AstroAlert: Mid-Latitude Aurora Watch - 24-25 Octo

[Joachim Uhlig]

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This Is SKY & TELESCOPE's AstroAlert for Sun-Earth Interactions =================================================================

A s t r o A l e r t

Sun-Earth Alert

Solar Terrestrial Dispatch

http://www.spacew.com

22 October 2003

MIDDLE LATITUDE AURORAL WATCH - 24-25 OCTOBER

A middle latitude auroral activity Watch has been issued for the 24 and 25 October period. A coronal mass ejection observed on 22 October has been determined to be partially Earthward directed. The disturbance has the potential to produce periods of moderately strong auroral activity over many dark-sky middle latitude locations. The moon's near-new phase will also enhance the ability to detect faint auroral emissions.

If the disturbance arrives as predicted, near the mid-UTC hours of 24 October, the best locations to observe activity will probably be extreme southern Australia, New Zealand and Europe. Timing may be poor for North America, unless the disturbance arrives later than predicted. For North Americans, the best opportunity will probably occur during the evening hours of 25 October. But a quick peek at the skies during the early morning hours of 24 October wouldn't hurt either.

Please report sightings of activity to the Global Auroral Activity Observation Network at: www.spacew.com/submitsighting.html

Additional significant coronal mass ejections are possible over the next 2 weeks, particularly if the two major sunspot regions continue to produce energetic activity. Whether they are able to keep up the pace remains an open question.

The mid-latitude watch statement follows below:

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MIDDLE LATITUDE AURORAL ACTIVITY WATCH

WATCH ISSUED: 04:30 UTC, 23 OCTOBER 2003

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VALID BEGINNING AT: 00:00 UTC 24 OCTOBER
VALID UNTIL: 23:00 UTC (7 pm EDT) ON 25 OCTOBER

HIGH RISK PERIOD: 24 OCTOBER (UTC DAYS)
MODERATE RISK PERIOD: 24 - 25 OCTOBER

PREDICTED ACTIVITY INDICES: 15, 40, 20, 15 (23 OCTOBER - 26 OCTOBER)

POTENTIAL MAGNITUDE OF MIDDLE LATITUDE AURORAL ACTIVITY: MODERATE

POTENTIAL DURATION OF THIS ACTIVITY: MAIN BELT = 12 TO 18 HOURS

MINOR BELT = 18 TO 24 HOURS

ESTIMATED OPTIMUM OBSERVING CONDITIONS: NEAR LOCAL MIDNIGHT

EXPECTED LUNAR INTERFERENCE: NONE

OVERALL OPPORTUNITY FOR OBSERVATIONS FROM MIDDLE LATITUDES: FAIR TO GOOD

AURORAL ACTIVITY *MAY* BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...

OREGON TO SOUTHERN IDAHO TO WYOMING TO NORTHERN NEBRASKA TO IOWA TO

NORTHERN ILLINOIS TO NORTHERN INDIANA TO OHIO TO PENNSYLVANIA TO NEW

JERSEY.

ACTIVITY *MAY* ALSO BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...

EXTREME NORTHERN FRANCE TO BELGIUM TO CENTRAL GERMANY TO NORTHERN POLAND

TO LITHUANIA TO LATVIA TO NORTH-CENTRAL RUSSIA.

NEW ZEALAND AND EXTREME SOUTHERN (PARTICULARLY SOUTHEASTERN) REGIONS OF

AUSTRALIA MAY ALSO OBSERVE PERIODS OF ACTIVITY.

SYNOPSIS...

A moderately strong coronal mass ejection associated with multiple eruptive solar centers was observed early in the UTC day of 22 October and is expected to impact the Earth during the mid-UTC day of 24 October. The arrival of this disturbance could result in periods of major auroral storming. If the timing of the arrival of this disturbance is accurate, the best locations to observe activity could be New Zealand and Australia and northern Russia. There is also fairly good chance regions of Europe may also be well placed for observing activity, particularly if the disturbance arrives later than predicted.

This watch will remain valid through 23:00 UTC (7 pm EDT) on 25 October. It will then be updated or allowed to expire. 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 OBSERVATIONS OF AURORAL ACTIVITY TO:

http://www.spacew.com/submitsighting.html

** End of the AstroAlert Bulletin **