:Product: 20040410RSGA.txt
:Issued: 2004 Apr 10 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 101 Issued at 2200Z on 10 Apr 2004
IA.  Analysis of Solar Active Regions and Activity from  09/2100Z
to 10/2100Z:  Solar activity was very low. Region 588 (S15W38)
contains the only sunspots on the visible disk. This region
maintains a reverse polarity beta magnetic configuration, but has
been quiet since producing a C2 flare and CME at 09/2040Z. No other
significant activity or changes were observed.
IB.  Solar Activity Forecast:  Solar activity is expected to be low
to very low. Isolated C-class flares are possible from Region 588.
IIA.  Geophysical Activity Summary 09/2100Z to 10/2100Z:
The geomagnetic field was quiet to unsettled. Solar wind speed was in
gradual decline following yesterday's CME impact. Speed declined
from a peak near 570 km/s at 09/0505Z to near 400 km/s late in the
period. A sharp discontinuity in solar wind plasma and IMF
measurements occurred at 10/1925Z. This was likely the
interplanetary shock associated with the C7 flare and CME on 08
April. Solar wind speed following the shock ranged from 500 to 540
km/s, but the IMF BZ was mostly northward. The greater than 2 MeV
electron flux at geosynchronous orbit reached high levels again this
period.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be quiet to active. Occasional active periods are
expected on 11 April following today's CME arrival. Updated LASCO
imagery reveal another Earth-directed CME associated with
yesterday's C2 flare at 09/2040Z. A geomagnetic response is likely
on 12 April, but the disturbance should be limited to occasional
active periods. Mostly quiet to unsettled conditions are expected on
13 April.
III.  Event Probabilities 11 Apr-13 Apr
Class M    05/10/10
Class X    01/01/01
Proton     01/01/01
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           10 Apr 088
Predicted   11 Apr-13 Apr  090/095/100
90 Day Mean        10 Apr 109
V.  Geomagnetic A Indices
Observed Afr/Ap 09 Apr  011/016
Estimated Afr/Ap 10 Apr  015/012
Predicted Afr/Ap 11 Apr-13 Apr  020/020-010/015-005/010
VI.  Geomagnetic Activity Probabilities 11 Apr-13 Apr
A.  Middle Latitudes
Active                40/30/15
Minor storm           25/10/05
Major-severe storm    15/01/01
B.  High Latitudes
Active                45/35/25
Minor storm           35/15/10
Major-severe storm    20/05/01