[GeoStL] NGR: MAJOR SOLAR FLARE PROMPTS AN AURORA WARNING
- From: "M. Bollinger" <lazylightning3@xxxxxxxxx>
- To: SLAGA <geocaching@xxxxxxxxxxxxx>
- Date: Sat, 14 May 2005 05:33:26 -0700 (PDT)
A s t r o A l e r t
14 May 2005
Solar Terrestrial Dispatch
www.spacew.com
MAJOR SOLAR FLARE PROMPTS AN AURORA WARNING
The Sun is known for producing energetic spurts of activity, even during
the less active periods around the solar sunspot minimum years. We are now a
little more than one year from reaching the solar minimum. The frequency of
energetic solar events has diminished over the last year, as has the number
of sunspots that pepper the face of the Sun. But as has been the case with
most solar cycles in recorded history, the Sun is not always quiet. It
occasionally hiccups and produces large and complex sunspots capable of
influencing space weather at the Earth.
We are currently experiencing one of those 'hiccups.' Several large
sunspots have appeared recently that have had the potential to produce
energetic solar flare activity. Region 10759, now nearing the central solar
meridian, spawned a major class M8.0 solar x-ray flare at 16:57 UTC on 13
May. The event was associated with strong radio bursts across the spectrum.
Such bursts have the potential to disrupt cellular phone services when the
Sun is aligned with the direction of cellular signal propagation (most
dominantly near sunrise and sunset when solar elevation angles are more
in-line with cellular signal trajectories). This event has also been blamed
for producing a weak space radiation storm, where energetic particles
(protons) arrive from the Sun travelling at near relativistic velocities.
Such storms have the potential to affect the health and stability of
satellites orbiting the Earth.
Perhaps most significantly, this solar flare was associated with a
coronal mass ejection that appears to be directed squarely at the Earth.
Sometime on 15 May (perhaps during the early to mid UTC hours of 15 May,
corresponding to the late evening to early morning hours of 14/15 May for
North Americans), this cloud of solar plasma will impact the Earth's
magnetosphere and energize it. What follows will depend upon the energy of
the impact and the orientation of the imbedded solar magnetic fields that
interact with the Earth's magnetic field. If the imbedded magnetic fields are
oriented appropriately, they will generate a potentially strong geomagnetic
storm and produce auroral activity ("northern lights") that may become
visible across extensive middle latitude regions (central United States
through perhaps central Europe, New Zealand and southern Australia).
Given our proximity to the solar minimum and the decreasing frequency of
auroral storm events, it may be prudent to watch the skies carefully for
activity this weekend (particularly on Saturday and Sunday nights). Current
information can be found at www.spacew.com or www.sec.noaa.gov. Those who
succeed in observing activity are encouraged to report their observations to
the Global Auroral Activity Observation Network at:
www.spacew.com/submitsighting.html. A near-realtime accounting of reported
sightings can be found at: www.spacew.com/www/auroras.html.
This disturbance is expected to last roughly 18 to 24 hours and may only
provide an opportunity to observe auroral activity for one evening. There may
be additional opportunities to observe activity over the coming week, as the
active sunspot complex responsible for producing this disturbance may yet
spawn additional major flares and Earthward-directed CME's in the days ahead.
A copy of the official Middle Latitude Auroral Activity Warning is
appended below for your convenience.
MIDDLE LATITUDE AURORAL ACTIVITY WARNING
Issued: 05:05 UTC on 14 May 2005
Solar Terrestrial Dispatch
www.spacew.com
VALID BEGINNING AT: 00:00 UTC 15 MAY 2005
VALID UNTIL: 23:00 UTC (6 pm EST) ON 16 MAY
HIGH RISK PERIOD: 15 MAY (UTC DAYS)
MODERATE RISK PERIOD: 15-16 MAY
PREDICTED ACTIVITY INDICES: 14, 70, 30, 12 (14 - 17 MAY)
POTENTIAL MAGNITUDE OF MIDDLE LATITUDE AURORAL ACTIVITY: MODERATE TO HIGH
POTENTIAL DURATION OF THIS ACTIVITY: MAIN BELT = 12-18 HOURS
MINOR BELT = 18-24 HOURS
ESTIMATED OPTIMUM OBSERVING CONDITIONS: NEAR OR PRIOR TO LOCAL MIDNIGHT
EXPECTED LUNAR INTERFERENCE: LOW
OVERALL OPPORTUNITY FOR OBSERVATIONS FROM MIDDLE LATITUDES: 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 IF SUITABLE STORM CONDITIONS MATERIALIZE DURING DARKNESS.
SYNOPSIS...
A major class M8.0 solar flare on 13 May has been associated with a
coronal mass ejection that appears to be strongly Earthward-directed. A major
geomagnetic and auroral storm is expected to materialize on 15 May when the
CME impacts the Earth. Periods of moderate to strong auroral storm conditions
could be observed with this disturbance. Many middle latitude observations of
activity should be possible after the disturbance arrives. Impact is expected
sometime during the early to mid UTC hours of 15 May and the disturbance
should persist well into 16 May. For North American observers, the first
opportunity to observe activity may come as early as the very early morning
hours (pre-dawn) of 15 May. The next (slightly less favorable) opportunity
will be on the evening of 15 May, although depending on when the disturbance
arrives, storm conditions may be on the decline by the time darkness falls
over North America. Observers are encouraged to watch for activity. As we
approach the solar minimum, these opportunities to observe the "northern
lights" will diminish in frequency. This disturbance may have the potential
to produce fairly vigorous auroral storming for brief periods of time.
This warning will remain valid through 24:00 UTC (6 pm EDT) on
16 May. 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
---------------------------------
Yahoo! Mail Mobile
Take Yahoo! Mail with you! Check email on your mobile phone.
Other related posts:
