[R-390] Geomagnetic disturbances, coming up

[Goodman, Paul K2ORC]

A cut and paste from the AM Window Bulletin Board.  The
next week or so could be rather interesting.  If nothing
else, should be some spectacular aurora displays!

Paul, K2ORC
= = = = = 
Thanks to Tomas, NW7US for this info:

Minor to major storm levels of geomagnetic disturbances are
expected as early as in the late afternoon on July 24 over
North America, with increases in geomagnetic activity
starting today (July 23). The next week may see extreme
solar flare activity.

Region 10039 (Catania sunspot group #35), which produced
the X3.3 flare of July 20, struck again on July 23,
producing an X4.8 flare with the X-ray flux peaking at
0035Z. This solar flare is a proton-producing flare and the
energetic protons are expected to reach the Earth and begin
slowly enhancing the radiation in the near-Earth space
environment by the end of today (July 23).

Region 10039 has rotated fully into view at the southeast
limb. This region has the potential to produce occasional
X10+ flares. During the X4.8 flare, a large and fast full
halo Coronal Mass Ejection (CME) was observed with a
leading edge speed above 1700km/s. Although the fastest
part of the CME headed eastwards, Earth should receive an
impact on July 24, resulting in a severely disturbed
geomagnetic field for 12 to 24 hours after the impact. This
event is very similar to the eruption of July 20, probably
at the origin of the geomagnetic disturbances of yesterday
(July 22) around noon (Zulu). But this one will be stronger
and more geoeffective. Minor to major storm levels of
geomagnetic disturbances are thus expected as early as in
the afternoon of July 25 (late afternoon on July 24 over
North America).

Additional major X-class solar flares from this Region over
the next two weeks might produce very active and 
geomagnetically stormy conditions, the likes of which we
have not observed in over 10 years. If Region 10039 holds
true to its potential, the spot complex will continue to
produce very energetic solar activity about once every 2 to
3 days as it rotates across the face of the Sun. The Region
is well-placed for producing large, geoeffective impacts on
the earth, and it will remain visible for about another 12
to 13 days. The next week or two could see some
considerable
solar radiation storms, auroral storm activity, ionospheric
storming, and significant geomagnetic storming. Similar
historic periods have produced heavy Auroral events, radio
blackouts, and so on. These Auroral event have been visible
throughout the continental United States and Canada, even
into parts of Mexico. New Zealand, Australia, Southern
Africa, and South America have witnessed the "Southern
Lights" during such events. This type of Aurora might
happen as early as July 24. Storms of this magnitude
("superstorms") occur on average once every six years or
so. It has now been about 12 years since the Earth was hit
by a superstorm.

Shortwave (High Frequency) propagation will experience
fadeouts, with possible R1 to R2 radio blackouts from July
23 through July 25. Long distance medium wave (AM) band
propagation along east-west paths over high and upper
middle latitudes is poor to very poor. If we get the
Aurora, look for Auroral-mode propagation.



=====
Paul R. Goodman, K2ORC
Where AM Radio, Boat Anchors
and Vintage Broadcast Equipment
are alive and well!
AMI #1319 - AWA - ARRL

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