ZCZC AP22
QST de W1AW
Propagation Forecast Bulletin 22 ARLP022
From Tad Cook, K7RA
Seattle, WA May 30, 2003
To all radio amateurs
SB PROP ARL ARLP022
ARLP022 Propagation de K7RA
While this bulletin is being written Friday, May 30 at around 0600 UTC, a severe geomagnetic storm rages. For the past three reporting periods (three hours each), the planetary K index has been 8, indicating extremely active conditions. This is unfortunate. For some time now I've been hoping that the planetary A index would drop below 10 around May 31, but May 26 was the last day that projection showed up on the Alerts, Forecasts, and Summaries ftp site.
A late forecast at 0359 UTC on May 30 shows the projected planetary A index for May 30 through June 2 as 60, 40, 25 and 20, followed by an A of 30 for June 3-5, 35 for June 6, and 30 again on June 7.
On May 29 Earth was hit by two coronal mass ejections. One was at 1215 UTC and the other at 1900 UTC. A third coronal mass ejection may hit us on Friday, May 30. Rather than working HF, now seems a good time for 6-meter operations and observing aurora. Solar flux over the next few days (May 30 through June 2) is predicted at 145, 140, 135 and 125. It may hit 100 around June 5, then drop down around 90, rising again after June
Jim Tabor, KU5S, has just updated his program, GeoAlert Wizard. It sits in the system tray on your PC and grabs solar and geophysical date automatically off the internet. Check it out on Tabor's Web site.
For more information on propagation and an explanation of the numbers used in this bulletin see the Propagation page on the ARRL Web site.
Sunspot numbers for May 22 through 28 were 110, 87, 84, 51, 65, 116 and 116, with a mean of 89.9. The 10.7-cm flux was 118.4, 117.9, 116.8, 121.1, 125.1, 128.8 and 130.2, with a mean of 122.6. Estimated planetary A indices were 25, 21, 22, 22, 18, 26 and 36, with a mean of 24.3.
My thanks to Carl Luetzelschwab, K9LA, for handling the "Solar Update" last week.