No sunspots were visible over the recent reporting week (April 25 through May 1), and so the average daily sunspot number dropped to zero after 8.1 during the previous seven days. Average daily solar flux declined from 70.6 to 67.5. Geomagnetic indicators were quiet, with average planetary A index at 5.9, up from 4.7 in the previous week.

Predicted solar flux is 72 on May 3-5, 75 on May 6-9, 78 on May 10-16, then 76, 72 and 70 on May 17-19, 69 on May 20-21, 68 on May 22, 67 on May 23 through June 2, 70 and 75 on June 3-4, 78 on June 5-12, then 76, 72, 70 and 69 on June 13-16.

Predicted planetary A index is 5 on May 4-9, 8 on May 10, 5 on May 11-19, 8 on May 20, 5 on May 21-26, then 10, 14, 12, 8 and 5 on May 27-31, then 10, 12 and 14 on June 1-3, 8 on June 4-6, and 5 on June 7-15, then 8 on June 16.

Interesting article in the New Yorker about aurora borealis tourism: https://bit.ly/2UvvVbN

Here is a video from Dr Skov, WX6SWW: https://youtu.be/W9Fp-O3Ddlo

Geomagnetic activity forecast for the period May 3-30, 2019 from F.K. Janda, OK1HH.

Geomagnetic field will be:
quiet on May 15, 19, 22-23
quiet to unsettled on May 6, 8-16, 18, 24-27
quiet to active on May 3-5, 17, 21, 28
unsettled to active on May 7, 20, 29-30
No Active to Disturbed conditions are forecast.

Solar wind will intensify on May 3-4, 9-13, 15, (20,) 22-23, 30

Parenthesis means lower probability of activity enhancement.

Thanks to M0VNG and others for the tip to this article on moving geomagnetism: https://bit.ly/2IWoqJA

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 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.

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Sunspot numbers for April 25 through May 1, 2019 were 0, 0, 0, 0, 0, 0, and 0, with a mean of 0. 10.7 cm flux was 67.5, 67.2, 66.9, 67.9, 66.9, 68.5, and 67.6, with a mean of 67.5. Estimated planetary A indices were 5, 4, 6, 5, 5, 5, and 11, with a mean of 5.9. Middle latitude A index was 4, 2, 5, 4, 6, 4, and 8, with a mean of 4.7.