SB PROP @ ARL $ARLP016
ARLP016 Propagation de K7RA

ZCZC AP16
QST de W1AW
Propagation Forecast Bulletin 16 ARLP016

From Tad Cook, K7RA

Seattle, WA April 21, 2017
To all radio amateurs

SB PROP ARL ARLP016
ARLP016 Propagation de K7RA

This just in from the Australian Space Forecast Centre at 2349 UTC on April 20,
2017:

Recurrent coronal hole is expected to be geoeffective.

INCREASED GEOMAGNETIC ACTIVITY EXPECTED DUE TO CORONAL HOLE HIGH SPEED WIND STREAM FOR 23 APRIL 2017

GEOMAGNETIC ACTIVITY FORECAST 23 Apr: Active to Minor Storm

Spaceweather.com reported old sunspot AR2644 returned after a 2-week trip around the Sun, and exploded on April 18. The resulting CME should miss Earth, but as this active region moves into a geo-effective position we could see some
geomagnetic disturbance in the next few days.

Average daily sunspot numbers declined from 16.6 last week to 8.6 in this reporting week, April 13-19. Average daily solar flux increased from 73.8 to 76.5.

Geomagnetic indicators were lower this week. Average planetary A index declined
from 10.6 to 8, while average mid-latitude A index was 6.3, down from 9.3 the previous seven days.

Predicted solar flux is 85 on April 21-27, 80 on April 28 to May 1, 75 on May 2-13, 83 and 88 on May 14-15, 90 on May 16-18, 85 on May 19-24, 80 on May 25-28, and 75 on May 29 through June 4.

Predicted planetary A index is 12, 8, 40 and 30 on April 21-24, 20 on April 25-27, then 15, 10, 5 and 20 on April 28 through May 1, 10 on May 2-4, 15 on May 5-6, then 5 and 8 on May 7-8, 5 on May 9-13, 20 on May 14, 15 on May 15-16,
10 on May 17, 5 on May 18-19, then 35, 25, 18, 20 and 25 on May 20-24, then 12,
8, 5 and 18 on May 25-28, and 10 on May 29 through June 4.

Franz K. Janda, OK1HH of the Czech Propagation Interest Group sent us his geomagnetic activity forecast for the period April 21-May 17, 2017. 2017 marks the 40th year Franz has been writing these
bulletins.

"Geomagnetic field will be:
Quiet on April 22, 30, May 13
Mostly quiet on April 29, May 8
Quiet to unsettled April 21, May 3, 7, 10-12, 14-15
Quiet to active on April 24-25, 27-28, May 1-2, 4-5, 8, 16
Active to disturbed on April 23, 26, May 6, 17

"Increasing solar wind from coronal holes are expected on April (21-22,) 23-28,
May (1-4,) 7-8, (9-11,) and 18-19.

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


And from another Czech resource, a near term geo-forecast from Thomas Bayer of the Budkov Observatory:

"Geomagnetic activity forecast for the period April 21-April 27, 2017:

"Quiet: Apr 21-22
Unsettled: Apr 22-23, 25-27
Active: Apr 23-25
Minor storm: possible Apr 23-24
Major storm: 0
Severe storm: 0

"Geomagnetic activity summary:

"Until the nearest Saturday, April 22, we expect quiet to unsettled conditions.
Between Sunday, April 23, and Monday, April 24, we expect active episode arrival caused by present equatorial coronal hole. During these two days, storming effect is possible.

"The following days, we expect at most unsettled conditions only with isolated active episodes. The last day of the forecast period, we expect geomagnetic activity decrease to quiet to unsettled level.

"Tomas Bayer RWC Prague Institute of Geophysics of the ASCR, Prague Department of Geomagnetism Budkov observatory (BDV)."


According to this, we are due for more low solar activity, but there is a chance of C-class and M-class flares:

http://www.spaceref.com/news/viewsr.html?pid=50058

Also from Spaceref, tomorrow a March for Science in Washington, DC:

http://spaceref.com/calendar/calendar.html?pid=9388


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 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 April 13 through 19, 2017 were 12, 11, 11, 0, 0, 12, and 14, with a mean of 8.6. 10.7 cm flux was 73.5, 72.9, 73, 74.5, 75.2, 85.6, and 80.9, with a mean of 76.5. Estimated planetary A indices were 5, 14, 7, 4, 4, 7, and 15, with a mean of 8. Estimated mid-latitude A indices were 4, 10, 5, 4,
3, 6, and 12, with a mean of 6.3.

NNNN
/EX

)\/(ark

Always Mount a Scratch Monkey
Do you manage your own servers? If you are not running an IDS/IPS yer doin' it wrong...
... Call it a hunch. - Quasimodo
---
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SB PROP @ ARL $ARLP016
ARLP016 Propagation de K7RA

ZCZC AP16
QST de W1AW
Propagation Forecast Bulletin 16 ARLP016

From Tad Cook, K7RA

Seattle, WA April 20, 2018
To all radio amateurs

SB PROP ARL ARLP016
ARLP016 Propagation de K7RA

At 0631 UTC on April 20 the Australian Space Forecast Centre issued a Geomagnetic Disturbance Warning.

