[NevadaARES] NOAA -- G3 Geomagnetic storm to hit Earth on Friday Oct 24

[Paul Cavnar]

Oct. 22, 2003 � 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.

     G 3
     Strong
     Power systems: voltage corrections may be required, false alarms
triggered on some protection devices.

      Spacecraft operations: surface charging may occur on satellite
components, drag may increase on low-Earth-orbit satellites, and corrections
may be needed for orientation problems.

      Other systems: intermittent satellite navigation and low-frequency
radio navigation problems may occur, HF radio may be intermittent, and
aurora has been seen as low as Illinois and Oregon (typically 50�
geomagnetic lat.)**.
     Kp = 7
     200 per cycle
     (130 days per cycle)