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MIDDLE LATITUDE AURORAL ACTIVITY WARNING
UPDATED: 11:45 UTC, 10 APRIL 2001
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*** POTENTIAL FOR MODERATE TO HIGH ACTIVITY EXISTS ***
MAJOR X2.2/3B SOLAR FLARE AND CME PROMPTS ADJUSTMENT TO FORECAST
VALID BEGINNING AT:
21:00 UTC ON 10 APRIL
VALID UNTIL: 19:00 UTC ON 13 APRIL
HIGH RISK PERIOD: 11
- 12 APRIL (UTC DAYS)
MODERATE RISK PERIOD: 11 - 13 APRIL
PREDICTED ACTIVITY INDICES: 12, 60, 50, 15 (10 APRIL - 13 APRIL)
POTENTIAL MAGNITUDE OF MIDDLE LATITUDE AURORAL ACTIVITY: MODERATE TO HIGH
POTENTIAL DURATION OF THIS ACTIVITY: MAIN BELT = 18 TO 24 HOURS
MINOR BELT = 24 TO 36 HOURS
ESTIMATED OPTIMUM OBSERVING CONDITIONS: PRIOR TO AND NEAR LOCAL MIDNIGHT
EXPECTED LUNAR INTERFERENCE: NONE PRIOR TO MIDNIGHT, HIGH AFTER MOONRISE
OVERALL OPPORTUNITY FOR OBSERVATIONS FROM MIDDLE LATITUDES: FAIR TO GOOD
AURORAL ACTIVITY *MAY* BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...
NORTHERN TO POSSIBLY CENTRAL CALIFORNIA TO NEVADA TO NORTHERN ARIZONA TO
NEW MEXICO TO NORTHERN TEXAS TO OKLAHOMA TO SOUTHERN ARKANSAS TO
MISSISSIPPI TO ALABAMA TO GEORGIA TO SOUTH CAROLINA (*IF* AND *ONLY IF*
FAVORABLE SOLAR WIND CONDITIONS DEVELOP OVER NORTH AMERICA PRIOR TO
MOONRISE). A MORE REALISTIC EXPECTATION MAY BE A LINE ROUGHLY NORTH OF
OREGON TO SOUTHERN IDAHO TO SOUTHERN WYOMING TO NEBRASKA TO IOWA TO
ILLINOIS TO INDIANA TO KENTUCKY TO WEST VERGINIA TO CENTRAL VIRGINIA.
ACTIVITY *MAY* ALSO BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...
NORTHERN SPAIN TO SOUTHERN FRANCE TO NORTHERN ITALY TO SLOVENIA TO
NORTHERN CROATIA TO NORTHERN YUGOSLAVIA TO ROMANIA TO SOUTHERN UKRAINE TO
SOUTH-WESTERN RUSSIA APPROXIMATELY NORTH OF A LINE FROM VORONEZH TO
SARANSK TO KAZAN TO PERM AND EAST-CENTRAL RUSSIA (*IF* AND *ONLY IF*
FAVORABLE SOLAR WIND CONDITIONS DEVELOP OVER EUROPE AND RUSSIA PRIOR TO
MOONRISE). A MORE REALISTIC EXPECTATION MAY BE A LINE ROUGHLY NORTH OF
NORTHERN FRANCE TO CENTRAL GERMANY TO SOUTH-CENTRAL POLAND TO SOUTHERN
BELARUS TO SOUTH OF MOSCOW TO KIROV TO OTHER NORTHERN TO NORTH-CENTRAL
RUSSIAN REGIONS.
SYNOPSIS...
Addendum:
A major class X2.2/3B solar flare was observed at 05:27 UTC on 10
April. Although there was no complementary SOHO data to analyze
at the time of this addendum, observed features suggest this event
may have been associated with a halo CME travelling at a velocity
up to perhaps twice the velocity of the CME observed on 09 April. If
this holds true, a major to severe auroral storm may develop during
the mid to late UTC hours of 11 April following the arrival of this
second major disturbance (sometime near or after 06:00 to 15:00 UTC on
11 April, or 2 am to 11 am EDT on 11 April). These are preliminary
times and may be adjusted when more data becomes available. Major to
severe auroral storming is still contingent upon favorable solar wind
conditions behind the shock front of the disturbance as well as
observing the intense phase of activity prior to moonrise.
In addition to the above,
a heavily Earth-directed and fairly high
velocity coronal mass ejection was observed erupting from the Sun in
association with a major class M7.9 solar x-ray flare at 15:34 UTC on 09
April.
Impact of this disturbance
is expected to occur sometime during the
early UTC day of 11 April followed some hours later by the potentially larger
impact of the X-class flare associated CME.
Observers are encouraged
to watch the skies during the nights of 11 and
12 April for possible activity. Moonrise occurs near local midnight over most
regions on these dates. As a result, optimal observing conditions will occur
after the sun sets and before the moon rises. The near-full phase of the
rising moon will heavily drown out the fainter signatures of auroral
activity.
Additional Earth-directed
coronal mass ejections are possible over the
next several days.
This warning will remain
in effect until 19:00 UTC on 13 April. It
will then be updated or allowed to expire.
For Real-Time News and Discussions with Experienced Aurora Photographers:
and join the #aurora channel (type /join #aurora)
WE HAVE A DISCUSSION FORUM FOR AURORA ENTHUSIASTS AVAILABLE AT:
http://www.spacew.com/aurora/forum.html
PLEASE REPORT OBSERVATIONS OF AURORAL ACTIVITY TO:
http://solar.spacew.com/www/auroras.html
* OR *
Use the STD AURORA MONITOR Software to monitor conditions and
report sightings. It is available at:
A Special Space Weather Prediction Class has been Scheduled for
27 April. Those interested in taking this class should visit:
http://www.spacew.com/www/course.html
** End of Warning **