[ncnculture] Space Weather: PRESTO ALERT

Jeff Gordon jeff.gordon at wellnow.com
Mon Nov 8 18:48:13 UTC 2004


----- Forwarded message from Solar Influences Data analysis Center <sidc at oma.be> -----

From: Solar Influences Data analysis Center <sidc at oma.be>
Reply-To: sidctech at oma.be
Subject: PRESTO ALERT

:Issued: 2004 Nov 08 0909 UTC
:Product: documentation at http://sidc.oma.be/products/presto
#------------------------------------------------------------------------------#
# FAST WARNING 'PRESTO' MESSAGE  from the SIDC (RWC-Belgium)                   #
#------------------------------------------------------------------------------#

A severe geomagnetic storm (Kp=8-9) is in progress since 07/11 21:00
UT. This major event was triggered by a shock in the solar wind
recorded by the ACE spacecraft at 07/11 17:59UT. The solar wind speed
jumped then to 650km/s, but it is only later that the interplanetary
magnetic field took a southward orientation in two steps: Bz=-20nT at
19:30UT and Bz=-50nT at 22:30UT.

With two smaller shocks recorded around 7/11 02:22 and 10:22UT, this
major disturbance is associated with the multiple halo CMEs launched in
active region 61 (NOAA696) on Nov. 4 and 5.

Although the solar wind speed has increased further to 700 km/s, Bz has
now declined to -15nT, and ground-based magnetograms show a slight
decline in the geomagnetic activity, which is currently still at major
storm levels.

Those storm conditions are expected to regain strength in the coming
hours and at least for the next 2 days, as new disturbances arrive.
Indeed, the halo CME recorded by LASCO C3 on Nov. 6 at 02:15UT may
still hit the Earth later today.

Moreover, an X2.0 flare occured in active ragion 61 (NOAA696)
yesterday, on Nov. 7 15:42UT. Based on the most recent imagery, this
flare has spawned a new semi-halo CME that is expected to lead to a new
geomagnetic storm on Nov.10. As all current events are produced by the
same region, they are expected to share the same magnetic polarity.
Therefore, upcoming events are expected, like today, to carry a
southward-oriented IMF and thus to be strongly geoeffective.

A >10MeV proton event started on Nov.7 at 19:00UT and reached a peak
value of 800pfe at 23:25UT. The >10MeV proton flux is now declining but
still above event threshold.


#------------------------------------------------------------------------------#
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# Royal Observatory of Belgium                                                 #
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----- End forwarded message -----

-- 

 -- Jeff --   <http://www.wellnow.com>

 "There's nothing left in the world to prove.  All that's worth doing
  is to love one another, using whatever means are available to serve."



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