NEWINGTON, CT, Jan 17, 2005--This may be the week to check the sky for a
display of northern lights and to check the radio for auroral
propagation on VHF. A long-duration X-class solar flare earlier today
(UTC) from giant sunspot 720 is expected to generate a major geomagnetic
storm when it arrives January 18 or 19 (UTC). Spaceweather.com has
issued an aurora alert. X-class flares are major events that can trigger
worldwide radio blackouts and long-lasting radiation storms. A space
weather alert from the National Oceanic and Atmospheric Administration
(NOAA) Space Environment Center (SEC) warns that a geomagnetic K index
of 6 is expected through today UTC. A watch for a geomagnetic A index of
100 also remains in effect through January 17 UTC. NOAA says active
sunspot region 720 has produced several strong solar events.

"Short-wave radio communications through the sunlit hemisphere of Earth
experienced significant signal degradation during these solar flares,"
said a NOAA Space Weather Advisory issued at 1937 UTC today. "Associated
strong geomagnetic and radiation storms are under way." NOAA says five
large solar flares (CMEs) have produced moderate to strong radio
blackouts since Saturday. The largest was measured at X3.8 at 0659
today.

The Solar Terrestrial Activity Report said NASA's Advanced Composition
Explorer (ACE) observed a strong increase in proton levels. "Currently,
all solar wind measurements are invalid due to the proton storm," the
report continued. "Severe geomagnetic storming has been observed since
just before noon." NASA says solar wind speeds resulting from the huge
coronal mass ejection (CME) or ejections earlier today have compromised
the ability of the ACE Solar Wind Electron, Proton, and Alpha Monitor
(SWEPAM) to measure them.

The geomagnetic field is expected to generate active to severe storm
conditions for the remainder of January 17 with unsettled to major storm
conditions on January 18, due to the CME's effects.

Calling active region 720 "a large and complex sunspot cluster," NOAA
predicted further major eruptions are possible from this region before
it rotates out of view on January 22.

"Agencies impacted by solar flare radio blackouts, geomagnetic storms
and solar radiation storms should continue to closely monitor the space
environment through the remainder of this week," the NOAA's bulletin
advised.