NOAA SEC Report of Solar-Geophysical Activity 3 Apr 2002
:Product: Report of Solar-Geophysical Activity
:Issued: 2002 Apr 04 2210 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 094 Issued at 2200Z on 04 Apr 2002
IA. Analysis of Solar Active Regions and Activity from 03/2100Z
to 04/2100Z: Solar activity increased to high levels, due to an
impulsive M6.1 flare at 04/1532 UTC, which originated from a source
region behind the southeast limb. The presumed source is old Region
9866 (S09, L=191), which was an active flare producer on its last
rotation, and is expected to rotate back into view within 24 hours.
Other activity included an impulsive M1.4 flare at 04/1048 UTC from
an evident source behind the southwest limb, and a C9.8 flare at
04/0442 UTC from a spotless plage region near S20E58, which was
accompanied by a Type-II radio sweep (estimated velocity = 463 km/s)
and a nearby disappearing filament. The CME activity associated
with these events did not appear Earth-directed in SOHO/LASCO
imagery. Most numbered regions on the visible disk appeared little
changed from yesterday. Minor optical flares were observed in
Regions 9885 (N13W39), 9888 (S12W06), and 9893 (N18E64).
IB. Solar Activity Forecast: Solar activity is expected to be
predominantly low to moderate for the next three days. A chance for
isolated major flare activity exists, in particular with the return
of old Region 9866.
IIA. Geophysical Activity Summary 03/2100Z to 04/2100Z:
The geomagnetic field was quiet to unsettled. At 04/1335 UTC, the
greater than 2 MeV electron flux exceeded event threshold at GOES-8
in geosynchronous orbit (75W). Flux levels remained above 1000 pfu
for the remainder of the period.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be predominantly quiet to unsettled. A chance for some
isolated active periods exists for days two and three of the
forecast period, due to the possibility of some flanking shock
passage effects from the CME events observed earlier today. Greater
than 2 MeV electron flux is expected to persist at moderate to high
levels for the next two to three days.
III. Event Probabilities 05 Apr-07 Apr
Class M 60/60/60
Class X 05/05/05
Proton 05/05/05
PCAF green
IV. Penticton 10.7 cm Flux
Observed 04 Apr 216
Predicted 05 Apr-07 Apr 215/215/210
90 Day Mean 04 Apr 203
V. Geomagnetic A Indices
Observed Afr/Ap 03 Apr 012/013
Estimated Afr/Ap 04 Apr 008/012
Predicted Afr/Ap 05 Apr-07 Apr 008/010-012/012-010/010
VI. Geomagnetic Activity Probabilities 05 Apr-07 Apr
A. Middle Latitudes
Active 10/15/15
Minor storm 05/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 10/20/15
Minor storm 05/05/05
Major-severe storm 01/01/01
