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.

News from Commercial Space Watch