:Product: 20020317RSGA.txt
:Issued: 2002 Mar 17 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 076 Issued at 2200Z on 17 Mar 2002
IA.  Analysis of Solar Active Regions and Activity from  16/2100Z
to 17/2100Z:  Solar activity was moderate during the past 24 hours.
Region 9871 (S18E20) produced today's biggest event, an impulsive
M4/Sf at 1931 UTC. The region appears to be growing slowly. An
additional M-class event occurred: an M1 at 1019 UTC for which there
was no optical report. Region 9866 (S09W33) is decaying gradually,
but is still the largest region on the disk. Retrospective analysis
of the CME that occurred around 15/2310 UTC shows a full halo event
with an estimated plane-of-sky speed somewhere in the 750-850 km/s
range. New Region 9873 (S17W09) emerged near the middle of the solar
disk during the past 24 hours.
IB.  Solar Activity Forecast:  Solar activity is expected to be
moderate during the next three days, with Regions 9866 and 9871
being the most likely sources.
IIA.  Geophysical Activity Summary 16/2100Z to 17/2100Z:
The geomagnetic field was quiet during the past 24 hours. The greater
than 10 MeV protons began to rise at the very end of the UT day
yesterday and crossed event threshold at 17/0820 UTC. The fluxes
reached a maximum of 13 PFU at 17/0850 UTC. The fluxes dropped below
threshold at 17/1230 UTC, but have been fluctuating and have been on
the increase since around 1500 UTC. It seems probable that the
current slow climb is related to the approach of an interplanetary
shock.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to reach active to minor storm levels tomorrow in response
to the halo CME event of 15/2310 UTC. A decrease to active is
expected on the second day and  a further decline to unsettled is
expected by the third day. The current trend of the 10 MeV protons
and the likely arrival of a shock in the next 12 hours all suggest
that the proton fluxes should once again cross threshold.
III.  Event Probabilities 18 Mar-20 Mar
Class M    50/50/50
Class X    05/05/05
Proton     50/05/05
PCAF       yellow
IV.  Penticton 10.7 cm Flux
Observed           17 Mar 184
Predicted   18 Mar-20 Mar  190/195/190
90 Day Mean        17 Mar 215
V.  Geomagnetic A Indices
Observed Afr/Ap 16 Mar  005/005
Estimated Afr/Ap 17 Mar  005/005
Predicted Afr/Ap 18 Mar-20 Mar  030/030-020/020-010/010
VI.  Geomagnetic Activity Probabilities 18 Mar-20 Mar
A.  Middle Latitudes
Active                20/25/25
Minor storm           25/20/15
Major-severe storm    20/15/05
B.  High Latitudes
Active                20/25/30
Minor storm           25/20/15
Major-severe storm    25/20/10