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K7RA's Solar Report

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Last update: Friday, 18-Aug-2017 09:00:34 GMT

SB PROP @ ARL $ARLP033
ARLP033 Propagation DE K7RA
QST DE W1AW
Propagation Bulletin 33 ARLP033 From Tad Cook, K7RA
Seattle, Washington August 18 2017
To all radio amateurs

Several readers pointed out those averages for the various indicators we track were all wrong last week. Average daily sunspot number was 12.1 instead of 5, although the rest of the text in the bulletin was correct. Likewise, average daily solar flux was 73.2 instead of 71.

And average daily planetary A index was 11.3 instead of 5, and mid-latitude A index was really 6.9 instead of 6.

The current (most recent) week, August 10-16 showed average sunspot numbers at 15.3 and average solar flux at 72.

Predicted solar flux is 78 and 77 on August 18-19, 76 on August 20-24, 72 on August 25, 68 on August 26-28, 70 on August 29, 72 on August 30 through September 8, 70 on September 9, 68 on September 10-24, 70 on September 25, and 72 on September 26 to October 1.

Predicted planetary A index is 24, 18, 16, 14 and 12 on August 18-22, 8 on August 23-24, 5 on August 25-29, then 12, 24, 18, and 14 on August 30 through September 2, 5 on September 3-7, 10 on September 8, 8 on September 9-10, then 5, 10, 20, 25, 15, 12, 10, 8 and 6 on September 11-19, 5 on September 20-25, and 12, 24, 18, and 14 on September 26-29, then 5 on September 30 and October 1.

"Geomagnetic activity forecast for the period August 18-24, 2017:

Quiet: Aug 22-24 Unsettled: Aug 20-22 Active: Aug 18-19 Minor storm: Aug 18

Geomagnetic activity summary: We expect an active minor storming episode within the next 24 hours. Expect active conditions August 18-19. Friday (August 18), the K-index may reach 5 (minor storming event). Saturday, August 19, we expect at most unsettled to active conditions.

The following two days August (20-21), we expect at most unsettled conditions with one isolated active event.

The rest of the forecast week (August 22-24), we expect quiet to unsettled conditions.

Tomas Bayer RWC Prague Institute of Geophysics of the Academy of Sciences of the Czech Republic, Prague Department of Geomagnetism Budkov observatory (BDV)'D

Solar eclipse mania:

http://bit.ly/2tG6njO

On Monday, don't miss the total solar eclipse and the related Solar Eclipse QSO Party: http://hamsci.org/seqp

For more information concerning radio propagation, see the ARRL Technical Information Service at http://arrl.org/propagation-of-rf-signals. For an explanation of 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/.

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 August 10-16, 2017 were 11, 11, 11, 11, 12, 21, and 30, with a mean of 15.3. 10.7 cm flux was 71, 69.8, 70.3, 68.2, 73, 74.2, and 77.3, with a mean of 72. Estimated planetary A indices were 5, 7, 11, 7, 5, 4, and 6, with a mean of 6.4. Estimated mid-latitude A indices were 7, 7, 12, 9, 5, 3, and 5, with a mean of 6.9. NN


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