domenica 23 aprile 2017

The K7RA Solar Update

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.


František 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.