The past week saw increased solar activity, with average daily sunspot numbers rising from 5.3 to 19.6 and average daily solar flux from 69.8 to 74.5. We haven’t seen such strong activity since the beginning of last summer, when ARLP016 in 2018 reported average daily sunspot number at 22.6 and average daily solar flux at 75.3.
But sunspots only persisted from January 22 through January 30, and on January 31 they were gone.
Predicted solar flux is 72 on February 1-8, 69 on February 9-12, 72 on February 13-27, 70 on February 28 through March 3, 69 on March 4-11, and 72 on March 12-17. Predicted planetary A index is 18, 12, 10, 8, 12 and 8 on February 1-6, 5 on February 7-18, then 12, 20, 12 and 8 on February 19-22, 5 on February 23-26, then 8, 18, 10 and 8 on February 27 through March 2, and 5 on March 3-17.
At 2314 UTC on February 31 the Australian Space Forecast Centre issued a geomagnetic disturbance warning for the following day due to a high speed solar wind stream from a recurrent coronal hole. There is a chance of minor storm on Friday.
Geomagnetic activity forecast for the period February 1-27, 2019 from F.K. Janda, OK1HH.
Geomagnetic field will be:
Quiet on February 4-6, 8-9, 14, 24-26
Quiet to unsettled on February 7, 10, 17, 23, 27
Quiet to active on February 2-3, 13, 16, 18, 21-22
Unsettled to active on February 1, 11-12, 15, 20
Active to disturbed on February 19
Solar wind will intensify on February (1,) 2-3, (4, 7, 19,) 20-21, (22)
Parenthesis means lower probability of activity enhancement.
Report received from Jon Jones, N0JK, regarding FT8 activity on January 27: "Six-meter sporadic-E continued through the last week of January. Most of the paths favored the Gulf Coast states and Mexico. Winter sporadic-E tends to occur more frequently in these parts of North America.”
I received a -21 report (21 dB below noise) from W4TAA EL87 at 0035z: “I copied many decodes from XE2JS operating portable in rare grid DL78, but no luck getting a reply. I copied XE2JS working N8JX and KF8MY."
The latest video from Dr. Skov: https://www.youtube.com/watch?v=bDPdyxfNWdA
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 January 24 through 30, 2019 were 19, 27, 26, 22, 16, 15, and 12, with a mean of 19.6. 10.7 cm flux was 73.5, 73.1, 75.8, 75.1, 76.6, 75, and 72.4, with a mean of 74.5. Estimated planetary A indices were 19, 13, 7, 5, 1, 2, and 2, with a mean of 7. Estimated mid-latitude A indices were 13, 10, 5, 3, 0, 0, and 0, with a mean of 4.4.
