SB PROP @ ARL $ARLP003 ARLP003 Propagation de K7RA ZCZC AP03 QST de W1AW Propagation Forecast Bulletin 3 ARLP003 >From Tad Cook, K7RA Seattle, WA January 21, 2005 To all radio amateurs
SB PROP ARL ARLP003 ARLP003 Propagation de K7RA This has been a very active week for solar flares and geomagnetic storms. Average daily sunspot number rose over 57 points this week to 89, and average daily solar flux was up nearly 43 points to 132.7, when compared to the previous week. The average daily planetary A index more than doubled, from 17.9 to 36.6. Huge sunspot 720 provided lots of excitement over the past week. Clay Evans from Colorado wrote to say that on January 14 he was driving to work near Boulder, and through the heavily filtered clouds he could see a large dark spot on the sun. This was probably sunspot 720. Two large flares erupted from this sunspot on Saturday, January 15. Over the next few days the geomagnetic numbers bumped up dramatically, with a planetary A index for January 17-19 of 63, 72 and 62. The high latitude collage A index was 114, 136 and 106 for those same three days. On Monday, January 17 another big flare blasted in our direction. It peaked around 0950z. As sunspot 720 moves off the center of the visible solar disk, more flares erupted, including a huge X7-class event on Thursday, January 20. The energy could sweep past earth today (January 21). This flare was the largest of the past year and triggered the largest radiation storm in the current 11 year solar cycle. This radiation storm hasn't yet resulted in a geomagnetic storm here as of the writing of this bulletin on Thursday night. Currently the prediction is for a planetary A index of 25, 20 and 20 for January 21-23, but this could be higher depending on how direct the radiation hits earth. With sunspot 720 moving beyond view, daily solar flux values are expected to dip below 100 around January 23-24. If you would like to comment or have a tip, email the author at, [EMAIL PROTECTED] For more information concerning propagation and an explanation of the numbers used in this bulletin see the ARRL Technical Information Service propagation page at, http://www.arrl.org/tis/info/propagation.html. Sunspot numbers for January 13 through 19 were 77, 65, 100, 99, 107, 109 and 66 with a mean of 89. 10.7 cm flux was 115.6, 129.8, 144.9, 144.5, 137.5, 124.3 and 132.5, with a mean of 132.7. Estimated planetary A indices were 13, 12, 22, 12, 63, 72 and 62 with a mean of 36.6. Estimated mid-latitude A indices were 10, 11, 11, 10, 27, 35 and 31, with a mean of 19.3. NNNN /EX ---------------------------------------------------------- Archives http://www.mail-archive.com/dx-news@njdxa.org THE DXR is sponsored by the North Jersey DX Association. Please visit our website: http://www.njdxa.org/index.php scroll to bottom for subscribe/unsubscribe options ----------------------------------------------------------
