SB PROP @ ARL $ARLP008
ARLP008 Propagation de KT7H
 
ZCZC AP22
QST de W1AW
Propagation Forecast Bulletin 8  ARLP008
>From Tad Cook, KT7H
Seattle, WA  February 25, 1994
To all radio amateurs
 
Solar activity was up last week, but so were disturbances.  
A major solar flare on February 20 blasted the Earth with 
enough protons to cause a major HF radio blackout on 
February 22.  The delay is because heavier protons travel 
slowly.  The Boulder A index rose to 42 on the 21st and 59 
on the 22nd.  The worst period was 0600z on February 22 
when the K index rose to 8.  Each point on the K index 
scale represents a huge increase in the disturbance.  A 
level of 8 is incredibly bad for HF propagation, 
especially in the higher latitudes.
 
There may be more bad news ahead.  If the solar regions 
that caused poor conditions four weeks earlier rotate into 
view again, we could experience more bad conditions around 
March 5 through 11, with the worst period around March 6 
and 7.  Solar flux should drop gradually, reaching a low 
around 90 during that period, and rising above 100 again 
by the middle of the month.
 
For the long term, expect solar flux to peak slightly over 
the next couple of months, before continuing the slide 
toward the probable solar minimum about three years from 
now.  In a year, average flux should be about 15 points 
lower than now, and 30 points lower in two years.  The 
current best guess is for the next sunspot cycle to peak 
probably in the Summer of 2000.
 
Sunspot Numbers from February 17 through 23 were 67, 77, 
54, 33, 17, 68 and 47, with a mean of 51.9.  10.7 cm flux 
was 106.4, 106.3, 108, 108, 105, 106.7 and 107, with a 
mean of 106.8.
NNNN
/EX