:Product: Weekly Highlights and Forecasts
:Issued: 2005 Jan 04 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
27 December 2004 - 02 January 2005

Solar activity reached high levels during this reporting period.  At
the start of the period, very low conditions were observed as Region
713 (S10, L=125, class/area, Fai/190 on 22 December) was nearing the
west limb.  Only a few small B-class flares were observed from this
region and a region that was coming around on the northeast limb. 
On 28 December, conditions started to increase to low levels as
Regions 715 (N04, L=339, class/area, Dkc/350, on 30 December) had
rotated on the visible disk.  Regions 713 and 715 produced a
combined total of 11 C-flares.  On 29 through 31 December, solar
activity reached moderate levels.  Regions 713 and 715 produced
M-class flares on 29 December.  The largest of these was a M2, from
Region 715 (a beta-gamma-delta magnetic class), that occurred at
1627Z.  This flare had an associated Tenflare (510 sfu), a type II
radio sweep with an estimated shock speed of 411 km/s, and a CME
that was not earth directed.  On 30 December,  Region 715 produced
several M-flares; the largest of these was a M4/2n flare at 2218Z
along with an associated Tenflare (230 sfu), type IV radio sweep,
type II radio sweep with an estimated shock speed of 1378 km/s, and
a related CME that had a slight earth directed component.  On 31
December, Region 715 produced an M1 flare at 1445Z.  On 01 January,
solar activity reached high levels as Region 715 produced an X1.7 at
0031Z with an associated type IV radio sweep, type II radio sweep
with an estimated shock speed of 760 km/s, and a CME that was
expected to be geoeffective.  Region 715 started a decay phase on 01
January and continued the trend on 02 January as it decreased in
both area and magnetic complexity.  On 02 January, low conditions
were observed as Region 715 (a beta-gamma magnetic class) was
responsible for isolated low C-class and B-class flares.

Solar wind data were available from the NASA Advanced Composition
Explorer (ACE) spacecraft during most of the summary period.  The
period began with solar wind speed near 450 km/s.  At approximately
0600Z on 27 December, Solar wind speed increased to approximately
590 km/s and declined until 1400Z on 28 December.  The spike in
solar wind was the result of a geoeffective coronal hole high speed
stream.  Solar wind speed declined to around 450 km/s until 19
December when the effects of a transequatorial coronal hole high
speed stream were felt as the solar wind increased to a maximum of
520 km/s just after 0800Z on 30 December.  Solar wind speed was in a
decline phase thereafter until 01 January when it leveled of at
about 420 km/s.  Solar wind speed showed another increase on 02
January as it increased to between 700 and 850 km/s and remained
there the rest of the day.  The reason for this increase was another
geoeffective coronal hole high speed stream, possibly combined with
a weak transient flow from the late December CME activity.

No greater than 10 MeV proton events were observed this period.

The greater than 2 MeV electron flux at geosynchronous orbit
increased to high levels on 29 and 30 December, and on 01 January.

The geomagnetic field ranged from quiet to minor storm levels with
isolated severe storm periods at high latitudes. The period began
with quiet to unsettled levels on 27 December.  Quiet to active
levels were experienced on 28 December due to sustained periods of
southward Bz around 5nT.  On 29 December, quiet to active levels
were seen with an isolated minor storm period at mid-latitudes. 
Increased activity continued into 30 December due to the effects of
a transequatorial high speed coronal hole stream.  On 31 December,
conditions were quiet to unsettled.  On 01 January, quiet to active
conditions were experienced as geomagnetic activity started to
increase due to the onset of a geoeffective coronal hole high speed
stream.  On 02 January, Quiet to minor storm levels were observed,
with severe storm periods at high latitudes, due to the high speed
stream, possibly combined with a weak transient flow.

Forecast of Solar and Geomagnetic Activity
05 - 31 January 2005

Solar activity is expected to be very low to low with a chance of
M-class activity from Region 715.  Region 715 will be departing on
10 January.  Expect very low to low conditions after 10 January. 
Expect very low to low with a chance of M-class activity from old
Region 715 again as it rotates back on the visible disk on 23
January.

A greater than 10 MeV proton event is not expected.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to be at high levels on 14-15, 18-19, 25-27, and 30-31
January.

The geomagnetic field is expected to range from mostly quiet to
active levels with isolated minor storm periods. High speed coronal
hole streams are expected to produce occasional storm periods on
13-14, 17-18, 24-26, and 29-30 January.  Otherwise, expect quiet to
unsettled conditions.