SB PROP @ ARL $ARLP037
ARLP037 Propagation de K7RA

ZCZC AP37
QST de W1AW
Propagation Forecast Bulletin 37  ARLP037
> From Tad Cook, K7RA
Seattle, WA  September 9, 2016
To all radio amateurs

SB PROP ARL ARLP037
ARLP037 Propagation de K7RA

Compared to the last reporting week, this week (September 1-7) average daily
sunspot numbers were down, solar flux increased, and geomagnetic indices were
much more active.

Average daily sunspot number declined from 60.1 to 46.4, while average solar
flux went from 87.9 to 95.1. Average planetary A index increased from 8 to
26.6, while average mid-latitude A index rose from 6.9 to 18.1.

The daily planetary A index on September 1-4 was 36, 39, 40 and 28. It looks
like an echo of the solar wind which caused this activity is expected on
September 28 through October 1, when the predicted planetary A index is 35,
38, 40 and 25.

Predicted solar flux is 95 on September 9-10, then 92, 90, and 85 on September
11-13, 80 on September 14-16, 108 on September 17-19, then 110, 105 and 110 on
September 20-22, 112 on September 23-24, 108 on September 25, 105 on September
26-27, 100 on September 28, 95 on September 29 through October 1, 98 on
October 2-4, 95 on October 5-6, 90 on October 7-8, 95 on October 9, 100 on
October 10-11, 105 on October 12, and 108 on October 13-16. After October 16
flux values meander from 105 to 112.

On September 5 predicted solar flux values for September 13 to October 21 got
a big boost, a predicted increase ranging from 18-30 points from the September
4 prediction.

Predicted planetary A index is 15 on September 9, 8 on September 10-11, 10 on
September 12, 8 on September 13-15, 5 on September 15-16, then 8, 5, 15, 12
and 8 on September 17-21, 5 on September 22-25, then 12, 8, 35, 38 and 40 on
September 26-30, then 25, 20 and 12 on October 1-3, 10 on October 4-5, 5 on
October 6-9, then 10, 8, 5, 5, 8, 5, 15, 12 and 8 on October 10-18, and 5 on
October 19 and beyond.

Petr Kolman, OK1MGW of the Czech Propagation Interest Group predicts the
geomagnetic field will be:

Quiet on September 23-24
Mostly quiet on September 9-11, 14-16, 18, 22, October 5
Quiet to unsettled on September 12, 17, 21, 25, 27, October 3-4
Quiet to active on September 13, 19-20, 26, 28-30, October 1-2
Active to disturbed on September (29-30)

Increased solar wind from coronal holes is expected on September 12-13, 17,
19-21, 25-26, 28-30, October 1-2

Remarks: - Parenthesis means lower probability of activity enhancement.

Propagation expert Carl Luetzelschwab, K9LA gave a talk (via the Internet) to
the World Wide Radio Operator's Foundation on August 23, as reported this week
on the ARRL web site:

http://bit.ly/2c3yMbZ

Also note the link in the article to Carl's presentation to the club, "Solar
Topics - Where We're Headed." See/hear it at http://bit.ly/2ceGTiE .

Carl notes that some forecasters of space weather have predicted smaller solar
cycles in the future. But personally, I would not be so sure (I'm always
searching for something to be positive about, when it relates to future solar
activity).


Check out this presentation by Douglas Biesecker, Chair of the Solar Cycle 24
Prediction Panel, http://bit.ly/2cz5zkD, which does not predict low solar
activity extending decades into the future.

Note also that Carl predicts a future Cycle 25 at least as strong as Cycle 24.

Carl also mentioned a number I had not heard before. He notes that many solar
cycles in the past have been equivalent to Cycle 19, the biggest sunspot cycle
experienced by anyone still alive today. He projects back over the past 11,000
years, and with the number he gives, the next grand maximum after Cycle 19 in
the late 1950s might be around year 2537 AD. Note that Carl did not predict
this. I am just trying to extrapolate from the numbers he mentioned, to get
some very rough idea of how uncommon Cycle 19 was.

His numbers show that over the past 11,000 years, 19 notable grand maximums -
including Cycle 19 and the cycles around it - and 27 notable grand minimums
were recorded. "We're likely to have more of both grand maximums and grand
minimums in the future," he predicted. But arithmetically estimated from 19
maximums in 11,000 years, that puts the next big one (after Cycle 19) at 521
years from now, maybe in Cycle 71.


Finally, we received a note from Dick Ferry, K2KA of Westford, Massachusetts
concerning 6-meter auroral propagation on September 3:

"Some notes of last night's brief AU opening.

"Got up at 1230am (0430Z) Sep 3, saw AU activity on 6M.

"I heard KL7NO on 50.1056 MHz.  He was very weak, barely copiable but I did
hear him. Didn't call him as he was only audible for a few seconds.

"That would have been awesome!

"Did call CQ for about 5 min.

"K0KP/B, N8PUM/B and VE4VHF/B were loud. But no humans on the band. The
beacons were gone in about 10 min.

"73, Dick K2KA (formerly AB1A)."

Thanks Dick!


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 web page at, http://arrl.org/propagation-of-rf-signals.
For an explanation of the numbers used in this bulletin, see htt
://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 September 1 through 7 were 66, 50, 46, 59, 22, 32, and 50,
with a mean of 46.4. 10.7 cm flux was 95.2, 94.6, 99, 97.4, 93.8, 92.4, and
93, with a mean of 95.1. Estimated planetary A indices were 36, 39, 40, 28,
17, 14, and 12, with a mean of 26.6. Estimated mid-latitude A indices were 29,
24, 21, 20, 13, 12, and 8, with a mean of 18.1.

NNNN
/EX

)\/(ark

Always Mount a Scratch Monkey

... Never order chicken-fried steak in a place that doesn't have a jukebox.
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