"Earth is currently under the influence of a high speed stream from a negative polarity equatorial coronal hole. Geomagnetic activity at Quiet to Active levels is expected and at times may reach up to Minor Storm levels if there are
notable southward Bz periods.

"INCREASED GEOMAGNETIC ACTIVITY EXPECTED DUE TO CORONAL HOLE HIGH SPEED WIND STREAM FROM 20-21 APRIL 2018

"GEOMAGNETIC ACTIVITY FORECAST
20 Apr: Quiet to Active
21 Apr: Quiet to Active"


This link to Space Weather Live explains the reference to "southward Bz periods" above:

https://bit.ly/1S6H68D


Average daily sunspot number over the recent reporting week (April 12-18) rose from 0 to 5.4. Of course, any non-zero sunspot number lower than 11 is imaginary, because of the arcane method used for calculating sunspot numbers.

Every sunspot group counts for 10 points, and each sunspot within that group counts as one point. So one sunspot in one group yields a sunspot number of 11.
Three sunspots in two groups yields a daily sunspot number of 23. The last time
we saw a sunspot number greater than 22 was February 9-12 when the numbers were
23, 35, 24 and 26.

So an average daily sunspot number lower than 11 must include at least one zero-sunspot day. In the past reporting week, only three days had any sunspots.

Average daily solar flux rose from 67.7 to 69.9. Average daily planetary A index declined from 9.4 to 6.1, while average mid-latitude A index went from 8.1 to 5.6.

Predicted solar flux for the next 45 days is 72 on April 20-26, 71 on April 27,
69 on April 28 through May 5, 70 on May 6-12, 72 on May 13-19, 69 on May 20 through June 1, and 70 on June 2-3.

Predicted planetary A index is 15, 12 and 8 on April 20-22, 5 on April 23-25, 8
on April 26, 5 on April 27 through May 5, 10 on May 6, 15 on May 7-8, 10 on May
9-10, 5 on May 11-15, 12 and 10 on May 16-17, 5 on May 18 through June 1, then 10 and 12 on June 2-3.


F.K. Janda, OK1HH of the Czech Propagation Interest Group brings us his weekly geomagnetic activity forecast for the period April 20 to May 15, 2018.

"Geomagnetic field will be:
Quiet on April 24-25, 27-28, May 13-14
Mostly quiet on April 22-23, May 15
Quiet to unsettled on April 26, 29-30, May 1, 3-5, 9, 12
Quiet to active on April (21,) May 2, 7-8, 10-11
Active to disturbed on April (20,) May 6

"Solar wind will intensify on April (24)-25, May (2-3,) 5-6, (7-11)

"Remark:
- Parenthesis means lower probability of activity enhancement.
- With regard to ongoing changes, current forecasts are less
reliable again."

From SolarHam, which presents a weekly Monday observation:

https://www.youtube.com/watch?v=TW8EXYUPcz4


Dr. Skov reports from a scientific conference in Switzerland this
week:

https://youtu.be/9MEEzyxJ_cw


"On the Hunt for Stealthy Solar Storms

"Dear Tad,

"I'm writing you while sitting in the ISSI meeting room in Bern, Switzerland listening to twelve fascinating scientists argue about solar observations. The discussion is quite lively as we learn how we can work together to detect and forecast an invisible kind of solar storm. These storms are called 'stealth CMEs' and they used to be rare events. But with our quiet Sun, all that is changing. There is a very good chance that these near invisible events will continue to cause surprise storms at Earth over the next decade, disrupting amateur radio, GPS, and causing issues for power grids with little or no warning of their impact. Solving this significant problem is exactly why we have assembled here in Bern.

"This week I highlight this amazing team of solar and space physicists, who are
helping shape the future of Space Weather prediction. The forecast is shot in my hotel room so it has more of a 'live' feel than my usual studio productions.
Hopefully, it not only gives you a look into the new activity our Sun brings this week, but also gives you a glimpse into the important part of my world that is Space Weather research.

"Cheers, Tamitha"

http://www.solarham.net/


A look at the STEREO image on Friday morning shows an active region
just beyond the horizon:

https://stereo.gsfc.nasa.gov/


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 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 April 12 through 18, 2018 were 13, 14, 11, 0, 0, 0, and 0, with a mean of 5.4. 10.7 cm flux was 70, 69.7, 69.5, 70.6, 69.2, 69.3, and 70.8, with a mean of 69.9. Estimated planetary A indices were 9, 9, 6, 6, 3, 4,
and 6, with a mean of 6.1. Estimated mid-latitude A indices were 8, 8, 6, 5, 3,
3, and 6, with a mean of 5.6.

NNNN
/EX

)\/(ark

Always Mount a Scratch Monkey
Do you manage your own servers? If you are not running an IDS/IPS yer doin' it wrong...
... Things always get a little more complicated, don't they, sir?
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* Origin: (1:3634/12.73)