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[RTTY] Chance of Geomagnetic Storm

To: SWL <swl@mailman.qth.net>,"SW - TheBasicsOfShortwave" <thebasicsofshortwave@yahoogroups.com>,SWARL <SWARL@yahoogroups.com>, SWBC <swbc@topica.com>,"SWL and Ham DX Club" <hamradioandshortwavedxclub@yahoogroups.com>
Subject: [RTTY] Chance of Geomagnetic Storm
From: "NW7US, Tomas" <nw7us@hfradio.org>
Date: Thu, 22 Jul 2004 13:59:54 -0700
List-post: <mailto:rtty@contesting.com>

Over the last week or so, we've been seeing very nice solar activity. Solar activity has been strong, with the 10.7-cm Flux reading a high of 175. Last night between 6 PM and midnight, from my location, I heard many 20 meter QSO's between the West Coast and Europe and other areas of the world. On Shortwave, I heard strong DX openings on higher frequencies, longer into the night.

Quite a number of flares, including a series of X-class as well as M-class flares have occurred over the last week or so. Most of them did not have any significant, associated coronal mass ejections. However, the few that occurred have caused us solar weather watchers to be on alert. So far, the elevated solar wind speed and pressure have not had too great of an affect on the Earth's geomagnetic field activity, since the Interplanetary Magnetic Field (IMF) orientation (Bz) was oriented in such a way as to not cause disturbance.

However, as of the time of writing this NW7US Propagation Bulletin, at 2030Z, 22 July 2004, the IMF is moderately oriented southward, and has been now for a long period of time (since approx. 1330Z), and has steadily increased in its southward orientation (the Bz component has steadily become more negative). This will cause the geomagnetic field to become highly active, possibly even stormy.

I am now predicting that we will see K index reading of at least 5, possibly 6, through this evening. This will degrade HF communications. The cause is the high-speed solar wind (currently near 700 km/s), and the long-duration southward orientation of the IMF, from a passing CME.

In addition, I detect possibly two coronal holes rotating into the center of the Sun. They are each located off of the Sun's equator, but due to their proximity and apparent size, they could cause long-duration enhancement of the solar wind, causing a lengthy period of continued geomagnetic activity from active to stormy levels, over the course of next week.

I will update you as conditions warrant.

73 de Tomas, NW7US (AARØJA/AAAØWA)

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