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ARRL Propagation Bulletin ARLP046 (2001)

ARLP046 Propagation de K7VVV

QST de W1AW  
Propagation Forecast Bulletin 46  ARLP046
From Tad Cook, K7VVV
Seattle, WA  November 9, 2001
To all radio amateurs 

ARLP046 Propagation de K7VVV

The big news this week is the huge geomagnetic storm that hit on
Tuesday. Conditions were good last weekend for the ARRL CW
Sweepstakes, but at 0150z on November 6 energy from a coronal mass
ejection hit the earth's magnetic field. Planetary A indices rose to
8 and then 7 for several 3-hour reporting periods, and the planetary
A index for Tuesday was a very high 112, indicating a severe
geomagnetic storm.

Results included not only awful HF radio conditions, but dramatic
auroral displays as far away as Southern California and Alabama.
But by late Tuesday the radiation storm had subsided.

The Kansas City Star reported that local residents, unfamiliar with
aurora borealis, kept law enforcement busy quieting their fears of a
chemical spill or a ''nuclear death cloud.'' The same article quoted
Bill Murtagh of the NOAA Space Environment Center, saying that this
event might be the 6th or 7th largest in the last 10 years.

Average daily sunspot numbers fell this week by over 44 points, but
average daily solar flux actually rose three points. On Wednesday
solar flux jumped over 31 points to 268.6, then dropped 21 points on
Thursday. Over the next few days, Friday through Monday, solar flux
is predicted to be 245, 250, 250 and 255, and the planetary A index
is predicted at 10, 15, 15, and 15, indicating unsettled conditions.
Right now there is a growing sunspot moving into view, sunspot 9690,
which is now about 10 earth diameters long.

Check out a fascinating story titled ''What Lies Beneath A
Sunspot,'' which you can find on NASA's Science web site at .

Sunspot numbers for November 1 through 7 were 157, 164, 162, 186,
159, 189 and 230 with a mean of 178.1. 10.7 cm flux was 235.6,
213.5, 216, 227.3, 234.6, 237.4 and 268.8, with a mean of 233.3, and
estimated planetary A indices were 25, 6, 3, 7, 13, 112 and 15 with
a mean of 25.9.


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