ZCZC AP19
QST de W1AW
Propagation Forecast Bulletin 19 ARLP019
From Tad Cook, K7VVV
Seattle, WA May 10, 2002
To all radio amateurs
SB PROP ARL ARLP019
ARLP019 Propagation de K7VVV
Carl Luetzelschwab, K9LA is filling in this week for Tad Cook, K7VVV.
This report is for the period Friday May 3 through Thursday May 9.
Solar activity was at low levels for most of the period. May 7 did see moderate activity due to an M1 flare. A full halo CME was associated with this flare.
Geophysical activity ranged from quiet to unsettled over the period. The Ap index was below 11 throughout the period.
The ACE (Advanced Composition Explorer) satellite indicated the passage of a weak shock (assumed to be the result of the CME associated with the May 7 M1 flare) at around 0900z on May 9. The Bz component (strength of the magnetic field in the north-south direction) of the IMF (Interplanetary Magnetic Field) remained north, resulting in minimal impact from the CME.
As we progress into summer in the northern hemisphere, expect seasonally lower F2-region MUFs. But summer also brings the increased probability of sporadic E, so keep your ears tuned for 6-meter openings.
Sunspot numbers for May 2 through 8 were 187, 242, 271, 317, 226, 217, and 249, with a mean of 244.1. 10.7 cm flux was 169, 179.1, 189.5, 180, 190.8, 186.8, and 186.6, with a mean of 183.1. Estimated planetary A indices were 7, 7, 8, 8, 11, 11, and 11, with a mean of 7.