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ARRL Propagation Bulletin ARLP001 (2021)

SB PROP @ ARL $ARLP001
ARLP001 Propagation de K7RA

ZCZC AP01
QST de W1AW  
Propagation Forecast Bulletin 1  ARLP001
From Tad Cook, K7RA
Seattle, WA  January 2, 2021
To all radio amateurs 

SB PROP ARL ARLP001
ARLP001 Propagation de K7RA

Sunspot cycle 25 is progressing normally, and with the new year my
outlook is optimistic.  Solar minimum occurred only a bit more than
a year ago (December 2019) and now we see very few days with no
sunspots.

Average daily sunspot number over this past week was 27.1, and a
week ago the average was just 10.3.  Average daily solar flux rose
from 82.8 to 86.4.

Predicted solar flux over the next 30 days is 81 and 80 on January 1
and 2, 79 on January 3 and 4, 78 on January 5 to 8, then jumping to
84 on January 9 to 14, then 85, 86 and 87 on January 15 to 17, 88 on
January 18 to 28, 87 on January 29 and 86 on January 30.  It then
dips to 84 on February 1 to 10.

Predicted planetary A index is 5 on January 1 and 2, 8 and 5 on
January 3 and 4, 8 on January 5 to 7, 5 on January 8 to 17, 10 on
January 18 to 20, 8 on January 21, 5 on January 22 to 24, 10 on
January 25, and 5 on January 26 to 30.

Both the current sunspot groups (2794 and 2795) are about to slip
across the sun's western horizon.

When I check https://stereo.gsfc.nasa.gov/ for any possible coming
activity, I don't see anything obvious, but do not be surprised if
new activity appears soon, perhaps before mid-January along with the
predicted higher flux values.

From OK1HH:

"Geomagnetic activity forecast for the period January 1 to 26, 2021

Geomagnetic field will be 
Quiet on:  January 1, 3, 13 and 14 
Quiet to unsettled on:  January 2, 4, 8, 10, 12, 15 and 16, 21, 25
and 26 
Quiet to active on:  January 5 to 7, 9, 11, 17, 22 and 23 
Unsettled to active:  January 20, 24 
Active to disturbed:  January 18 and 19 

Solar wind will intensify on:  (January 1 to 3, 7 to 9, 19 and 20,)
21 and 22, (23, 25 and 26)

Remarks:
- Parenthesis means lower probability of activity enhancement.
- The predictability of changes is lower again, as there are
ambiguous and changing indications.

Wishing Happy New Year, positive thinking and negative tests.

F. K. Janda, OK1HH from Czech Propagation Interested Group compiling
these geomagnetic activity weekly forecasts since January 1978".

Ted Leaf, K6HI of Kona, Hawaii sent this, another optimistic report
on new cycle 25:

https://bit.ly/2XdqaUd

More on the NCAR prediction and the solar clock:

https://bit.ly/2MkHVyt

For more information concerning radio propagation, see
http://www.arrl.org/propagation and 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/.

Instructions for starting or ending email distribution of ARRL
bulletins are at http://arrl.org/bulletins .

Sunspot numbers for December 24 through 30, 2020 were 25, 30, 31,
26, 26, 26, and 26, with a mean of 27.1.  10.7 cm flux was 87.4,
87.7, 87.9, 87.8, 87.2, 84.2, and 82.8, with a mean of 86.4.
Estimated planetary A indices were 10, 5, 4, 6, 7, 7, and 9, with a
mean of 6.9.  Middle latitude A index was 7, 4, 3, 4, 6, 5, and 6,
with a mean of 5.
NNNN
/EX

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