QST de W1AW
Propagation Forecast Bulletin 49 ARLP049
>From Tad Cook, K7RA
Seattle, WA December 1, 2003
To all radio amateurs
SB PROP ARL ARLP049
ARLP049 Propagation de K7RA
At the end of this bulletin are the numbers for last week, as
promised in Propagation Forecast ARLP048, issued on November 26.
This reporting period (through last Wednesday, November 26) had
average daily sunspot numbers over twice the value for the previous
week, and average daily solar flux nearly 60 points higher.
The big upset during the last reporting period was the planetary A
index of 117 on November 20. This happened when the energy from a
coronal mass ejection swept over earth while the interplanetary
magnetic field pointed south, leaving the earth's magnetic field
vulnerable. The coronal mass ejection causing all the havoc was from
sunspot 484, and occurred on November 18 around 0800z.
The recent recurrence of large sunspots has subsided with sunspots
484, 486 and 488 rotating off the visible solar disk. The sunspot
number remains relatively high due to a number of smaller sunspots
scattered across the solar surface. Solar flux should decline over
the next few days to 145, 130, 130, 125 and 120 for Friday through
Monday, December 1-5. Solar flux and sunspot numbers may reach a
minimum for the short term around December 8 before rising again to
current levels after the middle of the month.
This last weekend's CQ Worldwide CW DX Contest experienced some nice
conditions. Geomagnetic indices were very quiet, with the
mid-latitude A index at 4 and 7, and K indices as low as 1, and even
0 on the two days prior. Geomagnetic conditions should remain
moderate through this week, but could rise again around December
Average daily solar flux and sunspot numbers for November were a bit
lower than October, but October's numbers were higher than recent
months. Average daily sunspot numbers for November 2002 through
November 2003 were 159.8, 144.8, 150.0, 87.9, 119.7, 114.3, 89.6,
118.4, 132.8, 114.3, 82.6, 118.9 and 103. Average daily solar flux
values for the same months were 168.7, 157.2, 144, 124.5, 133.5,
126.8, 116.6, 129.4, 127.7, 122.1, 112.2, 155.5, and 140.8.
For more information about propagation and an explanation of the
numbers used in this bulletin see the Propagation page on the ARRL
Web site at www.arrl.org/tis/info/propagation.html.
Sunspot numbers for November 20 through 26 were 118, 131, 123, 158,
149, 202 and 209 with a mean of 155.7. 10.7 cm flux was 175.2, 177,
176.2, 178.2, 177.3, 170.7 and 170.9, with a mean of 175.1.
Estimated planetary A indices were 117, 39, 22, 21, 12, 13 and 9,
with a mean of 33.3.
If this is a second window, opened from http://hfradio.org, close this window when you are done with this news article