Official Space Weather Advisory issued by NOAA Space Environment Center
Boulder, Colorado, USA

2005 September 09 at 7:32 a.m. MDT (2005 September 09 1332 UTC)


NOAA sunspot Region 808, which yielded a powerful X17 flare (R4 radio
blackout) on 07 Sep, continues to produce significant activity. Over
the past 24 hours, this region produced several more major flares to
include three X-class flares, which resulted in R3 radio blackouts, and
several M-class flares producing R1 and R2 radio blackouts. An S2
radiation storm began soon after the X17 flare on 07 Sep and remains in

Active Region 808 is currently located near the southeast limb of the
visible solar surface. This region is a large and very complex sunspot
cluster, which is still rotating into view. Early indications are that
it is almost nine times the size of Earth. Over the next several days
this region will rotate towards center disk where solar activity is
much more likely to impact Earth. A powerful and very fast coronal mass
ejection (CME) accompanied the X17 flare on 07 Sep. The magnetic cloud
associated with this CME will not directly impact Earth; however, a
lesser impact is expected today which will likely result in G1 through
G3 geomagnetic storm conditions.

Expect continued significant solar flares from this region as it makes
its passage across the visible disk over the next 11 days. Radiation
storms in the S3 or even S4 levels are possible. Significant
geomagnetic storms are likely, beginning early next week as this region
moves towards the center of the visible side of the Sun.

Communications groups are already experiencing problems due to this
activity. Other agencies impacted by space weather are at increasing
risk for disruption. These include spacecraft operations and other
space activities, electric power systems, HF communications, and
navigation systems such GPS.

Data used to provide space weather services are contributed by NOAA,
USAF, NASA, NSF, USGS, the International Space Environment Services
and other observatories, universities, and institutions. More
information is available at SEC's Web site