Intense Active Regions Emerge on the Sun

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

SPACE WEATHER ADVISORY BULLETIN #03- 2

2003 October 21 at 06:11 p.m. MDT (2003 October 22 0011 UTC)

**** INTENSE ACTIVE REGIONS EMERGE ON SUN ****

Two very dynamic centers of activity have emerged on the sun. NOAA
Region 484 developed rapidly over the past three days and is now one of
the largest sunspot clusters to emerge during Solar Cycle 23,
approximately 10 times larger than Earth. This region, which is nearing
the center of the solar disk, already produced a major flare (category
R3 Radio Blackout on the NOAA Space Weather Scales) on 19 October at
1650 UTC. The region continues to grow, and additional substantial
flare activity is likely.

A second intense active region is rotating around the southeast limb of
the sun. Though the sunspot group is not yet visible, two powerful
eruptions occurred on 21 October as seen from the LASCO instrument on
the SOHO spacecraft. These eruptions may herald the arrival of a
volatile active center with the potential to impact various Earth
systems.

Further major eruptions are possible from these active regions as they
rotate across the face of the sun over the next two weeks. Agencies
impacted by solar flare radio blackouts, geomagnetic storms, and solar
radiation storms may experience disruptions over this two-week period.
These include satellite and other spacecraft operations, power systems,
HF communications, and navigation systems.

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@noaa.gov or (303) 497-6288.