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

SPACE WEATHER ADVISORY BULLETIN #05- 9
2005 September 09 at 7:32 a.m. MDT (2005 September 09 1332 UTC)

**** ACTIVE SUNSPOT GROUP CONTINUES TO PRODUCE SIGNIFICANT FLARES ****

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
progress.

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 http://sec.noaa.gov