:Product: Weekly Highlights and Forecasts
:Issued: 2003 Dec 16 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
08 - 14 December 2003

Solar activity was at very low to low levels this period.  Activity
was at very low levels from 08 – 13 December and was marked by
numerous minor B-class flares.  Activity increased to low levels on
14 December with two C-class flares from Region 522 (N16, L=007
class/area Cso/30 on 14 December).  The largest of these two C
flares was a C2 at 2340 UTC on 14 December.  Region 522 appeared on
the northwest disk on 13 December with a beta magnetic
configuration.  The largest region on the disk during the period was
Region 520 (N02, L=009, class/area Dso/140 on 14 December.  This
region developed a beta magnetic configuration on 14 December but
has yet to produce activity above the B-class level.

Solar wind data were available from the NASA Advanced Composition
Explorer (ACE) spacecraft during most of the summary period.  Early
on 08 December, solar wind speeds increased to nearly 650 km/sec in
response to a large, recurrent, mid-disk coronal hole.  The Bz
component of the IMF, after an initial northward direction, turned
southward, and then began a north-south oscillation.  This signature
was consistent to that of a co-rotating interactive region that
normally precedes the onset of a high-speed stream.  Solar wind
speeds remained steady at 650 to 700 km/sec until midway on the 10th
when speeds further increased to 850 km/sec as the large coronal
hole moved into a more favorable position.  Solar wind speed dropped
back in the range of 700 – 800 km/s on 12 December and remained
there through the end of the period on 14 December.

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

The greater than 2 MeV electron flux at geosynchronous orbit reached
high levels on 09 – 16 December.

The geomagnetic field ranged from unsettled to major storm levels.
The onset of a coronal hole high speed stream on 08 December
produced active to minor storm levels every day during the period. 
Major storm levels were observed on 08 December in connection with
the co-rotating interaction region and again on 10 – 11 December
when solar wind speed increased above 800 km/s.

Forecast of Solar and Geomagnetic Activity
17 December 2003 - 12 January 2004

Solar activity is expected to range from very low to moderate levels.
Active longitudes are due to return to the visible disk early in
the period and may produce moderate level activity.  Expect mostly
low activity levels in early January.

There is a small chance for a greater than 10 MeV proton event from
mid to late December.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to reach high levels on 19 – 23 December, and again on 03 –
05 January.

Geomagnetic activity is expected to range from quiet major storm
levels.  Unsettled to minor storm periods are expected on 18 – 22
December, and again on 01 – 05 January due to high speed coronal
hole streams.  The large trans equatorial coronal hole is expected
to return 07 –12 January with major storm levels expected.