ZCZC AP55
QST de W1AW
Propagation Forecast Bulletin 55 ARLP055
From Tad Cook, K7VVV
Seattle, WA December 28, 2001
To all radio amateurs
SB PROP ARL ARLP055
ARLP055 Propagation de K7VVV
(Substitute solar sage Carl Luetzelschwab, K9LA, files this week's Solar Update for Tad Cook, K7VVV, who's off for the holidays.)
Solar activity was low at the beginning of the reporting period (Dec 21 to Dec 27), with only class-C flares occurring.
Solar activity increased to high levels toward the end of the period due to many class-M flares, the biggest being an M7 proton flare on Wednesday, Dec 26. This flare produced a short duration 100-MeV proton event, and a longer duration 10-MeV proton event that is still in progress. A Polar Cap Absorption (PCA) event also occurred, reaching a peak absorption of about 9 dB at 1115 UTC on Dec 26. Accompanying the M7 flare was a Coronal Mass Ejection (CME).
Geophysical activity mostly ranged from quiet to unsettled over the reporting period.
The Penticton (British Columbia) 10.7-cm solar flux was 234 at the start of the reporting period on Friday, Dec 21, and gradually increased to 275 by the end of the period, Thursday, Dec 27.
The daily planetary magnetic index Ap was below 10 for most of the period. It is predicted to increase to around 30 on December 28 due to the December 26 CME activity. This will result in minor storm conditions, but these conditions are expected to be relatively brief.
K7VVV will be back next week with this week's sunspot numbers, solar flux numbers, and A indices.