:Product: 20020410RSGA.txt
:Issued: 2002 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 100 Issued at 2200Z on 10 Apr 2002
IA.  Analysis of Solar Active Regions and Activity from  09/2100Z
to 10/2100Z:  Solar activity was at high levels.  An M8.2/1N flare
occurred at 10/1231 UTC from Region 9893(N19W14) characterized by
parallel ribbons and multiple eruptive centers.  Associated with
this flare was a Type II radio burst (702 km/s) and a partial halo
CME observed from SOHO/LASCO imagery.  Region 9893 has begun to
decay and has simplified to a beta-gamma magnetic configuration.
Region 9899 (N18E22) has increased in magnetic complexity to a
beta-gamma spot and produced an M1.6/1n flare at 10/1907 UTC.
Region 9901(N20W02) has shown growth in spot count and magnetic
complexity.  Region 9904 (S16W21) has developed a small delta
configuration in the leader spot.  Region 9905 (S17E04) was numbered
today.
IB.  Solar Activity Forecast:  Solar activity is expected to be
moderate.  Region 9893 is in decay phase but still has the potential
for a major flare.  Region 9899 and Region 9901 are in a growth
phase and could produce M-class events.
IIA.  Geophysical Activity Summary 09/2100Z to 10/2100Z:
The geomagnetic field was at quiet levels for most of the day with
one period of unsettled conditions from 15-18Z.  The lingering
effects of the high speed stream appear to be ending.  Greater than
2 MeV electrons have returned to near background levels after three
days of enhancement.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be quiet to active.  There is a chance of increased
geomagnetic activity late on day two due to a CME shock passage.  On
day three of the forecast period another CME shock is expected (from
the M8/1N flare on 10/1231 UTC) and geomagnetic activity is expected
to reach unsettled to active conditions.  There is a slight chance
of isolated minor storm levels especially at high latitudes.
III.  Event Probabilities 11 Apr-13 Apr
Class M    60/60/60
Class X    10/10/10
Proton     05/05/05
PCAF       yellow
IV.  Penticton 10.7 cm Flux
Observed           10 Apr 194
Predicted   11 Apr-13 Apr  195/190/185
90 Day Mean        10 Apr 203
V.  Geomagnetic A Indices
Observed Afr/Ap 09 Apr  002/006
Estimated Afr/Ap 10 Apr  006/008
Predicted Afr/Ap 11 Apr-13 Apr  004/008-008/010-012/015
VI.  Geomagnetic Activity Probabilities 11 Apr-13 Apr
A.  Middle Latitudes
Active                10/15/20
Minor storm           01/05/10
Major-severe storm    01/01/05
B.  High Latitudes
Active                15/15/20
Minor storm           05/05/10
Major-severe storm    01/01/05