The solar regions that produced dramatic space weather activity in late October and early November returned to the visible side of the sun, according to the NOAA Space Environment Center in Boulder, Colo. The area known as NOAA Region 501 already produced a moderate radio blackout, R2 on the NOAA space weather scales, and spawned a severe, or G4, geomagnetic storm, which began Thursday, Nov. 20 at 2:04 a.m. EST, and is strengthening.

The last flurry of activity associated with these regions produced perhaps the largest radio blackout (R5) measured by the NOAA GOES satellite in almost thirty years. Moderate to strong activity is possible for the next two weeks as the sun spot regions make their transit across the sun.

It is unusual for regions to return a second time with the intensity they produced the first time around. NOAA space weather forecaster Larry Combs said, "The uniqueness of this activity continues to be of interest. We're still keeping a close watch on these regions to see if they produce additional fireworks."

Aurora Borealis or northern lights may be possible Thursday night in northern latitudes.

These large sunspot groups have been re-numbered as NOAA Region 501 (previously region 484), 507 (previously Region 488), and 508 (previously Region 486). All three regions have decreased in size since the last rotation, however, they are bright and show considerable magnetic complexity.

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