:Product: 20031019RSGA.txt
:Issued: 2003 Oct 19 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 292 Issued at 2200Z on 19 Oct 2003
IA.  Analysis of Solar Active Regions and Activity from  18/2100Z
to 19/2100Z:  Solar activity was high. Region 484 (N06E54) produced
an X1/1n flare starting at 1629 UTC, with maximum at 1650 UTC and
ending at 1704 UTC. The flare was accompanied by strong radio
bursts, a type II radio sweep, and was associated with a coronal
mass ejection. The CME was observed in LASCO-C2 off the northeast
limb beginning at 1708 UTC with a plane-of-sky speed of about 500
km/s. Region 484 also produced two M1 flares: one at 0626 UTC, the
other at 1926 UTC. The region also produced a C6/1f at 18/2218 UTC
that was associated with a CME off the southeast limb around 18/2230
UTC. Neither of these CMEs appear to have any earthward directed
component. Region 484 grew dramatically during the past 24 hours
from 240 millionths at the start of the day to just over 1000
millionths by forecast issue time. This remarkable emergence of new
flux led to the formation of a strong delta configuration across a
northeast-to-southwest polarity inversion line which was also the
location of the most intense emission from the X1 flare event.
IB.  Solar Activity Forecast:  Solar activity is expected to be
predominantly moderate for the next three days, with Region 484 as
the dominant source of activity. There is a chance for more major
flare activity from Region 484, especially if it continues to grow.
IIA.  Geophysical Activity Summary 18/2100Z to 19/2100Z:
The geomagnetic field ranged from unsettled to minor storm levels
during the past 24 hours. A jump in solar wind velocity from 540
km/s to 600 km/s was observed around 2200 UTC. However, the solar
wind signatures continue to be consistent with a high-speed coronal
driven wind stream. The Bz component of the interplanetary magnetic
field continues to oscillate around an average value of about -5 nT.
The greater than 2 MeV electron fluxes continue to be at high
levels.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be unsettled to active for the next 24 hours, increasing
to mostly active with minor storm periods on the second day, and
returning back to unsettled to active for the third day. The
increase on day two is expected as a response to the particular
morphology of a coronal hole rotating across the western part of the
solar disk. A glancing blow from the partial-halo CME of 18/1554 UTC
may also contribute to activity on day two.
III.  Event Probabilities 20 Oct-22 Oct
Class M    70/70/70
Class X    15/15/15
Proton     10/10/10
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           19 Oct 120
Predicted   20 Oct-22 Oct  125/130/130
90 Day Mean        19 Oct 115
V.  Geomagnetic A Indices
Observed Afr/Ap 18 Oct  015/027
Estimated Afr/Ap 19 Oct  015/025
Predicted Afr/Ap 20 Oct-22 Oct  012/020-020/030-015/025
VI.  Geomagnetic Activity Probabilities 20 Oct-22 Oct
A.  Middle Latitudes
Active                30/35/35
Minor storm           25/30/30
Major-severe storm    10/20/10
B.  High Latitudes
Active                35/25/35
Minor storm           30/40/35
Major-severe storm    15/25/15