[Propagation+Space Weather] The W1AW Weekly Propagation Report - 2018 Apr 27 17:21 UTC

[nw7us@sunspotwatch.com]

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The following is the weekly propagation bulletin from W1AW / ARRL (posting on 20180427 17:21 UTC):

QST de W1AW Propagation Forecast Bulletin 17 ARLP017 >From Tad Cook, K7RA Seattle, WA April 27, 2018 To all radio amateurs

SB PROP ARL ARLP017 ARLP017 Propagation de K7RA

Solar activity increased over the past week, with average daily sunspot numbers up from 5.4 to 20 and average daily solar flux rallying from 69.9 to 73.4. The previous week saw four days with no sunspots, and the recent week had sunspots on every day. New sunspot groups emerged on April 19 and 21.

Predicted solar flux is 69 on April 27-29, 68 on April 30 through May 3, 70 on May 4-16, 75 on May 17-29, 70 on May 30 through June 10.

Predicted planetary A index is 12 on April 27, 5 on April 28 through May 5, then 10, 15, 12, 10 and 8 on May 6-10, 5 on May 11-16, then 42, 12 and 8 on May 17-19, 5 on May 20-22, then 8 and 12 on May 23-24, 5 on May 25 through June 1, then 10, 15, 12, 10 and 8 on June 2-6, then 5 on June 7-10.

Geomagnetic activity forecast for the period April 27 to May 22, 2018 from F.K. Janda, OK1HH of the Czech Propagation Interest Group.

'Geomagnetic field will be: Quiet on April 30 Mostly quiet on April 28, May 3, 14, 16, 21-22 Quiet to unsettled on April 27, 29, May 1, 4, 8, 11-13, 19-20 Quiet to active on May 2, 5, 9-10, 15, (18) Active to disturbed on May 6-7, 17

'Solar wind will intensify on April (27-29), May (2,) 5-7, (8-11,) 17-18, (19-20).

'Remarks: - Parenthesis means lower probability of activity enhancement. - With regard to ongoing changes, current forecasts are less reliable again.'

Interesting videos with general information on sunspots and solar flares:

http://www.thesuntoday.org/the-sun/solar-activity/

>From the same source, multiple detailed images per day of the Sun viewed at different wavelengths:

http://www.thesuntoday.org/the-sun-now/

Dr. Tamitha Skov will probably release a new space weather video after this bulletin is sent to ARRL HQ for distribution. This is probably a good place to check for her latest report:

https://www.youtube.com/user/SpWxfx

If you would like to make a comment or have a tip for our readers, email the author at, k7ra@arrl.net .

For more information concerning radio propagation, see the ARRL Technical Information Service web page 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 bat http://arrl.org/bulletins.

Sunspot numbers for April 19 through 25, 2018 were 14, 14, 34, 20, 22, 19, and 17, with a mean of 20. 10.7 cm flux was 70.8, 73, 76.8, 75.7, 73.9, 72.9, and 70.8, with a mean of 73.4. Estimated planetary A indices were 3, 47, 12, 5, 6, 5, and 5, with a mean of 11.9. Estimated mid-latitude A indices were 2, 29, 10, 5, 6, 4, and 4, with a mean of 8.6.

Check out the stunning view of our Sun in action, as seen during the last five years with the Solar Dynamics Observatory (SDO): https://www.youtube.com/watch?v=zXN-MdoGM9g

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NOTICE: When you buy this (or any item after starting with this link), you are helping us keep our SunSpotWatch.com and other resources "on the air" (up and running!). In other words, you are helping the entire community. So, check out this book:

Here is the link to Amazon: http://g.nw7us.us/fbssw-aSWSC

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Visit our live space weather and radio propagation web site, at: http://SunSpotWatch.com

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