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>From: oler@HG.ULeth.CA (CARY OLER)
>Newsgroups: rec.radio.amateur.misc
>Subject: MAJOR GEOMAGNETIC STORM UPDATE - 07 JUNE
>Message-ID: <910606191617.21c027ac@HG.ULeth.CA>
>Date: 7 Jun 91 01:16:17 GMT
>Sender: daemon@ucsd.Edu
>Organization: UCSD Usenet Gateway
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                            GEOMAGNETIC STORM UPDATE

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                               01:00 UT, 07 June

                                 -------------


STORM UPDATE INFORMATION:

     Geomagnetic storming has presently ended.  Generally unsettled to active
conditions have been observed since approximately 06:00 UT on 06 June.
However, geomagnetic storming is expected to redevelope sometime in the UT
day of 07 June.  Activity is expected to become major to severe once again as
yesterdays major class X12+/3B flare begins to have an impact.

     The most disturbed day of the period should be 08 June.  Geomagnetic
activity on that day is expected to be at major to severe storm levels
throughout much of the day.  Planetary A-indices are expected to range
between 60 and 150.  Planetary K-indices of between 5 and 8 are also
possible.  K-indices of 9 will be possible over the northerly middle and high
latitude regions.

     Geomagnetic activity should become more dormant by 10 June, barring
further energetic flaring.  Major flaring is expected to continue from Region
6659 over the next 3 to 7 days at least.  It is maintaining a very potent
optical and magnetic configuration and has maintained its overall size.
White-light flares from this region may be possible.

     HF propagation conditions are still well below normal, although
improvements have been observed lately.  Conditions are expected to become
strongly degraded on 07 and 08 June as geomagnetic storming redevelops.
Polar latitude PCA activity has blacked out radio signals over many high
latitude and polar latitude regions.  Absorption levels are currently running
at values near 2.8 dB (above event thresholds).

     PCA and proton activity are expected to continue over the next several
days.  Protons are currently hovering near 240 pfu at greater than 10 MeV.  A
significant enhancement in protons could occur if another major solar flare
erupts from Region 6659.  This region is continuing to move toward the
central solar meridian and will therefore become increasingly capable of
producing stronger proton impacts.

     VHF propagation conditions have returned to semi-normal over the past 24
hours, although instabilities and some unusual conditions have been reported.
VHF backscatter communications are expected to recur as geomagnetic storming
redevelops on 07 and 08 June.  Significant and widespread VHF backscatter may
exist on these dates (particularly 08 June).

     Low latitude auroral activity is expected to become possible again late
in the evening hours on 07 and possibly 08 June (local time).  The Low
Latitude Auroral Activity Warning is being held over until 08 June.  If the
expected shock fails to arrive by then, the warning will be reassessed.

     The next update will be later this UT day.


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