QST de W1AW
Propagation Forecast Bulletin 22 ARLP022
>From Tad Cook, K7VVV
Seattle, WA May 29, 1998
To all radio amateurs
SB PROP ARL ARLP022
ARLP022 Propagation de K7VVV
Solar indices were down this week, as they have been during the past few weeks. The sunspot number is half what it was the previous week, and the solar flux was down over 16 points. So far this month the average flux is running about the same as April and March, when it took a jump of about 16 points over January and February.
Solar flux is expected to peak over the next two days (Friday and Saturday) at 98, then drift to 96 on Sunday, then go below 90 after June 7. Flux values should drift above 90 around June 18 and to the mid-nineties in the week prior to the end of June.
During June we will be experiencing more summer-like HF conditions, with weaker daytime signals and higher noise due to increased thunderstorm activity in the northern hemisphere. With less hours of darkness and more storms, look for poorer conditions on 160 and 80 meters. Although 20 meters has been the best DX band around the clock, there is a good chance that solar activity will move higher this summer, and 15 meters could become the best daylight band for the season.
There was a solar flare during early hours UTC on May 28, but it is not expected to affect geomagnetic indices. About 12 hours earlier there was some activity that could cause a rise in geomagnetic activity on May 30 or 31. Look for very quiet geomagnetic conditions around June 9-13 and possibly on June 15 and 18.
There were a couple of errors in last week's bulletin ARLP021 regarding VHF openings. Concerning W1LP and an opening on six meters, it was really a two meter tropo opening. Also the W1JJM report of EA7 and CT3 signals was for ten meters, not six.
For this week, WA5JCI in Texas reports the best tropo openings in years, when he worked several Gulf Coast states, and then heard Mexico on a local two meter repeater. Also, N0JK in Kansas worked a number of Gulf Coast and Midwest states on 2 meter tropo, and heard KT4AL in Florida on 432 MHz.
Sunspot Numbers for May 21 through 27 were 29, 26, 47, 41, 57, 49 and 49 with a mean of 42.6. 10.7 cm flux was 89, 87.4, 90.3, 95.6, 92.3, 92.5 and 94, with a mean of 91.6, and estimated planetary A indices were 14, 8, 13, 16, 15, 8, and 7, with a mean of 11.6.