ZCZC AP24
QST de W1AW
Propagation Forecast Bulletin 24 ARLP024
From Tad Cook, K7VVV
Seattle, WA June 8, 2001
To all radio amateurs
SB PROP ARL ARLP024
ARLP024 Propagation de K7VVV
Solar flux is rising a little faster than forecast in last week's Propagation Forecast Bulletin ARLP023, which predicted a solar flux of 140 for June 8, 145 for June 11 and 150 by June 14. It passed 145 by June 3 and 150 by June 4. The current outlook calls for solar flux to rise to 170 on Saturday and Sunday and peak around 175 on Monday and Tuesday. There is a possibility of a dramatic drop in flux values between Thursday and Friday of next week, then another rise over the following week.
Geomagnetic conditions have been unsettled, but should quiet down with the planetary A index in the single digits over the next few days.
Solar flux and sunspot numbers probably reached a short term minimum around May 30 or 31, right between the two reporting periods from this week's bulletin and last week's. Average daily sunspot numbers for the week were down 21 points this week compared to last, and average solar flux was down a little over four points.
The High Energy Solar Spectroscopic Imager (HESSI) satellite was supposed to launch this week, but has been delayed until June 14. This is another tool for solar observers, and will be used to explore the physics of particle acceleration and energy release in solar flares. Learn more about it at http://hesperia.gsfc.nasa.gov/hessi/sheet.htm. HESSI will use germanium crystals as detectors, and is capable of downloading data at the rate of 3.5 megabits per second.
Sunspot numbers for May 31 through June 6 were 93, 120, 141, 143, 125, 160 and 170 with a mean of 136. 10.7 cm flux was 132.8, 133, 134, 145.3, 153.8, 153.4 and 157.7, with a mean of 144.3, and estimated planetary A indices were 7, 11, 21, 11, 11, 9 and 10 with a mean of 11.4.