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
unreliable.
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)
: Propagation Editor for CQ, CQ VHF, Popular Communications :
: Creator; live propagation center http://prop.hfradio.org/ :
: Associate Member of Propagation Studies Committee of RSGB :
: US Army Miltary Affiliate Radio Service (MARS) SMD AAA0WA :
: 122.93W 47.67N / Brinnon, Washington USA CN87 CW/SSB/DIGI :
: Website/software/database design http://newwebmakers.com/ :
: 10x56526, FISTS 7055, FISTS NW 57, Lighthouse Society 144 :
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