[GeoStL] NGR: AURORA WARNING
- From: "M. Bollinger" <lazylightning3@xxxxxxxxx>
- To: SLAGA <geocaching@xxxxxxxxxxxxx>
- Date: Wed, 14 Sep 2005 11:35:48 -0700 (PDT)
-
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A s t r o A l e r t
14 September 2005
Solar Terrestrial Dispatch
www.spacew.com
NEW X-CLASS SOLAR FLARES EXTEND AURORA WARNING
Active sunspot region 10808 produced two new
X-class solar x-ray flares
during the last 24 hours. The most energetic of these
produced an
Earthward-directed coronal mass ejection that is
expected to impact the Earth
late this afternoon or evening. The impact is expected
to reignite auroral
storm conditions. If it arrives as-expected, the
resulting intensification of
auroral activity may place North America in a good
position for observing the
activity TONIGHT. The mid-latitude auroral activity
warning has been extended
through to 16 September. The next 3 to 4 days will be
critical, as this is
the time that Region 808 is "pointed" most directly
toward the Earth. Coronal
mass ejections follow essentially straight
trajectories to the Earth, unlike
the energetic protons that stream from strong solar
events.
For spacecraft and their sensitivity to energetic
protons (the radiation
environment), the most vulnerable period will be later
this week when Region
808 begins to approach the western solar limb. At that
time, the Earth should
be best "connected" to the magnetic field lines that
emanate from Region 808
and gradually spiral outward toward the Earth in an
archimedes-type spiral
pattern. Energetic protons from major solar flares
often reach the Earth
fastest (and are associated with the highest energies
and densities) when the
Earth is magnetically connected to the flaring region.
This is because
enegetic protons are charged particles, and as such
they prefer to follow the
magnetic lines of force outward from the Sun.
The updated warning statement is appended below.
MIDDLE LATITUDE AURORAL ACTIVITY WARNING
Updated: 11:45 UTC on 14 September 2005
Solar Terrestrial Dispatch
www.spacew.com
VALID BEGINNING AT: EFFECTIVE IMMEDIATELY
VALID UNTIL: 23:00 UTC (5 pm EDT) ON 16 SEPTEMBER
HIGH RISK PERIOD: 14-15 SEPTEMBER (UTC DAYS)
MODERATE RISK PERIOD: 14-16 SEPTEMBER
PREDICTED ACTIVITY INDICES: 30, 50, 30, 20 (14 - 17
SEPTEMBER)
POTENTIAL MAGNITUDE OF MIDDLE LATITUDE AURORAL
ACTIVITY: MODERATE TO HIGH
POTENTIAL DURATION OF THIS ACTIVITY: MAIN BELT = 24
HOURS
MINOR BELT = 24-48
HOURS
ESTIMATED OPTIMUM OBSERVING CONDITIONS: NEAR OR AFTER
LOCAL MIDNIGHT
EXPECTED LUNAR INTERFERENCE: 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...
Active region 10808 continues to produce
energetic solar flare activity.
The latest X-class flare was associated with an
Earthward-directed
(full-halo) coronal mass ejection that is expected to
arrive at the Earth
near the end of the UTC day of 14 September (for North
American observers,
this translates to the late afternoon and/or evening
hours of Wednesday, 14
September). This disturbance will have the potential
to produce periods of
moderate to strong auroral storm conditions.
Observations should
be possible over wide-spread mid-latitude locations.
We are expecting to see
the passage of a magnetic cloud with this disturbance,
which could further
enhance the potential for storm conditions (preceded
or succeded by quieter
conditions as the IMF rotates away from a favorable
orientation).
This warning will remain valid through 23:00 UTC
(5 pm EDT) on
16 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 **
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