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September 25, 2001 — A fast moving solar storm is approaching Earth, according to forecasters at NOAA's Space Environment Center in Boulder, Colo. The expected geomagnetic storm is rated strong or a G-3 on the NOAA Space Weather Scales. Forecasters are predicting the storm will impact the Earth's magnetic field sometime after 8:00 p.m. EDT Tuesday and continue for 24 to 36 hours. Aurora Borealis, or northern lights, may be visible Tuesday evening in the northern latitudes and possibly over a significant portion of the continental U. S. (Click NASA/European Space Agency SOHO satellite image for larger view of solar activity taken Sept. 25, 2001. Click here for animation. This is a large file.)

The flare, rated as an X2.6, erupted on September 24 at 6:30 a.m. EDT from an active region on the sun that forecasters will continue to watch. "Region 9632 is located almost at the center of the sun now and will be visible for another seven days," said Joe Kunches, acting chief of space weather operations. "We could easily get another storm spawned from that region."

Forecasters say that a solar radiation storm is also currently in progress and is at a strong level, an S-3 on the NOAA Space Weather Scales, which run 1-5. That could increase to a severe level (S-4) when the geomagnetic storm hits later Tuesday evening. Airlines sometimes re-route their flights over the poles when solar radiation storms reach this level.
Strong geomagnetic storms and solar radiation storms can cause satellites to experience surface charging and orientation problems, and power systems can also be affected. Such storms can also interfere with high frequency radio communications. A full halo coronal mass ejection, or CME, was associated with the event, which was observed by the Solar and Heliospheric Observatory (SOHO) mission operations center, which is run by NASA and the European Space Agency.

Kunches says that the magnetic storm data over the last 70 years shows that magnetic storms have a tendency to occur more often around the vernal and autumnal equinox months. "Scientists debate about the cause of this clustering. It is possibly the tilt of the Earth's dipole axis in relation to the incoming solar wind that enhances the geomagnetic storms," says Kunches.

NOAA's Space Environment Center is the nation's official source of space weather alerts and warnings and continually monitors and forecasts Earth's space environment.

Relevant Web Sites
NOAA's Space Environment Center — Click "Space Weather Now" for the latest information on solar activity.

NOAA's Space Weather Scales

NOAA Space Weather Advisories

Today's Space Weather Forecast — Includes the latest image of the sun from Earth-based telescopes positioned around the world.

Real-time images of the Sun from NASA's SOHO Satellite

SPACE WEATHER - WHAT IS IT AND WHY DO WE WANT TO KNOW ABOUT IT?

NEW NOAA SPACE WEATHER SCALES MAKE SOLAR MAX EFFECTS MORE PREDICTABLE

Media Contact:
Barbara McGehan, NOAA Space Environment Center, Boulder, Colo., at (303) 497-6288