SB PROP @ ARL $ARLP020<br />ARLP020 Propagation de K7VVV<br /><br />ZCZC AP20<br />QST de W1AW <br />Propagation Forecast Bulletin 20 ARLP020<br />>From Tad Cook, K7VVV<br />Seattle, WA May 17, 2002<br />To all radio amateurs <br /><br />SB PROP ARL ARLP020<br />ARLP020 Propagation de K7VVV<br /><br />Thanks to Carl, K9LA for writing last week's bulletin. Carl writes<br />a monthly propagation column for Worldradio, and is also the new<br />editor of the National Contest Journal.<br /><br />Solar flux and sunspot numbers declined this week. Average daily<br />sunspot numbers were off nearly 50 points and daily solar flux was<br />down a little over five points. Solar flux dropped quite<br />dramatically over the past few days, from over 190 a week ago to<br />about 183 on Sunday, 172 on Monday, 161 on Tuesday, 159 on Wednesday<br />and 158 on Thursday. The current forecast shows flux rising to 170<br />early next week.<br /><br />On Thursday an eruption on the sun near sunspot 9948 sent a coronal<br />mass ejection toward earth. This was not a powerful blast, but it<br />was earth-directed. Look for rising geomagnetic indices on Saturday<br />and Sunday, with the possibility of aurora visible from northern<br />latitudes.<br /><br />Another coronal mass ejection raised some havoc this week. It swept<br />past earth on May 11, sparking a geomagnetic storm and aurora, which<br />lasted several days. Peak activity was on May 11 when the planetary<br />A index reached 40.<br /><br />Sunspot numbers for May 9 through 15 were 244, 245, 226, 210, 168,<br />134, and 137, with a mean of 194.9. 10.7 cm flux was 190, 191, 188,<br />183.3, 172, 160.7, and 159.2, with a mean of 177.7. Estimated<br />planetary A indices were 10, 17, 40, 19, 12, 32, and 16, with a mean<br />of 20.9.<br />NNNN<br />/EX