MIDDLE LATITUDE AURORAL ACTIVITY WATCH

[Ulrich Rieth]

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MIDDLE LATITUDE AURORAL ACTIVITY WATCH

ISSUED: 15:30 UTC, 20 OCTOBER 2001

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** NOTE: A NEW VERSION OF THE STD AURORA MONITOR HAS BEEN RELEASED **

Details at: http://www.spacew.com/aurora

VALID BEGINNING AT: 18:00 UTC (2 pm EDT) ON 21 OCTOBER
VALID UNTIL: 19:00 UTC (3 pm EDT) ON 24 OCTOBER

HIGH RISK PERIOD: 22 OCT - 23 OCTOBER (UTC DAYS)
MODERATE RISK PERIOD: 21 OCT - 24 OCTOBER

PREDICTED ACTIVITY INDICES: 12, 15, 35, 30 (20 OCT - 23 OCT)

POTENTIAL MAGNITUDE OF MIDDLE LATITUDE AURORAL ACTIVITY: MODERATE

POTENTIAL DURATION OF THIS ACTIVITY: MAIN BELT = 24 TO 36 HOURS

MINOR BELT = 36 TO 48 HOURS

ESTIMATED OPTIMUM OBSERVING CONDITIONS: NEAR LOCAL MIDNIGHT

EXPECTED LUNAR INTERFERENCE: NONE

OVERALL OPPORTUNITY FOR OBSERVATIONS FROM MIDDLE LATITUDES: FAIR

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

WASHINGTON STATE TO IDAHO TO SOUTHERN MONTANA TO SOUTH DAKOTA TO MINNESOTA

TO SOUTHERN WISCONSIN TO SOUTHERN MICHIGAN TO NORTHERN OHIO TO

PENNSYLVANIA TO NEW JERSEY.

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

UNITED KINGDOM TO EXTREME NORTHERN NETHERLANDS TO NORTHERN GERMANY TO

NORTHERN POLAND TO LITHUANIA TO LATVIA AND ESTONIA TO NORTHERN RUSSIA.

SOUTHERN REGIONS OF NEW ZEALAND MAY ALSO BE ABLE TO SPOT PERIODS OF

ACTIVITY.

SYNOPSIS...

Two X-class solar flares were observed on 19 October that were
associated with confirmed Earth-directed coronal mass ejections. The first of
these disturbances is expected to impact the Earth's magnetosphere late in
the UTC day of 21 October or early on 22 October (late afternoon/early
evening hours of 21 October for North Americans). Our estimates are centered
around an impact time of near 03:00 UTC on 22 October (11 pm EDT on *21*
October) give or take several hours. Auroral activity could intensify to
active or perhaps even sporadic minor storm levels capable of being observed
across many dark-sky middle latitude regions.

The second disturbance is expected to arrive later on 22 October and
will have the effect of prolonging auroral activity through 23 October.
Barring additional possible Earthward directed coronal mass ejections, the
activity should then begin to subside by the early part of the UTC day of
24 October.

This watch will remain in effect until 19:00 UTC (3 pm EDT) on 24
October. It will then be updated or allowed to expire. For updated
information, visit: 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:

http://www.spacew.com/aurora

or from Sky & Telescope:

http://store.skypub.com

(search for Aurora)

For Real-Time News and Discussions with Experienced Aurora Enthusiasts:

http://www.spacew.com/irc

and join the #aurora channel (type /join #aurora)

** End of Watch **

[Ulrich Rieth]

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POTENTIAL MAJOR/SEVERE GEOMAGNETIC STORM WARNING

ISSUED: 16:00 UTC, 20 OCTOBER 2001

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(See Appended Comments for Synoptic Information)

VALID BEGINNING AT: 18:00 UTC 22 OCT

VALID UNTIL: 19:00 UTC 24 OCT

HIGH RISK PERIOD: 22 - 23 OCT (UTC days)
MODERATE RISK PERIOD: 21 - 24 OCT

POTENTIAL LOW-MIDDLE LATITUDE STORM INTENSITY: MINOR

POTENTIAL HIGH LATITUDE STORM INTENSITY: MINOR - MAJOR

POTENTIAL DURATION OF GEOMAGNETIC STORM: APPROX 48 HOURS

DURATION OF MAIN BELT OF ACTIVITY: 24 TO 36 HOURS

POTENTIAL PEAK LOW-MIDDLE LATITUDE K-INDEX VALUES: 6

POTENTIAL PEAK HIGH LATITUDE K-INDEX VALUES: 7

EXPECTED DOMINATING LOW-MIDDLE LATITUDE K-INDEX: 5 - 6

EXPECTED DOMINATING HIGH LATITUDE K-INDEX: 5 - 6

POTENTIAL FOR LOW LATITUDE HF DEGRADATION: LOW

POTENTIAL SEVERITY OF HF DEGRADATION: MINOR

EXPECTED HF PROPAGATION CONDITIONS: GOOD

POTENTIAL FOR MIDDLE LATITUDE HF DEGRADATION: MODERATE

POTENTIAL SEVERITY OF HF DEGRADATION: STRONG MINOR

EXPECTED HF PROPAGATION CONDITIONS: FAIR TO POOR

POTENTIAL FOR HIGH LATITUDE HF DEGRADATION: HIGH

POTENTIAL SEVERITY OF HF DEGRADATION: STRONG MINOR TO WEAK MAJOR

EXPECTED HF PROPAGATION CONDITIONS: POOR TO OCCAS. VERY POOR

POTENTIAL RISK FOR GEOSYNCHRONOUS MAGNETOPAUSE CROSSINGS: 40%

SUSPECTED SOURCE OF OBSERVED/EXPECTED ACTIVITY:

A full halo high coronal mass ejection associated with two
energetic major class X1.6 solar flares on 19 October.

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EST. POTENTIAL GEOMAGNETIC IMPACT EST. POTENTIAL IONOSPHERIC IMPACT
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SEVERE STORM : 15 % LOW LATITUDES : MINOR

MAJOR STORM : 30 % MIDDLE LATITUDES : MINOR

MINOR STORM : 40 % HIGH LATITUDES : MINOR-MAJOR

ACTIVE OR LESS : 15 % POLAR LATITUDES : MINOR-MAJOR
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PROBABLE SI ASSOCIATION : 65% ESTIMATED GLOBAL IMPACT: MINOR - MAJOR

ESTIMATED FORECAST PEAK PLANETARY 24-HOUR A-INDEX DURING STORM: 35

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COMMENTS:

None.

** End of Warning **

[Ulrich Rieth]

http://theyr.com/cg/cny/Id96cd/F=js*s*0 ... *de_Berlin

[Peter Kuklok]

...das "MAJOR/SEVERE" aus der Warnung vorher streichen sollen, passt nämlich nicht zum Text. Dürfte noch ein Überbleibsel von der vorherigen Warnung vom 25.9 sein.

Grüße
Peter