Sunspots reemerged for 8 days on March 5-12. Average daily sunspot numbers rose from 4.4 in last week’s bulletin to 9.9 this week (March 7-13). Average daily solar flux barely changed, from 70.6 to 70.9. Average planetary A index declined from 12.6 to 5.1, and average middle latitude A index from 9.7 to 3.9.
The vernal equinox will occur next Wednesday, March 20 when the southern and northern hemispheres will be bathed in equal amounts of solar radiation.
Predicted solar flux is 70 on March 15-17, 68 on March 18-22, 69 on March 23-28, 70 on March 29, 71 on March 30 through April 8, 70 on April 9, 69 on April 10-24, 70 on April 25 and 71 on April 26-28.
Predicted planetary A index is 12, 8 and 8 on March 15-17, 5 on March 18-19, 10 on March 20, 5 on March 21-25, then 12, 30, 28, 14 and 8 on March 26-30, 5 on March 31 through April 1, 8 on April 2-3, 5 on April 4-9, then 12, 10 and 8 on April 10-12, 5 on April 13-15, 10 on April 16, 5 on April 17-21, then 10, 26, 24, 12 and 8 on April 22-26 and 5 on April 27-28.
Geomagnetic activity forecast for the period March 15 to April 13, 2019 from F.K. Janda, OK1HH.
Geomagnetic field will be:
Quiet on March 22-24, 31, April 4-9. 13
Quiet to unsettled on March 16-18, 25, April 1-3, 11-12
Quiet to active on March 19-21, April 10
Unsettled to active on March 15, 26, 29-30
Active to disturbed on March 27-28
Solar wind will intensify on March (15,) 21-22, 25-28, April 1, (2, 5)
Parenthesis means lower probability of activity enhancement.
Australia’s Space Weather Services issued a geomagnetic disturbance warning at 0003 UTC on March 15. “Increased geomagnetic activity expected due to coronal hole high speed wind stream on March 15-16, 2019.
15 Mar: Unsettled to Active, possible Minor Storm periods for High latitudes
16 Mar: Quiet to Unsettled”
Jim DeYoung, N8OQ sent this interesting question on March 13: “I have been wondering about the fact the north magnetic pole has been shifting towards Russia significantly and therefore are there any expected resultant significant shifts in the auroral oval that would affect propagation to/from North America or to Asia?
“The reason I ask is I made probably my best contact of all time a few weeks ago during the CQ 160-Meter Phone Contest. I always run low power for that contest as a good test of my operating skills (ears), noise levels, rigs, and most importantly my antenna. I have used for many years a 93-meter horizontal loop antenna fed with about 24 meters of window line. The antenna is about 13 meters off the ground at its highest point. The ‘loop’ is more like a trapezoid, but actually it is what is called a scalene.
“For my station I had very good propagation conditions for the contest. Heard ZF9, ZF2, PJ4 (twice), TO4, C6, HQ9, OK7 and others I didn’t write down. Didn’t work any of them as one would expect with just 5 W output on SSB.
“However, on February 24 at 0417 UTC, I worked UA7K with on 1.838! It was his twilight sunrise on the north-east side of the Black Sea. Apparently, this was one of those fabled 160-meterm enhancements that occur at sunrise/sunset.
“I called once not expecting a thing. There was a pause on his end, and then I heard ‘N8OQ.’ I gave him a ‘Roger!’ and he replied with his CQ Zone (16). I responder with my report and state. He acknowledged and the contact when into the log. I received the confirmation via Logbook of The World a few days later!
“The contact was so easy, I soon began to think I must have been hearing things. Perhaps I didn’t copy his call sign correctly.
“I didn’t hear any of the big-gun station contacting him, but I heard at least one other run-of-the-mill US station work him for the few minutes I paused to monitor. When I checked again about 15 minutes later, he was gone, but I then heard a Czech station and a Lithuanian but didn’t get them. Both were also near their twilight sunrise line. My antenna and low noise floor allows me to hear these stations that few were calling. The UA7K clearly also had a very low noise floor, but this was apparently one of those super contest stations, the Russian Contest Club. My 5W was not enough to work any of the other good DX that was available. I was tempted several times to turn on the amp but resisted!
“Was this contact assisted by the auroral oval shifting away from the transatlantic path?”
Here is an interesting article about solar activity from Canada’s CBC: https://www.cbc.ca/news/technology/solar-activity-1.5049337
Thanks, David Moore, for sending this link concerning massive solar storms: https://www.sciencedaily.com/releases/2019/03/190311152744.htm
Here is the latest video from Dr. Tamitha Skov, WX6SWW: https://youtu.be/TSDfL9cwzEU
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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 March 7 through 13, 2019 were 14, 11, 11, 11, 11, 11, and 0, with a mean of 9.9. 10.7 cm flux was 70.9, 71.8, 70.7, 71.1, 70.4, 70.7, and 70.8, with a mean of 70.9. Estimated planetary A indices were 8, 5, 5, 4, 3, 7, and 4, with a mean of 5.1. Middle latitude A index was 5, 3, 4, 3, 3, 5, and 4, with a mean of 3.9.