‰ Now 18 WPM transition file follows ‰
The past few days have had very stable geomagnetic conditions.
After unsettled to active geomagnetic indicators on March 26 to 28,
conditions quieted down dramatically. Combined with the nearly two
week run of sunspots and the Spring season, this makes for good HF
conditions. There were actually three sunspots, beginning on March
23 with the first one and a sunspot number of 14. March 24 and 25
each brought one new spot, and the sunspot number rose to 35 and 52
on those days. Activity peaked between March 26 to 29, with daily
sunspot numbers of 63, 57, 63 and 50. On Thursday April 3, the
sunspot number was back to 14 again, as one by one, the three spots
drifted from view. Todays sunspot number may be back to 0, and it
may stay that way until April 18 to 20. Conditions were remarkably
quiet on April 2 and 3, with many periods having a K index of 0, no
matter the latitude. On April 2 near Fairbanks, Alaska the College
K index as measured by the local magnetometer was 0 during all eight
three hour periods. Of course, this resulted in an A index for the
day of 0. You can go to the swpc.noaa.gov web site to see the K
index and A index for the past 30 days, as measured at
Fredericksburg, Virginia and Fairbanks, Alaska, and the Planetary
index, derived from a number of predominately higher latitude
magnetometers. With eight K index measurements per day, times three
indexes, times 30 days, you will see over 700 readings. This
weekend, April 5 and 6, will probably see the return of solar wind
and associated geomagnetic activity. The predicted Planetary A
index for April 4 to 13 is 10, 15, 15, 12, 12, 12, 12, 10, 5 and 5.
Geophysical Institute Prague predicts quiet to unsettled conditions
for April 4, active conditions for April 5, unsettled to active
April 6, unsettled April 7, unsettled to active April 8, and
unsettled April 9 and 10. Because we now have all sunspot numbers
for March, we can take another look at our three month moving
average to try to spot the sunspot minimum. The latest number, 8R4
for February 2008, is the average for all the daily sunspot numbers
from January, February and March. We simply add up all the daily
sunspot numbers, the sum is 763, and divide by the number of days,
91, to get an average of 8R3846, which we approximate as 8R4. These
number can be found in teleprinter and packet versions of
Propagation Forecast Bulletin ARLP015. Sunspot numbers were 57, 63,
50, 41, 45, 25, and 24 with a mean of 43R6. 10R7 cm flux was 84R8,
82R9, 82R6, 80R5, 79R2, 77R8, and 75R9 with a mean of 80R5.
Estimated planetary A indices were 31, 21, 8, 8, 4, 4 and 1 with a
mean of 11. Estimated mid latitude A indices were 19, 13, 6, 6, 2,
5 and 1, with a mean of 7R4‚
‰ End of 18 WPM transition file ‰