MIDDLE LATITUDE AURORAL ACTIVITY WARNING

[Thomas Sävert]

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This Is SKY & TELESCOPE's AstroAlert for Sun-Earth Interactions
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A s t r o A l e r t

11 September 2005

Solar Terrestrial Dispatch
www.spacew.com


MIDDLE LATITUDE AURORAL ACTIVITY WARNING - 11-14 SEPTEMBER

A middle latitude auroral activity warning has been issued for the next
several days. Intense solar flare activity continues. The associated high
velocity coronal mass ejections are beginning to become more heavily directed
toward the Earth. Several smaller impacts were observed over the last 24 to
48 hours from solar activity that occurred when sunspot complex 10808 was on
the eastern limb of the Sun. But now, the region has rotated sufficiently far
to produce stronger Earthward-directed impacts.

The latest impact was observed near 01:19 UTC on 11 September (9:19 pm
EDT on 10 September). This disturbance has the potential to produce periods
of minor to major auroral storm conditions during the next 12 to 24 hours.
Combining this disturbance with several others that are anticipated during
the next 48 hours may result in a more volatile mixture of space weather
conditions, perhaps capable of producing significant auroral storm activity
during the next week. Observers across the United States and Europe (even
toward the lower latitudes of the central/southern states) may spot periods
of activity during the next week.

Active sunspot Region 10808 remains exceptionally complex and volatile.
It has produced two X-class flares within the last 12 hours (the largest
being a class X2.1 event at 22:11 UTC (6:11 pm EDT) on 10 September.
Additional strong X-class flares are expected in the coming days. With each
passing day, the trajectory of the ejected mass from these events will impact
the Earth more directly, resulting in greater opportunities for observers to
spot auroral activity.

The official auroral activity warning statement is appended below. Note
the statement indicating there is a good chance the warning may be extended
beyond the 14 September deadline.


MIDDLE LATITUDE AURORAL ACTIVITY WARNING
Issued: 01:45 UTC on 11 September 2005
Solar Terrestrial Dispatch
www.spacew.com


VALID BEGINNING AT: EFFECTIVE IMMEDIATELY
VALID UNTIL: 23:00 UTC (6 pm EST) ON 14 SEPTEMBER

HIGH RISK PERIOD: 11-13 SEPTEMBER (UTC DAYS)
MODERATE RISK PERIOD: 11-14 SEPTEMBER

PREDICTED ACTIVITY INDICES: 50, 40, 40, 20 (11 - 14 SEPTEMBER)

POTENTIAL MAGNITUDE OF MIDDLE LATITUDE AURORAL ACTIVITY: MODERATE TO HIGH

POTENTIAL DURATION OF THIS ACTIVITY: MAIN BELT = 24-72 HOURS
MINOR BELT = 72-96 HOURS

ESTIMATED OPTIMUM OBSERVING CONDITIONS: NEAR OR AFTER LOCAL MIDNIGHT

EXPECTED LUNAR INTERFERENCE: LOW TO MODERATE

OVERALL OPPORTUNITY FOR OBSERVATIONS FROM MIDDLE LATITUDES: FAIR TO GOOD

AURORAL ACTIVITY *MAY* BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...
(THIS LINE IS VALID *ONLY* IF FAVORABLE STORM CONDITIONS OCCUR)

OREGON TO SOUTHERN IDAHO AND NORTHERN UTAH TO WYOMING TO NEBRASKA TO
NORTHERN MISSOURI TO SOUTHERN ILLINOIS TO KENTUCKY TO VIRGINIA.

ACTIVITY *MAY* ALSO BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...
(THIS LINE IS VALID *ONLY* IF FAVORABLE STORM CONDITIONS OCCUR)

CENTRAL FRANCE TO NORTHERN SWITZERLAND TO SOUTHERN GERMANY TO THE CZECH
REPUBLIC TO POLAND TO CENTRAL RUSSIA.

NEW ZELAND AND SOUTHEASTERN AUSTRALIA SHOULD ALSO BE ABLE TO SPOT PERIODS
OF ACTIVITY.

SYNOPSIS...

A series of coronal mass ejections have been directed partially
Earthward over the last few days. The Earth is beginning to observe impacts
from some of the stronger events. Periods of intensifying auroral activity
will be observed during the next several days. The first of the larger
impacts occurred near 01:19 UTC on 11 September and is expected to produce
periods of minor to major auroral storm conditions, sporadically during the
next 12 to 18 hours. Additional strong impacts are expected over the next
several days. Some of these disturbances are cannibalizing other CME's, and
as a result, the potential geoeffectiveness will likely be complex and
difficult to accurately predict. Nevertheless, the potential exists for
periods of strong auroral storm conditions developing during the next several
days (at least). Near-continuous storm-level activity is possible during the
next week, if sunspot complex 10808 continues to impress with energetic flare
activity.

This warning will remain valid through 24:00 UTC (6 pm EDT) on
14 September, with a good chance that it will be extended beyond the 14th.
It will be updated or allowed to expire at that time. For updated
information, visit: http://www.spacew.com/aurora/forum.html. For real-time
plots of current activity, visit: http://www.spacew.com/plots.html

PLEASE REPORT VALID OBSERVATIONS OF AURORAL ACTIVITY TO:
http://www.spacew.com/submitsighting.html


** End of AstroAlert **

[Dennis A.]

wäre nett wenn ihr bei solchen sachen die auf englisch sind vieleicht ne kleine deutsche zusammenfassung geben könntet...ich kann zwar daraus entziffern das ne warnung für PL vom 11-14september ist aber mehr auch nicht

[Thomas Sävert]

Hi Dennis, sorry, bin wegen der Unwetter im Stress, da hab ich leider keine Zeit, das noch zu übersetzen. Wichtig für uns ist auch immer der Abschnitt:

"CENTRAL FRANCE TO NORTHERN SWITZERLAND TO SOUTHERN GERMANY TO THE CZECH REPUBLIC TO POLAND TO CENTRAL RUSSIA."

Das bedarf wohl kiner Übersetzung, dass nördlich dieser Linie Polarlichter möglich sind

Gruß, Thomas Sävert