Sunspot Activity & Radio Blackouts

Wed Jul 24 05:11:13 UTC 2002

For anyone that operates a wireless network or a
copper based network:

Official Space Weather Advisory issued by NOAA Space
Environment Center
Boulder, Colorado, USA

SPACE WEATHER ADVISORY BULLETIN #02- 2
2002 July 23 at 12:00 p.m. MDT (2002 July 23 1800 UTC)

**** ( CORRECTED ) MAJOR SUNSPOT ACTITVITY ****

A major sunspot region has rotated onto the visible
face of the sun. 
This region, designated as Region 39 by NOAA Space
Environment Center
forecasters, is believed to have been the source of
three large coronal
mass ejections on the far side of the sun beginning on
July 16.  This
region will rotate across the visible side of the sun
over the next two
weeks and is expected to produce more solar activity.

Since appearing on the visible side yesterday (July
22) this region has
already produced a major flare at 6:35 pm Mountain
Daylight Time (MDT)
on July 22 (0035, July 23 UTC).  Radio blackouts
reached category R3
(Strong) on the NOAA space weather scales.  In
response to the major
flare, a geomagnetic storm is possible and is expected
to begin between
8:00 pm MDT on July 23 and 8 am MDT on July 24 (0200 -
1400, July 24
UTC). The geomagnetic storm may reach category G2
(moderate) levels on
the NOAA space weather scales.

Category R3 radio blackouts result in widespread HF
radio communication
outages on the dayside of the Earth and can also
degrade low frequency
navigation signals.  Category G2 geomagnetic storms
can lead to minor
problems with electrical power systems, spacecraft
operations,
communications systems, and some navigational systems.
  Aurora
Borealis / Australis (northern / southern lights) may
be seen down into
the mid latitudes (New York, Madison, Boise,
Vladivostok,  Rome,
Tasmania, Wellington - NZ, Puerto Montt - Chile)

Data used to provide space weather services are
contributed by NOAA, 
USAF, NASA, NSF, USGS, the International Space
Environment Services 
and other observatories, universities, and
institutions. For more 
information, including email services, see SEC's Space
Weather 
Advisories Web site http://sec.noaa.gov/advisories or
(303) 497-5127.
The NOAA Public Affairs contact is Barbara McGehan at 
Barbara.McGehan at noaa.gov or (303) 497-6288.