:Product: 20020527RSGA.txt
:Issued: 2002 May 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 147 Issued at 2200Z on 27 May 2002
IA.  Analysis of Solar Active Regions and Activity from  26/2100Z
to 27/2100Z:  Solar activity increased to moderate levels. Region
9957 (N10W73) produced an M2/2f flare at 27/1810 UTC associated with
minor discrete radio emission. Gradual decay may have continued in
this region, but it was difficult to tell given limb foreshortening
effects. However, it appeared that a weak delta persisted within its
northern cluster of spots. Region 9961 (S22W30) produced isolated
subflares as it continued to decay. Region 9970 (N05E41) appeared to
stabilize as a simply-structured D-type spot group. Active surging
and subflare activity was observed on the southeast limb near SE17.
This limb activity may indicate the active return of old Region 9934
(S16, L = 211). A filament erupted from the northeast quadrant
around midday. The eruption was associated with C2 X-ray event and a
CME off the northeast limb. The CME did not appear to be Earth
directed.
IB.  Solar Activity Forecast:  Solar activity is expected to be low
to moderate. There is a fair chance for an isolated M-class flare
during the period. There is a slight chance for a major flare as
well.
IIA.  Geophysical Activity Summary 26/2100Z to 27/2100Z:
Geomagnetic field activity increased to quiet to active levels with
minor storm conditions observed at some high latitude stations. This
activity was likely due to coronal hole effects. ACE solar wind data
indicated a gradual rise in velocities during the period with peak
velocities in the 700 to 800 km/sec range.
IIB.  Geophysical Activity Forecast:  Quiet to active conditions are
expected during the first half of the period. Quiet to unsettled
conditions are expected during the remainder of the period. There is
a slight chance for a proton event until 29 May.
III.  Event Probabilities 28 May-30 May
Class M    40/40/40
Class X    05/05/01
Proton     05/05/01
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           27 May 187
Predicted   28 May-30 May  180/180/180
90 Day Mean        27 May 183
V.  Geomagnetic A Indices
Observed Afr/Ap 26 May  009/010
Estimated Afr/Ap 27 May  017/025
Predicted Afr/Ap 28 May-30 May  012/012-008/008-008/008
VI.  Geomagnetic Activity Probabilities 28 May-30 May
A.  Middle Latitudes
Active                35/30/25
Minor storm           15/10/10
Major-severe storm    01/01/01
B.  High Latitudes
Active                40/35/30
Minor storm           20/12/12
Major-severe storm    01/01/01