ZCZC AP11
QST de W1AW
Propagation Forecast Bulletin 11 ARLP011
From Tad Cook, K7VVV
Seattle, WA March 13, 1998
To all radio amateurs
SB PROP ARL ARLP011
ARLP011 Propagation de K7VVV
Average solar flux was down less than a point last week compared to the previous week. Average sunspot numbers dropped from 73.7 to 59.1 Solar flux has risen in the past few days though. It was 101.6 on Thursday as this bulletin was written, and the flux values forecast for this weekend are 105, 105 and 110 on Friday through Sunday.
Solar flux is expected to decline below 100 after Sunday, then drop to the mid nineties by next Thursday, and up around 100 again by March 27. Unsettled geomagnetic conditions could return around March 17, 29 and April 6.
The most active solar region is number 8176, first observed six days ago with 25 sunspots. The geomagnetic field has been active recently, with the worst days on March 10 and 11, with planetary K indices as high as six.
We are still moving toward the spring equinox, but solar flux has been too low for much excitement on higher frequencies. Most 10 meter paths have been disappointing, and fans of the 28 MHz band will probably have to wait until this fall to see much action there.
Sunspot Numbers for March 5 through 11 were 42, 54, 54, 57, 49, 75 and 83 with a mean of 59.1. 10.7 cm flux was 96.7, 91.7, 91.9, 91.2, 90, 96.3 and 100.7, with a mean of 94.1, and estimated planetary A indices were 9, 6, 5, 2, 3, 25, and 28, with a mean of 11.1.