[Prev][Next][Index][Thread]

(meteorobs) Aurora Alert

Just had the following forwarded to me by a friend, thought it might be useful for those observers planning 
meteor sessions in the next 36 hours or so.....

- Cathy
   Ottawa, Canada


Date: 	Wed, 23 Oct 1996 16:37:42 -0400
Subject: [APML]: propagation / aurora Alert
To: astro-photo@nightskydot com
Sender: owner-astro-photo@nightskydot com

LBO ALERT: to all users.

A geomagnetic storm is in progress, and there is a possibility for some
aurora watching tonite for northern US.  Excerpts from bulletins follow.

                        MINOR GEOMAGNETIC STORM ALERT

                        ISSUED: 03:50 UT, 23 OCTOBER

      POTENTIAL DURATION OF GEOMAGNETIC STORM:  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:  4 - 5
        EXPECTED DOMINATING HIGH LATITUDE K-INDEX:  5

   POTENTIAL FOR LOW LATITUDE HF DEGRADATION:  MODERATE
        POTENTIAL SEVERITY OF HF DEGRADATION:  MINOR
          EXPECTED HF PROPAGATION CONDITIONS:  MOSTLY GOOD TO OCCAS.
FAIR

POTENTIAL FOR MIDDLE LATITUDE HF DEGRADATION:  HIGH
        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:  MAJOR
          EXPECTED HF PROPAGATION CONDITIONS:  VERY POOR TO USELESS

SUSPECTED SOURCE OF OBSERVED/EXPECTED ACTIVITY:
     A well placed solar coronal hole.


ESTIMATED FORECAST PEAK PLANETARY 24-HOUR A-INDEX DURING STORM: 40 - 50

COMMENTS:
 
     A strong burst of geomagnetic storming over the last six hours
has pushed middle latitude geomagnetic indices above the minor storm
threshold at 03:00 UTC.  This activity is the result of a high-speed
solar wind stream pushing past the Earth from a well placed solar
coronal hole.  It has not yet been confirmed whether a recent
confirmed coronal mass ejection may be contributing to the activity.
 
     Major to severe geomagnetic storming has been reported over many
high latitude regions.  Additional minor to severe storming is
expected throughout the local night sectors over the next 24 to 36
hours.
 
AURORAL ACTIVITY MAY BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...
 
	NORTHERN OREGON TO IDAHO TO NORTHEASTERN WYOMING TO SOUTH
	DAKOTA TO NORTHERN IOWA TO NORTHERN ILLINOIS TO NORTHERN
	INDIANA TO OHIO
TO
        PENNSYLVANIA TO NEW JERSEY.
 
ACTIVITY MAY ALSO BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...

        NORTHERN FRANCE TO BELGIUM TO GERMANY TO POLAND TO NORTHERN
	RUSSIA INCLUDING ALL OF ENGLAND/IRELAND DENMARK, NORWAY,
	SWEDEN, FINLAND AND NEIGHBORING REGIONS.  SOUTHERN AUSTRALIA
	AND NEW ZEALAND SHOULD 
ALSO
        SPOT PERIODS OF ACTIVITY.
 
SYNOPSIS...
  
Auroral activity has intensified considerably over the last 6 hours,
much more than was expected.  The source of this activity is a
recurrent disturbance attributed to a solar coronal hole.  The phase
of the moon will play a limiting factor for observers.  Dark sky sites
will enhance views, but some of the activity will almost certainly be
drowned out by the light of the moon until it reaches the lower
horizon in the morning hours.  If activity continues at current
intensities, activity should become visible over fairly wide areas of
the middle latitudes.
 
Activity is already being reported from numerous upper-middle latitude
stations.  It appears the auroral zones are expanding equatorward,
which should enhance the visibility of activity from central middle
latitude regions.  Activity is not expected to be maintained at this
level of intensity for more than about 12 hours, if that.  However,
sporadic bursts of minor auroral storming are expected over the next
couple of days. The next 12 hours will probably provide the best views
of activity for those who are favorably situated.