:Product: 20020427RSGA.txt
:Issued: 2002 Apr 27 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 117 Issued at 2200Z on 27 Apr 2002
IA.  Analysis of Solar Active Regions and Activity from  26/2100Z
to 27/2100Z:  Solar activity was low. The largest event of the period
was a C4/Sf from Region 9919 (N12E14). Other minor C-class flares
were observed in this Beta region. No significant activity or
changes were noted in the remaining active regions. The filament
eruption observed late in the last period from near S32W12 produced
a large CME, but it does not appear Earthbound. New Region 9926
(N12E26) was numbered today. This spot cluster was formerly grouped
with Region 9919, but magnetograms indicate that it is a separate
region.
IB.  Solar Activity Forecast:  Solar activity is expected to continue
at low levels. Regions 9915 (N11W26) and 9919 will likely produce
C-class flares.
IIA.  Geophysical Activity Summary 26/2100Z to 27/2100Z:
The geomagnetic field was mostly quiet, but became unsettled late in
the period. Solar wind indices on ACE suggest that we are
transitioning into a high speed coronal hole stream. The greater
than 10 MeV protons at geosynchronous orbit remain elevated
following the proton event that began on 21 Apr and ended on the
26th.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be mostly unsettled with isolated active periods at all
latitudes due to high speed coronal hole flow. Minor storm
conditions are expected at high latitudes during local nighttime
hours. Expect quiet to unsettled conditions to return by day three.
III.  Event Probabilities 28 Apr-30 Apr
Class M    25/25/25
Class X    05/05/05
Proton     01/01/01
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           27 Apr 157
Predicted   28 Apr-30 Apr  160/160/165
90 Day Mean        27 Apr 195
V.  Geomagnetic A Indices
Observed Afr/Ap 26 Apr  002/006
Estimated Afr/Ap 27 Apr  007/010
Predicted Afr/Ap 28 Apr-30 Apr  012/012-010/010-008/008
VI.  Geomagnetic Activity Probabilities 28 Apr-30 Apr
A.  Middle Latitudes
Active                35/35/30
Minor storm           15/15/10
Major-severe storm    05/05/01
B.  High Latitudes
Active                45/45/35
Minor storm           25/25/15
Major-severe storm    10/10/05