:Product: 20030423RSGA.txt
:Issued: 2003 Apr 23 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 113 Issued at 2200Z on 23 Apr 2003
IA.  Analysis of Solar Active Regions and Activity from  22/2100Z
to 23/2100Z:  Solar activity increased to high levels this period.
Region 338 (N18W32) produced an M5/1n flare at 23/0106Z. Type II
(513 km/s) and Type IV radio sweeps, and a 380 sfu tenflare were
associated with this event. A partial halo CME was also detected on
LASCO imagery. An M2/1f flare also occurred in this region at
23/1556Z. This complex region continues to develop in both size and
magnetic complexity. Region 339 (N16W84) was quite active as it
approaches the west limb. It produced several C-class flares, the
largest being a C5 flare at 23/1213Z. No significant changes were
observed in the remaining active regions. New Region 343 (N06E60)
was numbered today.
IB.  Solar Activity Forecast:  Solar activity is expected to be at
moderate levels. Region 338 maintains potential for further M-class
activity.
IIA.  Geophysical Activity Summary 22/2100Z to 23/2100Z:
The geomagnetic field ranged from quiet to active levels with
isolated minor storm periods at high latitudes. Elevated solar wind
speeds near 500 km/s are responsible for the disturbed periods. The
greater than 2 MeV electrons at geosynchronous orbit reached high
levels again today.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be at unsettled to minor storm levels. Ongoing high
speed coronal hole flow will likely be enhanced by transient flow
over the next three days. Weak impact from the April 22, M2 flare
and CME are possible on day one. There is a higher probability for
CME impacts on days two and three from the M5 and associated CME
that occurred early this period.
III.  Event Probabilities 24 Apr-26 Apr
Class M    40/40/40
Class X    05/05/05
Proton     05/05/05
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           23 Apr 133
Predicted   24 Apr-26 Apr  135/140/145
90 Day Mean        23 Apr 126
V.  Geomagnetic A Indices
Observed Afr/Ap 22 Apr  013/022
Estimated Afr/Ap 23 Apr  015/020
Predicted Afr/Ap 24 Apr-26 Apr  020/020-020/020-015/015
VI.  Geomagnetic Activity Probabilities 24 Apr-26 Apr
A.  Middle Latitudes
Active                30/40/30
Minor storm           20/30/20
Major-severe storm    05/10/05
B.  High Latitudes
Active                40/50/40
Minor storm           30/35/30
Major-severe storm    10/15/10