From: LARRY KLAES (ljk4@msn.com)
Date: Mon Nov 11 2002 - 08:28:56 PST
----- Original Message -----
From: Cary Oler
Sent: Sunday, November 10, 2002 9:24 PM
To: sun-earth@SkyandTelescope.com
Subject: AstroAlert: Middle Latitude Auroral Activity Warning
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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
10 November 2002
MIDDLE LATITUDE AURORAL ACTIVITY WARNING
Two strong coronal mass ejections were observed yesterday. Each appeared
to contain mass moving earthward at relatively high velocity. The activity
began at 13:23 UTC (8:23 am EST) on 09 November following a near-major solar
proton flare from active sunspot complex 10180. This spot complex has been
developing in both size and complexity over the last week and finally managed
to produce an energetic solar flare and a full halo coronal mass ejection
(CME). The velocity of the CME was estimated near 1,800 km/sec. Most CMEs
are associated with a velocity not usually higher than 600 km/sec. A second
coronal mass ejection was observed at 03:21 UTC on 10 November (10:21 pm EST
on 09 November) that was also estimated to be travelling at a similar
velocity. It too is believed to contain an earthward-directed component.
The first of these coronal mass ejections is expected to arrive on 11
November and has the potential to produce periods of auroral storming. A
middle latitude auroral activity warning has been issued for 11 and 12
November. North American observers across the central to northern tier of the
United States should be aware of the possibility of northern lights activity
on the evenings of 10 (late evening tonight [after midnight EST] through to
sunrise) and 11 November (early evening through early morning hours).
We believe the first coronal mass ejection may impact sometime around
the hours of 05:00 UTC (midnight EST tonight), give or take several hours.
The Space Environment Center estimates impact will be somewhat later, "by the
latter half of UTC 11 November."
The middle latitude auroral activity warning statement follows below:
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
MIDDLE LATITUDE AURORAL ACTIVITY WARNING
ISSUED: 23:50 UTC, 09 NOVEMBER 2002
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
*** POTENTIAL FOR MODERATE TO HIGH ACTIVITY EXISTS ***
For North Americans, begin watching the evening of 10 November.
VALID BEGINNING AT: 21:00 UTC ON 10 NOVEMBER (4 PM EST)
VALID UNTIL: 19:00 UTC (2 PM EST) ON 12 NOVEMBER
HIGH RISK PERIOD: 07 NOVEMBER (UTC DAYS)
MODERATE RISK PERIOD: 07 - 08 NOVEMBER
PREDICTED ACTIVITY INDICES: 23, 40, 25, 12 (10 NOV - 13 NOV)
POTENTIAL MAGNITUDE OF MIDDLE LATITUDE AURORAL ACTIVITY: MODERATE TO HIGH
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: MODERATE TO HIGH
OVERALL OPPORTUNITY FOR OBSERVATIONS FROM MIDDLE LATITUDES: FAIR TO GOOD
AURORAL ACTIVITY *MAY* BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...
OREGON TO EXTREME NORTHERN UTAH TO WYOMING TO NORTHERN NEBRASKA TO IOWA TO
ILLINOIS TO INDIANA TO OHIO TO WEST VIRGINIA TO NORTHERN VIRGINIA AND
MARYLAND.
ACTIVITY *MAY* ALSO BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...
NORTHERN FRANCE TO BELGIUM TO CENTRAL GERMANY TO CENTRAL POLAND TO
NORTHERN BELARUS TO NORTH-CENTRAL RUSSIA. ACTIVITY MAY ALSO BE OBSERVED
FROM NEW ZEALAND AND SOUTHEASTERN AUSTRALIA.
SYNOPSIS...
A strong solar coronal mass ejection associated with a near-major class
M4.6/2B x-ray proton flare from sunspot complex number 180 was observed at
13:23 UTC on 09 November (8:23 am EST). This high velocity coronal mass
ejection is estimated to be travelling near 1,800 km/sec. Although a strong
component of the CME is directed away from the Earth, a moderate
Earthward-directed component also exists. This disturbance is expected to
merge with a coronal hole based solar wind disturbance and could impact the
Earth early in the UTC day of 11 November (evening hours of 10 November
[Sunday night] for North Americans).
The Space Environment Center and the USAF are expecting the disturbance
to impact late in the UTC day of 11 November and produce only a mild
enhancement of activity (if their prediction holds true, no auroral activity
would be observed over North American middle latitudes at all - and high
latitudes wouldn't expect to see anything until the evening of 11 November
[Monday night]).
We (STD) believe the disturbance will impact much earlier than the
SEC/USAF estimate. Our estimate is for impact during the early UTC day of 11
November (perhaps around 05:00 UTC [near midnight on the evening of 10
November EST], +/- several hours). We also suggest this disturbance could
produce a moderately strong impact at the Earth. We expect periods of minor
to major geomagnetic and auroral storm activity to accompany this
disturbance. There is a fair chance middle latitudes may spot periods of
moderate to strong auroral activity during the UTC days of 11 and 12 November
(North American evenings of 10 and 11 November).
This warning will remain in effect until 19:00 UTC on 12 November. It
will then be downgraded to a watch through 19:00 UTC on 13 November
afterwhich it will probably be allowed to expire. If the disturbance proves
to be less geoeffective than anticipated, it may be downgraded earlier than
this.
PLEASE REPORT OBSERVATIONS OF AURORAL ACTIVITY TO:
http://www.spacew.com/submitsighting.html
CURRENT REPORTED SIGHTINGS OF ACTIVITY MAY BE FOUND AT:
http://www.spacew.com/www/auroras.html
CURRENT GALLERY OF ASTRONOMICAL AND AURORA IMAGES:
http://www.spacew.com/gallery
DISCUSSIONS OF ACTIVITY
http://www.spacew.com/aurora/forum.html
** End of the AstroAlert Bulletin **
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