Forecasters at the NOAA Space Environment Center in Boulder, Colo., observed two dynamic areas of the sun, one of which has produced a coronal mass ejection, or
CME, Wednesday morning at 3 a.m. EDT that appears to be Earth-directed. The
forecasters are predicting a strong geomagnetic storm, G-3 on the NOAA Space
Weather Scales, that should reach Earth on Friday, October 24.

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. It is about 10 times
larger than the Earth. This region, which is nearing the center of the sun,
already produced a major flare, R-3 on the NOAA Space Weather Scales, producing
a radio blackout on October 19 at 12:50 p.m EDT. The region continues to grow,
and additional substantial flare activity is likely.

Larry Combs, a forecaster with the NOAA Space Environment Center’s Space Weather

Operations, said that this region has developed rapidly over the last three to
four days. "It’s somewhat unusual to have this much activity when we’re
approximately three-and-a-half years past solar maximum," he said. "In fact,
just last week, solar activity was very low with an almost spotless sun." Solar
cycles of high and low activity repeat about every eleven years, and the sun has

been moving towards solar minimum for the past three years.

A second intense active region is rotating on the southeast quadrant of the sun.

Although the sunspot group is not yet visible, two powerful eruptions occurred
on October 21 as seen from the LASCO instrument on the SOHO spacecraft. These
eruptions may herald the arrival of another 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. Satellite and other
spacecraft operations, power systems, high frequency communications, and
navigation systems may experience disruptions over this two-week period.

NOAA is dedicated to enhancing economic security and national safety through the

prediction and research of weather and climate-related events and providing
environmental stewardship of the nation’s coastal and marine resources. NOAA is
part of the U.S. Department of Commerce.

Relevant Web Sites

* NOAA Space Environment Center

* NOAA Space Weather Scales

* Latest SOHO images

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Image from the SOHO spacecraft of the intense solar activity on the sun taken
Oct. 21, 2003. Credit: SOHO