From cdeehr at gi.alaska.edu  Thu Oct 19 09:21:47 2006
From: cdeehr at gi.alaska.edu (Charles Deehr)
Date: Thu Oct 19 09:45:23 2006
Subject: [gse-aa] Auroral Alert
Message-ID: <000001c6f3a3$11c46420$ec1be589@Forcastle>

The coronal hole on the sun that that has produced active aurorae for at
least 4 solar rotations has come into position again.  The high speed stream
should intercept Earth by midnight Greenwich Time on the 19th.  If it
produces the same level of activity this time as in the previous rotations,
we should see at least 6 hours of planetary magnetic disturbance above 4
during the night of the 19th in North America, the 20th in eastern Russia,
and New Zealand, Tasmania.

The planetary magnetic disturbance index Kp>4 means displays are visible in
all of Canada, Alaska, and Scandinavia and from the northern tier of the
United States.  See the relation of aurora to Kp under "Aurora viewing" at:
http://sec.noaa.gov/pmap/index.html 
 
Aurora watchers should monitor the one hour prediction map at the aurora
forecast website:
http://www.gedds.alaska.edu/AuroraForecast/ click on One Hour Forecast.
It will show the prediction of auroral occurrence one hour in advance. 

If the disturbance is delayed relative to our prediction, (as it has been
for the last 5 solar rotations) the possibility of the 6 or 9 hour
disturbance period occurring during the local night will move westward.
This means possible displays for watchers in western Russia, southern
Scandinavia, and northern UK on the night of the 20th, or even farther west
for US observers on the night of the 20th. 

Dr. Charles Deehr, Prof. Emer. Phys.     Ph. 907 474 7473 Fax 907 474 7290
email cdeehr@gi.alaska.edu
The Geophysical Institute                     
University of Alaska Fairbanks
903 Koyukuk Ave N             
Fairbanks, Alaska  99775-7320