MIDDLE LATITUDE AURORA WATCH

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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
Sun-Earth Alert

Solar Terrestrial Dispatch
http://www.spacew.com

11 July 2003

MIDDLE LATITUDE AURORA WATCH

The "northern lights" may become sporadically visible over middle
latitude regions of North America and Europe tonight. Effects of a well
placed solar coronal hole have resulted in increasing solar wind velocities
in space that are supporting the development of occasional auroral substorms.

A middle latitude aurora watch has been issued and is valid through
tonight and tommorrow. Details follow below.

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MIDDLE LATITUDE AURORAL ACTIVITY WATCH

WATCH ISSUED: 06:05 UTC, 11 JULY 2003

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VALID BEGINNING AT: EFFECTIVE IMMEDIATELY
VALID UNTIL: 23:00 UTC (7 pm EDT) ON 12 JULY

HIGH RISK PERIOD: 11 - 12 JULY (UTC DAYS)
MODERATE RISK PERIOD: 11 JULY - 12 JULY

PREDICTED ACTIVITY INDICES: 25, 25, 20, 15 (11 JULY - 14 JULY)

POTENTIAL MAGNITUDE OF MIDDLE LATITUDE AURORAL ACTIVITY: MODERATE

POTENTIAL DURATION OF THIS ACTIVITY: MAIN BELT = VARIABLE
MINOR BELT = 24 TO 48 HOURS

ESTIMATED OPTIMUM OBSERVING CONDITIONS: NEAR LOCAL MIDNIGHT

EXPECTED LUNAR INTERFERENCE: MODERATE TO HIGH

OVERALL OPPORTUNITY FOR OBSERVATIONS FROM MIDDLE LATITUDES: FAIR TO POOR

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

NORTHERN WASHINGTON STATE TO SOUTHERN MONTANA TO SOUTH DAKOTA TO CENTRAL
MINNESOTA TO NORTHERN WISCONSIN TO CENTRAL MICHIGAN TO NORTHERN NEW YORK
STATE TO MAINE.


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

NORTHERN UNITED KINGDOM TO NORTHERN DENMARK AND POSSIBLY EXTREME NORTHERN
GERMANY TO SOUTHERN SWEDEN TO SOUTHERN FINLAND AND POSSIBLY LATVIA AND
ESTONIA TO NORTH-CENTRAL RUSSIA.

NEW ZEALAND AND SOUTH EASTERN REGIONS OF AUSTRALIA MAY ALSO OBSERVE
PERIODS OF ACTIVITY.

SYNOPSIS...

A strong and sustained southward turning over the IMF has been observed
over the last 10 hours that has resulted in periods of destabilized higher
latitude auroral activity. Low solar wind velocities are minimizing the
impact of these favorable solar magnetic fields. However, a higher velocity
solar wind stream is expected to begin influencing the Earth over the next 24
hours. If the fields remain southward, the strengthening solar wind velocity
could promote the production of periods of moderately strong auroral
substorming over the next 12 to 24 hours. As a result, a middle latitude
auroral activity watch has been issued.

UPDATE: The high velocity solar wind stream from the anticipated coronal hole
disturbance are being observed now. Auroral activity has become sporadically
strengthened. Some equatorward migration of the auroral oval has also been
observed that may help promote middle latitude sightings.

This watch will remain valid through 23:00 UTC (7 pm EDT) on
12 July. 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 Watch **