Following a good two-week run, sunspots disappeared after April 20. The average daily sunspot numbers for the recent reporting week were 8.1, down from 14 reported in last week’s bulletin, and average daily solar flux was 70.6, down from 76.4. Daily planetary and mid-latitude A index were nearly the same this week, with the average planetary A index at 4.7 and middle latitude A index at 4.6.

Predicted solar flux for the next 45 days is 69 on April 26-30, then 70 on May 1-2, 72 on May 3, 76 on May 4-5, 77 on May 6, 78 on May 7-16, 76 and 72 on May 17-18, 69 on May 19-29, then 72, 76, 76 and 77 on May 30 through June 2, and 78 on June 3-9.

Predicted planetary A index is 10, 5 and 10 on April 26-28, 5 on April 29 through May 1, then 15, 10, 5, 10, 12 and 14 on May 2-7, 8 on May 8-10, 5 on May 11-19, 8 on May 20-22, then 5, 12, 8 and 5 on May 23-26, 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 7-9.

Geomagnetic activity forecast for the period April 26-May 20, 2019 from F.K. Janda, OK1HH.

Geomagnetic field will be:

Quiet on April 28, May 11, 13-14, 16, 18-19

Quiet to unsettled on April 26, May 3-4, 8-9, 12, 15, 17

Quiet to active on April 30, May 1-2, 10, 20

Unsettled to active on April 27, 29, May 5-7

Solar wind will intensify on May 3-5, 9-13, 15, (20).

Parenthesis means lower probability of activity enhancement.

On April 22, Tom Scott, N5GIT, in San Antonio wrote: “Just bagged my first 2-meter SSB contact with Florida! I was only running 100 W to a K5VH 3-ring halo antenna at 28 feet tied to a second story balcony.”

Here is Dr. Skov’s latest video: https://youtu.be/W9Fp-O3Ddlo

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.

Instructions for starting or ending email distribution of ARRL bulletins are at http://arrl.org/bulletins.

Sunspot numbers for April 18 through 24, 2019 were 23, 23, 11, 0, 0, 0, and 0, with a mean of 8.1. 10.7 cm flux was 74.6, 72.7, 69.9, 69.3, 69.4, 68.8, and 69.3, with a mean of 70.6. Estimated planetary A indices were 2, 4, 4, 4, 4, 8, and 7, with a mean of 4.7. Middle latitude A index was 2, 4, 4, 4, 4, 8, and 6, with a mean of 4.6.