SB PROP @ ARL $ARLP011
ARLP011 Propagation de K7RA

ZCZC AP11
QST de W1AW
Propagation Forecast Bulletin 11 ARLP011
From Tad Cook, K7RA
Seattle, WA March 17, 2017
To all radio amateurs

SB PROP ARL ARLP011
ARLP011 Propagation de K7RA

There haven't been any sunspots since March 3, other than March 5,
when one sunspot appeared for only one day. Also, solar flux values
have recently dipped below 70, for the first time since the other
side of this solar cycle.

Solar flux appears at 70 over the past week:

ftp://ftp.swpc.noaa.gov/pub/indices/DSD.txt

But this is an approximation. Resolved to 0.10, you can see that it
is dipping lower:

http://www.spaceweather.ca/solarflux/sx-5-flux-en.php

You want to look at the Observed Flux column.

Average daily sunspot number dropped from 14.1 to zero. Average
daily solar flux went from 74.3 to 70.3.

Average daily planetary A Index quieted from 20.9 to 8.1, while
average mid-latitude A index went from 15 to 6.4.

Predicted solar flux is 71 on March 17, 72 on March 18 to 20, 73 on
March 21, 74 on March 22 and 23, 76 on March 24 and 25, 74 on March
26 to 29, 72 on March 30 through April 3, and 70 on April 4 to 9.

Predicted planetary A index is 10 and 8 on March 17 and 18, 5 on
March 19 and 20, then 8, 10, 8 and 8 on March 21 to 24, 5 on March
25 to 27, then 35, 30, 20, 18, 15, 20 and 15 on March 28 through
April 3, 12 on April 4 and 5, 10 and 5 on April 6 and 7, then 8 on
April 8 to 13, 12 and 10 on April 14 and 15, 5 on April 16 and 17,
then 10, 15 and 8 on April 18 to 20, and 5 on April 21 to 23.

F. K. Janda, OK1HH of the Czech Propagation Interest Group sent us
this geomagnetic activity forecast for the period March 17 to April
12, 2017.

"Geomagnetic field will be:
Quiet on March 26, April 6 and 7, 9 and 10
Mostly quiet on March 21, April 5, 11
Quiet to unsettled March 22, (27,) April 1 and 2, 4
Quiet to active on March 17 to 20, (23 to 25,) 28, 31, April (8, 12)
Active to disturbed on March 29 and 30, (April 3)

Amplifications of the solar wind from coronal holes are expected on
March (18 to 22,) 23 to 27, April (3 to 8,) 14 to ?

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

Jon, N0JK wrote on March 16:

"There was a 6 meter Es opening last Friday March 10.

It was open from Florida to W1, W2, and W3 between 1600 and 1800z.

The W3DOG/b was spotted in Florida.

W3DOG/B 17/03/10 1717Z 50071.1 fm28el87 woof woof KD4ESV
W3DOG/B 17/03/10 1625Z 50071.0 FM28 589 IN FL EL87 WX4G

This is the second Es opening for the month of March, 2017."

Later, he wrote: "Potential for aurora March 28 and 29."

The National Science Foundation will abandon an historic solar
observatory in October, but New Mexico State University with take
charge and sustain it:

http://bit.ly/2mxqFV0

The vernal equinox is very close! The days and weeks before and
after are always a good time for HF propagation, and it is on March
20, this coming Monday.

A study on sunspot number re-calibration:

http://bit.ly/2ngm1yi

Also, here is a piece on solar cycles suggesting that the next cycle
may be larger than the current solar cycle:

http://www.leif.org/research/Predict...lar-Cycles.pdf

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 March 9 through 15, 2017 were 0, 0, 0, 0, 0, 0,
and 0, with a mean of 0. 10.7 cm flux was 71.2, 71, 70, 70.1, 70.3,
69.6, and 69.8, with a mean of 70.3. Estimated planetary A indices
were 15, 12, 6, 9, 3, 5, and 7, with a mean of 8.1. Estimated
mid-latitude A indices were 10, 14, 4, 7, 2, 3, and 5, with a mean
of 6.4.
NNNN
/EX