[CQ-Contest] X7.1 Flare Peak 0659 / Proton Storm

nw7us at hfradio.org nw7us at hfradio.org
Thu Jan 20 09:37:12 EST 2005

NW7US Propagation Bulletin
20 January 2005 - 1430 UTC

At the time of this bulletin, active sunspot region 10720 (720) continues  
its flaring activity.  Since the X3.8 flare of 17-I-2005 that peaked at  
0954 UTC, we've seen three M-class flares (peaks at 1134 and 1549 UTC,  
18-I-2005 and 1539 UTC, 19-I-2005), and two X-class flares (peaks at 0824  
UTC, 19-I-2005, and 0659 UTC, 20-I-2005).  The most recent X-class, the  
X7.1 level flare, has created a very strong proton storm.  This proton  
storm has caused the saturation of sensors aboard various satellites which  
are used to monitor the solar wind speed, causing them to become  

Region 720 is near the edge of the solar disk, about to rotate off the  
visual side.  The expolsion of coronal material will not be directed  
toward Earth in any significant way.  However, we are expecting the  
arrival soon of the coronal mass ejection from the X1.3 flare from  
yesterday.  This will be a glancing blow, but since it is riding a solar  
wind that is already somewhat elevated from the currently geo-effective  
coronal hole, we expect perhaps up to minor storm level geomagnetic  
activity.  With the inability to monitor the solar wind, it will not be  
clear when and if the CME from the X1.3 flare hits.

HF propagation today will be fair to good on low- and mid-latitude paths,  
until sometime after the CME hits.  HF propagation via the polar routes  
will be poor, if propagation is even possible under this strong to severe  
proton storm.

VHF propagation via AU will not be exciting, since we don't expect a  
strong geomagnetic storm at this time.

73 de Tomas, NW7US (AAR0JA/AAA0WA)

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