‰ Now 18 WPM transition file follows ‰

The Army, Air Force, Navy, Marine Corps and Coast Guard are co
sponsoring the annual Military/Amateur Radio Crossband
Communications Test in celebration of the 58th anniversary of Armed
Forces Day, or AFD. Although the actual Armed Forces Day is
celebrated on the third Saturday in May, which is May 17 in 2008,
the AFD Military/Amateur Crossband Communications Test will be
conducted on May 10 to prevent conflict with the Dayton Hamvention,
scheduled for May 16 to 18.  For several weeks we expected today,
May 2 to have active geomagnetic conditions.  For instance, if you
look at a forecast from April 23 on the swpc.noaa.gov web site, it
shows an expected planetary A index for May 1 to 3 of 10, 20 and 15.
The next day, April 24 this changed to 8, 20 and 15, and on April 25
it was 10, 15 and 15.  For May 1 we see the actual planetary A index
for that day was 9, and for the following two days, the predicted
values are 10 and 12, which are much more moderate.  So obviously as
we moved closer to this date, the return of a solar wind stream
seemed less likely, although earlier today the planetary K index
rose as high as 4, indicating unsettled to active geomagnetic
conditions.  The IMF, or Interplanetary Magnetic Field, pointed
south when the K index was high, which means our planet was
vulnerable to radiation from solar flares and wind streams.  Later
the IMF pointed north, and the K index dropped to 0, which is very
quiet.  Nine planetary K index readings from 1500z May 1 through
1500z May 2 went from quiet to active to quiet again, 0, 1, 3, 3, 4,
4, 4, 3 and 0.  A solar wind stream flowing from a coronal hole is
expected to reach earth on May 5.  The expected planetary A index
for May 2 to 11 is 10, 12, 12, 8, 10, 8, 5, 5, 5 and 5.  That
forecast is from the NOAA Space Weather Prediction Center and the
U.S. Air Force.  Those numbers are from the May 1 prediction.  You
can see the May 2 prediction some time after 2100z today by changing
the last element of one of the URLs in the first paragraph from
042445DF.txt to 050245DF.txt.  That same forecast from May 1 is now
predicting a 10R7 cm solar flux reading of 70 for the next 45 days.
But on April 28 they were predicting solar flux to rise to 75 from
May 20 to 28.  The Solar Department at the Ondrejov Observatory of
the Prague Astronomical Institute, part of the Academy of Sciences
of the Czech Republic, projects a 10R7 cm solar flux range of 66 to
73 and a sunspot number range of 0 to 25 for May 2 to 8.  For the
same period Geophysical Institute Prague predicts geomagnetic
activity of unsettled to active May 2, active on May 3, unsettled
May 4 to 6, quiet to unsettled May 7, and quiet May 8.  Now that we
have all the sunspot data for April, we can take our monthly look at
our 3 month moving average of daily sunspot numbers to give us a
hint on where this cycle may be heading.  The March 08 figures are
an average of daily sunspot data from February 1 through April 30.
These numbers are available in teleprinter and packet versions of
Propagation Forecast Bulletin ARLP019.  We can see that a slight
rise in sunspot activity from October levels has flattened.
Although another digit isnt really significant, for readers who
prefer to parse their parameters more precisely, the December
through March averages may be expressed as 8R14, 8R52, 8R39 and
8R36.  Sunspot numbers were 11, 0, 0, 0, 0, 0, and 0 with a mean of
1R6.  10R7 cm flux was 70R4, 69R8, 69, 68R1, 68R5, 68R6, and 67 with
a mean of 68R8.  Estimated planetary A indices were 18, 8, 10, 10,
11, 8 and 9 with a mean of 10R6.  Estimated mid latitude A indices
were 13, 7, 5, 7, 9, 4 and 4, with a mean of 7‚

‰ End of 18 WPM transition file ‰