Space Weather Message Code: WARK07
Serial Number: 27
Issue Time: 2005 Aug 24 0948 UTC

WARNING: Geomagnetic K-index of 7 or greater expected Valid From: 2005 Aug 24 0948 UTC Valid To: 2005 Aug 24 1500 UTC Warning Condition: Onset NOAA Scale: G3 or greater - Strong to Extreme



NOAA Space Weather Scale descriptions can be found at www.sec.noaa.gov/NOAAscales

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

SPACE WEATHER ADVISORY BULLETIN #05- 6
2005 August 24 at 10:52 a.m. MDT (2005 August 24 1652 UTC)

**** EXTREME GEOMAGNETIC STORM ****

Forecasters at the NOAA's Space Environment Center (SEC) in Boulder, Colo., observed an extreme (G5) geomagnetic storm, beginning on August 24 at 2:12 a.m. EDT. Solar flares on August 22 produced minor to moderate radio blackouts (R1 and R2) and a moderated radiation storm (S2). Also, two large Earth-directed coronal mass ejections occurred on August 22, which resulted in today's extreme geomagnetic storming.
The most intense period of geomagnetic storming occurred between 4:00 a.m. and 7:00 a.m. EDT today. The storm is currently subsiding; however, further, less intense geomagnetic storming is expected through tomorrow.

This solar activity originated from a complex sunspot cluster known as NOAA Region 798. Minor to moderated radio blackouts are still possible today. The radiation storm currently in progress is expected to subside by August 25. This active region is currently rotating around the west limb of the Sun and will no longer be visible from Earth after today.

Agencies impacted by space weather storms may experience disruptions through August 25. These include spacecraft operations, electric power systems, HF communications, and navigations systems.

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