K7RA Propagation Bulletin #31 (updated on: 31/Jul/15)
SB PROP @ ARL $ARLP031 ARLP031 Propagation de K7RA ZCZC AP31 QST de W1AW Propagation Forecast Bulletin 31 ARLP031 From Tad Cook, K7RA Seattle, WA July 31, 2015 To all radio amateurs SB PROP ARL ARLP031 ARLP031 Propagation de K7RA At 0132 UTC on July 30 the Australian Space Forecast Center issued a geomagnetic disturbance warning, saying a high speed solar wind from a recurring coronal hole is expected to raise geomagnetic activity levels to minor storms on July 31 and August 1. They predict quiet to minor storm levels on July 31 and minor storm declining to unsettled conditions on August 1. Solar activity currently remains in the doldrums, with average daily sunspot numbers rising just 4.5 points to 47.9 during the July 23 to period from the prior week. Average daily solar flux over the same periods rose just 1.5 points to 96.4. When I look at the solar disc displayed at http://spaceweather.com/ I count six numbered sunspot groups, but they are not magnetically complex, and the types of radiation we need to energize our ionosphere is weak. The most active geomagnetic day was July 23, when the planetary A index was 23 and the mid-latitude A index was 21. That day there was a mild geomagnetic storm caused by a coronal mass ejection that did not hit earth directly. Predicted solar flux is 105 on July 31 through August 2, 110 on August 3 to 5, 115 on August 6, 110 on August 7, 100 on August 8 and 9, 95 on August 10 to 13, then 90 and 85 on August 14 and 15, and 100 on August 16 and 17. Solar flux peaks at 115 on August 28 to 31, then drops below 100 after September 5. Predicted planetary A index is 18 on July 31, 24 on August 1, then 16, 12 and 8 on August 2 to 4, then 5, 8 and 20 on August 5 to 7, then 15 on August 8 and 9, and 8 on August 10, 5 on August 11 to 15, 10 on August 16, 5 on August 17 and 18, then 15 and 10 on August 19 and 20, and 5 on August 21 to 23. OK1MGW predicts the geomagnetic field will be active to disturbed on July 31 and August 1, quiet to active August 2, mostly quiet August 3 to 5, quiet to active August 6, active to disturbed August 7 and 8, quiet to active August 9, quiet to unsettled August 10 and 11, quiet August 12 to 14, mostly quiet August 15, quiet to unsettled August 16, mostly quiet August 17, quiet to active August 18, quiet to unsettled August 19 to 22, and mostly quiet August 23 to 26. He expects increased solar wind on July 31 through August 3, and again on August 6 to 9. Rich Camp, WA7VGN of Las Vegas, Nevada wanted to be sure meteor showers also occur during daylight. Yes, they do, and you can make contacts via meteor scatter day and night. Jon Jones, N0JK passed along a good resource for meteor scatter, Ping Jockey Central: http://www.pingjockey.net/cgi-bin/pingtalk Jon mentioned this will be a great tool for checking activity during the upcoming Perseids Meteor shower, which is August 11 to 14 this year. Jon also passed along some sporadic-E news: "The summer 2015 North America Sporadic E skip season is winding down. Usually the peak period is around the summer solstice through the first week to 10 days of July. Some late season July Es continued. On July 21, PR8ZX GI64 in Brazil worked into the Midwest on 6 meters and was spotted 599 by K2DRH at 2239z. This was multi-hop Es to the geomagnetic equator. A strong 6 meter opening between Arizona, California and Washington State to Japan took place July 24 and 25. On the July 26, CO8LY FL20 worked into the Midwest and Rocky Mountain states via double hop Es. Spotted by K0GU DN70 and NW0W EM47 until 1650z. I logged him on 50.108 MHz at 1758z." Jon also passed along this late news: "July 30, J69MV, VP2ETE, FG8OJ and KV4FZ were in to IA, MO, OK and W4 around 1630z via double hop E-skip on 50 MHz." Check this map for live lightning detection across North America: http://www.blitzortung.org/Webpages/index.php?lang=en&page_0=30 This was passed on by Dick Bingham, W7WKR who lives way off the grid at Stehekin, Washington, which is at the northwest end of Lake Chelan. He advises making sure Strikes, Detectors Used and Sound are turned on for the lightning app. Also check these pages: http://www.blitzortung.org/Webpages/index.php?lang=en&page=2 http://www.usatoa.com/ Pierre Desjardins, VE2PID of Sherbrooke, Quebec asked about the predicted International Sunspot Number at http://1.usa.gov/1HOVlDP and what the numbers in parenthesis mean. The numbers above the parenthesis are predicted smoothed international sunspot numbers, which use a 13-month average. A zero means there is zero uncertainty about the number, because all of the data used to calculate this smoothed number are known values. But as we move into the future, there is more uncertainty. For the latest month, we already know half the data used to calculate the average, but the other half of the data is predicted. So the higher numbers in parenthesis indicate greater uncertainty. Rob Steenburgh, AD0IU who works as a space weather forecaster at NOAA said the predictions here are from the McNish-Lincoln technique, from a paper published in 1949. The method is described here: http://1.usa.gov/1MBc4l8 Rob is checking with a colleague to find out exactly what the numbers represent and perhaps the scale used. For more information concerning radio propagation, see the ARRL Technical Information Service at http://arrl.org/propagation-of-rf-signals. For an explanation of the numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere. An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation. More good information and tutorials on propagation are at http://k9la.us/. My own archives of the NOAA/USAF daily 45 day forecast for solar flux and planetary A index are in downloadable spreadsheet format at http://bit.ly/1VOqf9B and http://bit.ly/1DcpaC5 . Click on "Download this file" to download the archive and ignore the security warning about file format. Pop-up blockers may suppress download. I've had better luck with Firefox than IE. Monthly propagation charts between four USA regions and twelve overseas locations are at http://arrl.org/propagation. Instructions for starting or ending email distribution of ARRL bulletins are at http://arrl.org/bulletins. Sunspot numbers for July 23 through 29 were 27, 54, 41, 38, 53, 56, and 66, with a mean of 47.9. 10.7 cm flux was 89.4, 92.2, 94, 97, 100.1, 101.1, and 100.7, with a mean of 96.4. Estimated planetary A indices were 23, 7, 9, 8, 11, 9, and 5, with a mean of 10.3. Estimated mid-latitude A indices were 21, 6, 9, 9, 13, 9, and 7, with a mean of 10.6.
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