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The K7RA Solar Update

03/03/2017

On March 2 at 2353 UTC the Australian Space Forecast Centre issued a geomagnetic disturbance warning for March 3.

“The Earth is currently under the influence of a high speed solar wind stream from a recurrent coronal hole. On 3 March geomagnetic activity is expected to reach active levels. Isolated minor storm periods are also possible.”

This reporting week (February 23 through March 1, 2017) sunspot and solar flux averages rose while geomagnetic indices remained about the same, compared to the previous seven days. Average daily sunspot numbers increased from 19.1 to 34.1, and average daily solar flux went from 78.5 to 81.3.

Average planetary A index barely changed from 11.3 to 13.1, and average mid-latitude A index (measured in Virginia) went from 9 to 8.7. The numbers went in opposite directions, but were each barely changed.

Predicted solar flux is 79 on March 3, 78 on March 4-5, 77 on March 6-7, 76 on March 8, 75 on March 9-14, then 74, 75, 77, 79, and 80 on March 15-19, 82 on March 20-23, 80 on March 24-25, 79 on March 26, 77 on March 27-28, 79 on March 29-31, 75 on April 1, 72 on April 2-3, 73 and 74 on April 4-5, 75 on April 6-10, and 74, 75 and 77 on April 11-13.

Predicted planetary A index is 22, 14, 10 and 8 on March 3-6, 5 on March 7-8, 8 on March 9, 5 on March 10-14 then 10, 20, 15, 10 and 8 on March 15-19, then 5, 8, 10, 15, and 8 on March 20-24, 5 on March 25-26, then 12, 25, 20, 15 and 8 on March 27-31, 5 on April 1-10, and 10, 20, 15 and 10 on April 11-14.

F.K. Janda, OK1HH sent this forecast:

“Geomagnetic activity forecast for the period March 3-28, 2017

Geomagnetic field will be:

Quiet on March 8-9, 12, 14, 26

Mostly quiet on March 10-11, 13, 15, 25

Quiet to unsettled March 7, 20-22, 24

Quiet to active on March 3-4, 6, 16, 18-19, 23, 27

Active to disturbed on March 5, 17, 28

Amplifications of the solar wind from coronal holes are expected on March 3-5, (6-8, 20-22,) 23-26.

Remark:  Parenthesis means lower probability of activity enhancement and/or lower reliability of prediction.”

 

We’ve been tracking a 3-month moving average of sunspot numbers for several years now. The peak was centered on February and March 2014, when the 3-month averages were 146.4 and 148.2. The average centered on the end of 2014 was 107.8, and a year later was 55.4. At the end of last year, the average was 21, and the average centered on January 2017 was 20.6. The cycle will probably reach minimum in 2020.

 

Jon Jones, N0JK, of Eastern Kansas sent this 10-meter update: “Good conditions continued on 10 meters this week.  The G2 class geomagnetic storm may have helped north - south paths. The TX5T Austral Islands DXpedition was loud on 28.027 MHz and in my log with one call at 2045z March 2. This on my mobile station. I saw aurora contacts spotted on 6 meters March 1 such as N8JX en64 to K9MU en44 at 2038z.”

 

Dr. Tamitha Skov issued this solar storm forecast video on February 23: http://bit.ly/2mNFO5g

 

 This weekend is the ARRL International DX SSB contest. See http://www.arrl.org/arrl-dx for details.

  

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 February 23 through March 1, 2017 were 18, 27, 25, 35, 40, 39, and 55, with a mean of 34.1. 10.7 cm flux was 83.3, 82.1, 80, 79, 82.2, 81.6, and 80.8, with a mean of 81.3. Estimated planetary A indices were 11, 20, 7, 2, 8, 8, and 36, with a mean of 13.1. Estimated mid-latitude A indices were 8, 15, 6, 0, 6, 5, and 21, with a mean of 8.7.

 

 



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