:Product: 20040412RSGA.txt
:Issued: 2004 Apr 12 2200 UTC
# Prepared jointly by the U.S. Dept. of Commerce, NOAA,
# Space Environment Center and the U.S. Air Force.
#
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 103 Issued at 2200Z on 12 Apr 2004
IA.  Analysis of Solar Active Regions and Activity from  11/2100Z
to 12/2100Z:  Solar activity was at low levels.  Region 588 (S15W68)
produced multiple C-class flares today.  The largest was a C2/Sf
event that occurred at 12/0225Z.  This region remains a reverse
polarity beta magnetic configuration.  Updated LASCO imagery
indicates two separate occurrences of CME activity yesterday.  A
partial halo CME was observed in response to the C9/Sf event
(erupted at 11/0419Z) that indicates potential for a glancing blow
from the likeliness of a resulting shock passage.  The second, a
full halo CME first seen in C2 at 11/1154Z, was determined to be
backsided.  New Region 591 (S15E01) was numbered today.
IB.  Solar Activity Forecast:  Solar activity is expected to be at
very low to low levels.
IIA.  Geophysical Activity Summary 11/2100Z to 12/2100Z:
The geomagnetic field was at quiet to active levels.  A shock passage
was observed at the ACE spacecraft at approximately 12/1730Z and it
is believed to be in response to the partial halo CME that was
associated with the C2 flare that occurred on 09/2040Z.  Once again,
the IMF Bz remained predominantly northward and the geomagnetic
response was weak.  Solar wind speeds peaked at near 540 km/s
shortly after the shock passage and has decreased to approximately
440 km/s at the time of this writing.  The greater than 10 MeV
proton event that began at 11/1135Z, peaked at 35 pfu at 11/1845Z,
and ended at 12/0405Z.  The greater than 2 MeV electron flux at
geosynchronous orbit reached high levels today.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to range from quiet to active levels.  Minor storm
conditions may occur on 13 April in response to a shock passage from
yesterdays C9 flare and the associated partial halo CME.  14 and 15
April should see a return to predominantly unsettled levels with the
potential for active conditions, mostly in high latitude nighttime
sectors.
III.  Event Probabilities 13 Apr-15 Apr
Class M    15/15/10
Class X    01/01/01
Proton     10/05/01
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           12 Apr 091
Predicted   13 Apr-15 Apr  095/100/105
90 Day Mean        12 Apr 109
V.  Geomagnetic A Indices
Observed Afr/Ap 11 Apr  006/008
Estimated Afr/Ap 12 Apr  012/012
Predicted Afr/Ap 13 Apr-15 Apr  015/020-012/015-010/012
VI.  Geomagnetic Activity Probabilities 13 Apr-15 Apr
A.  Middle Latitudes
Active                30/25/20
Minor storm           15/10/10
Major-severe storm    10/05/05
B.  High Latitudes
Active                40/30/20
Minor storm           20/15/10
Major-severe storm    10/10/05