ZCZC AP45
QST de W1AW
Propagation Forecast Bulletin 45 ARLP045
From Tad Cook, K7VVV
Seattle, WA November 1, 2002
To all radio amateurs
SB PROP ARL ARLP045
ARLP045 Propagation de K7VVV
Thanks to Carl Luetzelschwab, K9LA for writing last week's Propagation Forecast bulletin.
Carl mentioned a major geomagnetic storm a week ago caused by a high speed solar wind from a coronal hole. High latitude K indices went as high as 7 over six 3-hour periods from October 24-26, with a College A index at 76 and 69 for Thursday and Friday. Conditions were starting to stabilize over the weekend, but this must have had a negative impact on the CQ Worldwide DX Phone Contest.
This weekend is the ARRL CW Sweepstakes, a great old domestic contest. The beginning of the weekend may not be bad, but a solar wind stream on Sunday could cause some problems for HF operators. The planetary A index is expected to be 12 on Friday and Saturday, and around 20 on Sunday and Monday. Since this is a domestic contest, there won't be any problem with disruptions on the polar path to Europe, but it could affect communications with Northern Canada.
Average sunspot numbers were down nearly 12 points this week and average solar flux declined by 13 points. Solar flux is expected to increase, going above 180 again by November 6. Heading into November with hours of darkness increasing in the Northern hemisphere expect the upper HF bands to close earlier and nighttime activity moving to lower frequencies.
Sunspot numbers for October 24 through 30 were 149, 151, 143, 120, 143, 168, and 182, with a mean of 150.9. 10.7 cm flux was 160.3, 172.9, 158, 157.1, 158.3, 161.6, and 167.7, with a mean of 162.3. Estimated planetary A indices were 47, 40, 27, 22, 17, 16, and 19, with a mean of 26.9.