ARLP025 Propagation de K7VVV:
June 23, 2000

Propagation Forecast Bulletin 25 ARLP025
From Tad Cook, K7VVV
Seattle, WA June 23, 2000
To all radio amateurs

ARLP025 Propagation de K7VVV

Average solar flux and sunspot numbers rose slightly this week, and geomagnetic indices were lower. Planetary and mid-latitude A indices have been mostly in the single digits. Unfortunately, geomagnetic conditions may be a bit more active for Field Day this weekend. The predicted planetary A index for Friday through Tuesday is 15, 15, 20, 20 and 12, but no major disturbance is likely. Solar flux for the same period is expected to be around 175, 175, 170, 165 and 165, and should begin rising again around July 1. The short term outlook is for flux values to slowly rise and then peak around 200 before the middle of next month.

It looks like the best band will be 40 meters. There is also a possibility of 10 meter sporadic E skip openings during the day.

Sunspot numbers for June 15 through 21 were 261, 252, 211, 250, 194, 219 and 226 with a mean of 230.4. 10.7 cm flux was 202.4, 197.5, 193.1, 187.6, 178.4, 183.7 and 188, with a mean of 190.1, and estimated planetary A indices were 20, 9, 10, 11, 9, 9 and 8, with a mean of 10.9.

NASA has an article this week on a proposed model for better predicting the arrival time of the effects from Coronal Mass Ejections. You can see the NASA article at and see more info from a solar physics meeting at

Here is a forecast for this Field Day weekend.