:Product: 20020518RSGA.txt
:Issued: 2002 May 18 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 138 Issued at 2200Z on 18 May 2002
IA.  Analysis of Solar Active Regions and Activity from  17/2100Z
to 18/2100Z:  Solar activity was low.  Several minor C-class events
were observed through the period.  Region 9957 (N08E47) remains the
largest and most complex region on the disk and maintains its
beta-gamma-delta configuration.  A new region was numbered today as
Region 9960 (N15E74).
IB.  Solar Activity Forecast:  Solar activity is expected to be low
to moderate.  Region 9957 is capable of producing an M-class event
with a chance for an isolated X-class event.
IIA.  Geophysical Activity Summary 17/2100Z to 18/2100Z:
The geomagnetic field was predominately quiet to unsettled.  Active
to minor storm conditions were observed at 18/2100 UTC.  A shock
passed the ACE spacecraft at 18/1919 UTC and created a sudden
impulse of 31 nT on the Boulder magnetometer at 18/2007 UTC.  Solar
wind velocity increased from 381 km/s to 450 km/s.  This shock is
believed related to the full halo CME on 16 May.  The greater than 2
MeV electron flux observed at geosynchronous orbit was at moderate
levels today.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be unsettled to active for 19 May as the current CME
passes.  Quiet to unsettled conditions are expected for 20 and 21
May.  The greater than 2 MeV electron flux is expected to persist at
moderate levels for the next two to three days.
III.  Event Probabilities 19 May-21 May
Class M    75/75/75
Class X    10/10/10
Proton     01/01/01
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           18 May 163
Predicted   19 May-21 May  170/175/180
90 Day Mean        18 May 185
V.  Geomagnetic A Indices
Observed Afr/Ap 17 May  004/010
Estimated Afr/Ap 18 May  010/010
Predicted Afr/Ap 19 May-21 May  020/020-015/015-008/010
VI.  Geomagnetic Activity Probabilities 19 May-21 May
A.  Middle Latitudes
Active                25/20/15
Minor storm           10/10/05
Major-severe storm    05/01/01
B.  High Latitudes
Active                30/25/20
Minor storm           15/10/10
Major-severe storm    05/01/01