[gse-aa] Auroral Alert

[Charles Deehr]

There was an M class solar flare on the 12th of September.  Murray Dryer
predicted on Sunday that the shock would arrive early on the 15th.  The
data from the CME was not available until Monday, so the initial
velocity was low in our model.  Therefore, the shock arrived 24 hours
early and the storm is in progress now.  

We cannot predict which way the interplanetary field will turn after the
initial shock behaviour, which appears now to be negative/positive.
Following this, the arrival of the magnetic cloud usually determines how
extensive the auroral activity will be.  We should know by early on the
14th UT.  If it turns negative, there will be auroral activity over
Europe early on the 14th, and over the USA on the evening of the 13th.
This does not appear to be a large disturbance, however, and we should
not expect the aurora south of Scandinavia, or the middle of the USA. 

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