ZCZC AP11
QST de W1AW
Propagation Forecast Bulletin 11 ARLP011
From Tad Cook, K7VVV
Seattle, WA March 12, 1999
To all radio amateurs
SB PROP ARL ARLP011
ARLP011 Propagation de K7VVV
Average solar flux was about the same this week compared to last, rising less than 4 points. Average sunspot numbers were identical over the same two periods. Solar activity rose until the end of last week, and fell this week, providing the close averages.
Geomagnetic activity has been way up, causing aurora and lots of interesting VHF propagation. The most active day in the past week was Tuesday, when the planetary A index reached 31, and planetary K indices as high as 6. VE6XT reported that Tuesday this was the ninth consecutive night with aurora in Western Canada. On that same day a number of stations reported good DX openings on 6 meters, with many of South American stations worked by U.S. hams. AJ4Y reported that South Americans on 6 meters, including many LU stations, were sounding like 10 meters in a DX contest.
On March 9 and 10 ZL3TTC noted that he worked an XE1 and a pile of JA stations on 6 meters. Signals were very strong.
In other news, several people sent copies of a wire service story about spaces scientists announcing that an S shaped structure on the face of the sun can be used to predict coronal mass ejections. These eruptions cause the geomagnetic upsets of recent days. The S shaped image can be detected with x-ray satellites, and this allows predictions of geomagnetic storms to be made several days earlier than current methods.
Someone wanted to know the latest forecast telling when this solar cycle should peak. The last forecast shows a peak in smoothed solar flux around this time next year at around 210.
Joe Reisert, W1JR writes that he thinks 1999 has been a good year so far for band conditions. He keeps a yearly count of DXCC countries worked, and in a typical year the number is 275. In 1998 he worked 289 countries, and in the first two months of this year his count was 240. This is all with 100 watts.
For this weekend, expect more geomagnetic disturbances, with a planetary A index for Friday through Sunday of 12, 15 and 23. This activity is expected to continue through the next week, with A indices finally dropping to the single digits around March 20. Expect more disturbed activity on March 28 through April 3. Solar flux for this weekend is predicted at 140, 140 and 135, through Sunday.
Sunspot Numbers for March 4 through 10 were 144, 135, 136, 93, 107, 89 and 88 with a mean of 113.1. 10.7 cm flux was 144.1, 127.5, 114.4, 110, 126.9, 127.1 and 135.4, with a mean of 126.5, and estimated planetary A indices were 23, 18, 11, 25, 10, 23 and 31, with a mean of 20.1.
Here are some path projections for this weekend from Atlanta, Georgia: