 |
 |
|
|
|
|
|
|
||||||||||||||||||
|
|
|||||||||||||||||||
|
|
|||||||||||||||||||
|
|||||
|
|
 Previous: Hurricane Watch Net, WX4NHC Secure After Katrina Comes Ashore in Florida |  Next: Space QSO Provides Arizona Youngsters Something to Remember |
SEATTLE, WA, Aug 26, 2005--There was a huge geomagnetic storm at mid-week. On August 24 a large coronal mass ejection (CME) struck Earth, and the resulting geomagnetic storm stimulated bright aurora borealis visible as far south as Utah and Colorado.
The energy for all this emerged from fast-growing sunspot 798, which released two M-class solar flares on August 22. The planetary K index actually got up to 9 on August 24, and the planetary A index reached 110. The solar flux on the day of the flare rose nearly 60 points to 157.3--a big number for this part of the solar cycle.
During the same hour that one of the flares erupted, Ray Bass, W7YKN, of Sparks, Nevada, reported an HF radio blackout. He wrote, "Forty meters appeared to have died for about an hour. Only one local station about five miles away, W6FHZ, could be heard. Even WWV and WWVH were very weak here."
Solar activity should be low for the next few days, and geomagnetic conditions quiet. Predicted solar flux for Friday, August 26 through the following Monday is 95, 95, 90 and 90. Predicted planetary A index for those same days is 15, 8, 8 and 10.
Last week we mentioned some links to sites showing 6 meter E layer propagation over a number of years, all shown cumulatively by day of the year. This gives us some idea of what times of the year are best for this. Robert Mobile, K1SIX, of New Hampshire has a Web page with many more of these types of charts over many paths.
Another reader sent in an article from NASA about advances in space weather forecasting.
Finally, I'd like to note the passing of Phil Klass, who died August 9 at 85. Although I don't think Phil was ever a ham, he is credited with coining the term "avionics" as an aviation journalist. He was an editor of Aviation Week and Space Technology. I had the pleasure of his acquaintance, and subscribed to his newsletter for many years. The newsletter and his many wonderful books covered his research into aerial optical phenomena and how this and human error often were behind reports of objects in the air which otherwise could not be identified.
For more information concerning radio propagation and an explanation of the numbers used in this bulletin see the ARRL Technical Information Service Propagation page. An archive of past bulletins is on the ARRL Web site.
Sunspot numbers for August 18 through 24 were 42, 61, 74, 77, 85, 55 and 87, with a mean of 68.7. The 10.7 cm flux was 82.7, 93.1, 98.1, 98.5, 157.3, 112.3 and 98.6, with a mean of 105.8. Estimated planetary A indices were 16, 7, 5, 8, 12, 9 and 110, with a mean of 23.9. Estimated mid-latitude A indices were 9, 6, 2, 5, 7, 7 and 72, with a mean of 15.4.
Amateur
solar observer Tad Cook, K7RA, Seattle, Washington, provides this weekly report
on solar conditions and propagation. This report also is available via W1AW
every Friday, and an abbreviated version appears in The ARRL Letter. Readers may contact
the author via e-mail.
| Previous: Hurricane Watch Net, WX4NHC Secure After Katrina Comes Ashore in Florida | Next: Space QSO Provides Arizona Youngsters Something to Remember |
