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The K7RA Solar Update

11/17/2017

Thirteen days of zero sunspots ended on Tuesday, with sunspot numbers of 14, 14, and 15 on Tuesday through Thursday.

In this week’s bulletin average daily sunspot numbers increased from 0 to 4, while average daily solar flux decreased slightly from 70.8 to 70.3. Average planetary A index decreased from 15.6 to 12.3, and average mid-latitude A index declined from 12.4 to 8.6.

Predicted solar flux is 74 on November 17-24, 75 on November 25-27, then 73, 72 and 71 on November 28-30, 70 on December 1-2, 69 on December 3-4, 68 on December 5-7, 69 on December 8-9, 70 on December 10, 73 on December 11-16, 75 on December 17-24, then 73, 72 and 71 on December 25-27, 70 on December 28-29, and 69 on December 30-31.

Predicted planetary A index is 14, 10 and 15 on November 17-19, 20 on November 20-21, then 18 and 10 on November 22-23, 5 on November 24-28, then 8 and 10 on November 29-30, 5 on December 1-3, then 35, 40, 28, 20 and 10 on December 4-8, 5 on December 9-10, then 15, 18, 12, 15, 12 and 8 on December 11-16, 20 on December 17-19, 8 on December 20, 5 on December 21-25, 8 and 10 on December 26-27, 5 on December 28-30 and on December 31 it jumps to 35, indicating disturbed conditions.

Geomagnetic activity forecast for the period November 17 to December 13, 2017 from F.K. Janda, OK1HH of the Czech Propagation Interested Group compiling this geomagnetic activity weekly forecast since 1978.

Geomagnetic field will be:
Quiet on November 24-28, December 2, 9
Mostly quiet on November 19, 23, 29, December 8
Quiet to unsettled on November 18, December 1, 3, 11-12
Quiet to active on November 17, 30, December 4, 7, 12-13
Active to disturbed on November 20-22, December 5-6

Amplifications of the solar wind from coronal holes are expected on November (17-19,), 20-24, (29-30,) and on December (1-5,) 5-7, 9-12.

Remarks:
- Parenthesis means lower probability of activity enhancement.
- Current forecasts still remains less reliable ...


ARRL SSB Sweepstakes contest is this weekend. Rules can be found at http://www.arrl.org/sweepstakes

Out of Japan, this study confirms that during sunspot cycle minimums, solar activity is consistent from cycle to cycle, but not at solar cycle peaks. https://www.eurekalert.org/pub_releases/2017-11/nion-sms111617.php


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 November 9 through 15, 2017 were 0, 0, 0, 0, 0, 14, and 14, with a mean of 4. 10.7 cm flux was 65.8, 68.6, 67.3, 69.4, 72.1, 74.4, and 74.2, with a mean of 70.3. Estimated planetary A indices were 20, 21, 8, 6, 6, 11, and 14, with a mean of 12.3. Estimated mid-latitude A indices were 11, 13, 7, 4, 6, 8, and 11, with a mean of 8.6.

 



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