ARLP032 Propagation de K7VVV:
August 6, 1999

Propagation Forecast Bulletin 32 ARLP032
From Tad Cook, K7VVV
Seattle, WA August 6, 1999
To all radio amateurs

ARLP032 Propagation de K7VVV

Solar flux and sunspot numbers increased again last week, with average sunspot numbers up over 52 points to 219.3 and average solar flux up over 27 points to 206.9. The solar flux of 216.3 on Sunday is a new high for the current cycle, besting the June 30, 1999 record of 209.5 by almost 7 points. The last time solar flux was higher was in cycle 22, when the February 29, 1992 number was 218. To see recent trends graphically, check the websites or

If it weren't for a major geomagnetic storm, this activity would mean better propagation on the high end of the HF bands. Last Friday was a really rough day geomagnetically, with a planetary A index of 36. But this made things interesting for VHF operators who took advantage of an aurora

For this weekend, look for a solar flux of 170, 165 and 160 for Friday through Sunday, and moderate geomagnetic conditions with a planetary A index of 10, 8 and 8.

Beyond the weekend, look for a solar flux below 10 by August 10, with the current numbers bottoming out around 135 August 11-14. Flux values should be up to 150 again around August 18, 170 by August 21, and 200 around August 25-29.

Watch for disturbed geomagnetic conditions returning around August 18.

Sunspot numbers for July 29 through August 4 were 226, 218, 220, 267, 210, 217 and 177 with a mean of 219.3. 10.7 cm flux was 202.4, 205.9, 200.6, 216.3, 212.5, 210.7 and 200.1, with a mean of 206.9, and estimated planetary A indices were 10, 36, 21, 9, 9, 8 and 11, with a mean of 14.9.

Path projections for this week are from the New York City area.