to 9.  They also forecast a
planetary A index for January 4 to 10 of 10, 10, 5, 8, 8, 5 and 5.
The next unsettled to active period is predicted for January 13 and
14 with a planetary A index of 15.  After 2100z today look for an
updated forecast of solar flux and A index on the
sec.noaa.gov/ftpdir/forecasts/ web link.  Sunspot numbers were 0, 0,
0, 0, 0, 11 and 13 with a mean of 3R4.  10R7 cm flux was 72R1, 71R8,
72R7, 75, 76R7, 79R4, and 79R6 with a mean of 75R3.  Estimated
planetary A indices were 4, 2, 2, 2, 2, 3 and 1 with a mean of 2R3.
Estimated mid latitude A indices were 4, 2, 2, 3, 2, 2 and 1, with a
mean of 2R3‚


‰ End of 18 WPM transition file ‰