NOAA / Space Weather Prediction Center

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Space Weather Advisories

Advisory Bulletins

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

Space Weather Advisory Bulletins are issued when conditions occur that are thought to be of interest to the public.


SPACE WEATHER ADVISORY BULLETIN #11- 4
2011 September 26 at 03:00 p.m. MDT (2011 September 26 2100 UTC)

**** EARLY AUTUMN GEOMAGNETIC STORM ****

A Coronal Mass Ejection (CME) that erupted from NOAA Active Region 1302 on Saturday September 24 in conjunction with an M7 strength solar flare, arrived this morning at 1237 UT (8:37am Eastern Time). It has kicked off moderate (G2) geomagnetic storms for low latitudes, but high latitudes are seeing severe (G4) levels of activity. Aurora watchers in Asia and Europe are most favorably positioned for this event, though it may persist long enough for viewers in North America. The bulk of the CME missed the Earth, meaning the storm intensity and duration are less than what they would have been in the case of a direct hit. Region 1302 remains capable of producing more activity and will be in a favorable position for that activity to have impacts on Earth for the next 3-5 days.

For current space weather conditions see: Space Weather Now, Today's Space Weather and Space Weather Alerts


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The Space Weather categories used in the Advisory products are explained at NOAA space weather scales.

Space Weather Advisories are available here as soon as they are issued. Advisories are also distributed via email through the SWPC Product Subscription Service.

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.

Each type of advisory message has its own reference number; the last two digits of the current year and a sequential message number.

Dates and times are Mountain Daylight Time (MDT) or Mountain Standard Time (MST) followed by Coordinated Universal Time (UTC). The difference between Mountain and Universal times are MDT + 6 hours = UTC or MST + 7 hours = UTC.

More information is available at SWPC's Web site or (303) 497-5127.

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