QST de W1AW
Propagation Forecast Bulletin 46 ARLP046
From Tad Cook, K7VVV
Seattle, WA November 9, 2001
To all radio amateurs
SB PROP ARL ARLP046
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 http://science.nasa.gov/headlines/y2001/ast07nov_1.htm.
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.