:Product: Weekly Highlights and Forecasts
:Issued: 2003 Sep 30 2212 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Environment Center
# Product description and SEC contact on the Web
# http://www.sec.noaa.gov/weekly.html
#
#                Weekly Highlights and Forecasts
#
Highlights of Solar and Geomagnetic Activity
22 - 28 September 2003

Solar activity ranged from very low to low levels.  Activity was at
low levels for the entire period except the first day, 22 September
when it was at very low levels.  Region 464 (N04, L=356, class/area
Fki/610 on 26 September) was a large, moderately complex region that
developed a beta-gamma configuration on 22 September and maintained
this configuration throughout the period.  The majority of activity
during the period was from Region 464.  On 24 September, Region 464
produced numerous minor C-class flares including a C5/1f flare at
0717 UTC.  This region also produced the largest event of the
period, a long duration C6/Sf flare on 28 September at 1558 UTC.  A
20-degree filament near S19W23 erupted off the disk on 24 September
with a rather faint CME observed on LASCO imagery following the
eruption.

Solar wind data were available from the NASA Advanced Composition
Explorer (ACE) spacecraft for most of the summary period.  The
period began with solar wind speed near 600 km/s due to a coronal
hole high speed flow.  On 23 September, the high speed flow was in
decline as yet another coronal hole high speed flow rotated into a
geoeffective position.  Wind speed increased on 24 September and
reached a peak near 775 km/s on 25 September.  The second high speed
flow was in steady decline from 26-28 September and solar wind speed
at the close of the period was near 375 km/s.  The Bz component of
the interplanetary magnetic field fluctuated mostly between +/- 6nT
during the two high speed flows. Peak fluctuations reached –9nT on
24 September.

There were no greater than 10 MeV proton events at geosynchronous
orbit during the period.

The greater than 2 MeV electron flux at geosynchronous orbit reached
high levels everyday during the period (22-28 September).

Geomagnetic activity ranged from quiet to minor storm levels.  The
period began at quiet to occasionally active levels on 22-23
September.  Geomagnetic activity increased on 24-25 September as a
coronal hole rotated into geoeffective position producing mostly
unsettled to minor storm levels.  As the coronal hole high speed
flow began to wane on 26 September activity was at unsettled to
active levels.  Activity form the remainder of the period, 27-28
September was at quiet to unsettled levels.

Forecast of Solar and Geomagnetic Activity
01 - 27 October 2003

Solar activity is expected to range from very low to low levels with
a chance of isolated M-class events.  Region 464 has the potential
for isolated M-class activity early in the period before it rotates
beyond the west limb on 03 October.  Region 471 rotated onto the
visible disk on 30 September and is most likely old Region 456 (S08,
L=222), which was quite active as it rotated beyond the west limb on
its last rotation.  Region 471 may keep activity levels somewhat
enhanced.

No greater than 10 MeV proton events at geosynchronous orbit are
expected during the period.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to reach high levels on 02 – 05 October, 07 – 09 October,
and 17 – 26 October.

The geomagnetic field is expected to range from quiet to major storm
levels during the period.  A returning coronal hole is expected on
05 – 08 October and could produce active to isolated minor storm
levels.  A large coronal hole is due to return on 14 – 22 October
and is expected to produce major storm levels.