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

SPACE WEATHER ADVISORY BULLETIN #05- 5
2005 July 30 at 12:05 p.m. MDT (2005 July 30 1805 UTC)

**** STRONG MAJOR FLARE OCCURS ON SUN ****

A strong radio blackout (R3) occurred today at 30/0635 UTC (12:35 am
MDT) due to a major flare on the Sun. The source of the flare was NOAA active sunspot Region 792, which is the return of old NOAA Region 786, as mentioned in the previous advisory bulletin #05-4. Due to the location of Region 792 on the Sun, the resulting radiation storm level is most likely to be minor (S1), although there is a slight possibility for moderate levels (S2). In addition there is only a slight chance for a minor geomagnetic storm (G1). However, additional activity is likely from Region 792 as it rotates across the Sun and additional major events could lead to higher levels of radiation storms and geomagnetic storms. Agencies impacted by solar flare radio blackouts, geomagnetic storms, and solar radiation storms should continue to closely monitor the space environment during the rotation of Region 792 across the Sun between now and its anticipated departure on 12 August.

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