ARRL

Secure Site Login

News

The K7RA Solar Update

02/24/2017

At 0124 UTC on February 22 Australian Space Weather Services issued a geomagnetic disturbance warning for February 22-24.

“The effect of a high speed solar wind stream from a recurrent coronal hole is expected to raise geomagnetic activity to active levels from 22 to 24 February with the possibility of minor storm periods on 23 and 24 February.

Increased geomagnetic activity expected due to coronal hole high speed wind stream from 23-24 February 2017.

Geomagnetic Activity Forecast

23 Feb:  Unsettled to Active, isolated Minor Storm periods possible

24 Feb:  Unsettled to Active”

Spaceweather.com on February 22 issued a Solar Wind Advisory: “Earth is about to enter a stream of solar wind flowing from a hole in the sun's atmosphere. NOAA forecasters estimate a 60% chance of polar geomagnetic storms on Feb. 23rd as the solar wind speed quickens to 550 km/s or more. Arctic sky watchers should be alert for auroras on Thursday and Friday nights. See updates and sightings at Spaceweather.com.”

Over the past week, February 16-22, average daily sunspot number compared to the previous seven days increased from 17.6 to 19.1, while average solar flux increased from 75.1 to 78.5.

Geomagnetic indicators were slightly higher, with average planetary A index increasing from 4.7 to 11.3, and average mid-latitude A index changing from 2.9 to 9.

Predicted solar flux (on February 22) is 84 on February 23-24, 83 on February 25, 82 on February 26 through March 1, 78 on March 2, 73 on March 3-4, 72 on March 5-7, 73 and 74 on March 8-9, 75 on March 10-14, then 74, 75, 77 and 79 on March 15-18, 82 on March 19-24, then 80, 78 and 76 on March 25-27, 75 on March 28-29, 73 on March 30-31, and 72 on April 1-3.

Predicted planetary A index is 18 and 12 on February 23-24, 8 on February 25-26, then 16, 24 and 20 on February 27 through March 1, 15 on March 2-5, 8 on March 6, 5 on March 7-14, then 10, 20, 15, 10 and 12 on March 15-19, 10 on March 20-21, then 12, 15, 20 and 18 on March 22-25, then 8, 30, 25 and 20 on March 26-29.

Geomagnetic predictions are included as usual this week from F.K. Janda, OK1HH, but first is a shorter term forecast from Thomas Bayer of the Department of Geomagnetism at the Budkov Observatory.

Geomagnetic activity forecast for the period February 24-March 2, 2017

Quiet: episodically Feb 25-26

Unsettled: Feb 25-Mar 2

Active: Feb 24-25, 28, Mar 1

Minor storm:  possible Feb 24, 28

Major storm: 0

Severe storm: 0

Geomagnetic activity summary:

We expect unsettled conditions during the next week. Tomorrow, Friday, February 24, we expect an active episode, unlikely minor storm event. The other active episode is probable at February 28-March 1. The activity is probable at active/minor storm again.

The other days, we expect at most unsettled conditions. During the coming weekend, the activity can briefly decrease to quiet level, then, we expect at most unsettled conditions till the active episode mentioned above.

Tomas Bayer

RWC Prague

Institute of Geophysics of the ASCR, Prague

Department of Geomagnetism

Budkov observatory (BDV)

 

Geomagnetic activity forecast for the period February 24-March 22, 2017

Geomagnetic field will be:

Quiet on March 7-8, 11-12, 15

Mostly quiet on February 25-26, March 6, 14

Quiet to unsettled February 24, March 9-10, 13, (21-22)

Quiet to active on February 27, March 3-5, 16, 19-20

Active to disturbed on February 28, March 1-2, 17-18

Amplifications of the solar wind from coronal holes are expected on February 27-28, March 3-5, (6-8)

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

F.K. Janda, OK1HH

 

Jon Jones, N0JK, (editor of QST’s “The World Above 50 MHz” column) sent some notes on last weekend’s ARRL International CW DX Contest. (The Phone contest weekend will be on March 4-5, 2017): “The 10-meter band was like day and night between Saturday and Sunday of the ARRL DX CW contest.

“I operated fixed mobile single band on 10 with a full size 1/4 wave whip both days. Saturday was nice and sunny, but almost a dead band. I found PJ2T and PJ4X, both weak with QSB, and worked them. I called XR2K for over an hour with no luck. That was it. Is this how 10 meters will be at solar minimum?

“Ten meters was so much better Sunday. It was a flashback to how 10 was in the 2016 ARRL DX CW contest when the solar flux was around 100. I set up, turned on the radio and 100-W PY2NY was blasting in on 28.034 MHz.

“Chile, Uruguay and Brazil were strong for hours. Caribbean and Central American contest stations were up and down the band. Not bad for a solar flux of just 77. 

“I worked PJ7AAA at 1856Z and he was running just an Elecraft K3 transceiver and a Buddipole antenna. I put XR2K in the log with one call at 1940Z and picked up the KH6LC multi-op at 1955 Z for Hawaii on what sounded like side-scatter. They were about 559, but hearing well. KH6LC said in their 3830 post: ‘We watched 10 meters all weekend and it paid off Sunday morning when it opened for us at 1715Z.’ KH6LC made 488 North American contacts on 10.

“Ten meters folded for me around 2200Z. I dropped down to 15 and gave a very loud KH6LC (operator Fred, K6IJ) a contact and then worked A31MM. Fred made 1690 contest contacts from KH6LC on 15 meters. The solar flux was the same: 77 on both Saturday and Sunday. Why was 10 so much better on Sunday?”

 

According to the ARRL DX Bulletin, the CQ 160 meter SSB Contest is this weekend. Check http://www.cq160.com/rules.htm for rules.

 

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 February 16 through 22, 2017 were 23, 14, 13, 23, 25, 19, and 17, with a mean of 19.1. 10.7 cm flux was 74, 74.6, 76.6, 78.1, 80.7, 82.5, and 83.2, with a mean of 78.5. Estimated planetary A indices were 9, 20, 16, 10, 10, 4, and 10, with a mean of 11.3. Estimated mid-latitude A indices were 7, 16, 11, 9, 8, 4, and 8, with a mean of 9.

 

 



Back