:Product: Weekly Highlights and Forecasts
:Issued: 2004 Aug 10 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
02 - 08 August 2004

Solar activity levels ranged from very low to low.  The summary
period began with low levels on 02 August as Region 655 (S09, L=176,
class/area, Eso/190 on 04 August) produced an isolated C3.9 X-ray
flare at 02/1754 UTC.  Activity levels decayed to very low on 03 –
07 August as only B-class flares were observed from Region 655 and
new Region 656 (S12, L=081, class/area, Eao/290 on 08 August).  By
08 August, activity levels rose to low as Region 656 produced two
minor C-class flares, the largest a C2.7/Sf at 08/1724 UTC.  A
backsided, full halo CME was observed by LASCO imagery beginning at
08/0854 UTC.

Solar wind data were available from the NASA Advanced Composition
Explorer (ACE) spacecraft during most of the summary period.  The
period began on 02 August with solar wind speed near 450 km/s and
trending downward.  By 07 August, wind speed had decayed to near 350
km/s.  During this period, the IMF Bz did not vary much beyond +/- 5
nT.  By 07/1000 UTC, wind speed began a gradual increase and ended
the day near 500 km/s.  The IMF Bz responded with a southward
turning to –14 nT for about two hours followed by a period of four
hours of Bz that oscillated between +/- 10 nT.  By the end of the
summary period, speed had decreased to near 425 km/s and the IMF Bz
did not vary much beyond +1 to –5 nT.

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 was at
high levels on 02 – 05 August.

The geomagnetic field ranged from quiet to minor storm levels.  The
period began with activity at quiet to unsettled levels.  The field
remained quiescent through 07/0900 UTC after which levels rose to
active to minor storm levels as a recurrent coronal hole high speed
stream began to influence the geomagnetic field.  Active conditions
persisted through 07/1800 UTC.  Thereafter, the activity declined to
quiet to unsettled conditions, and remained so through the end of
the summary period.

Forecast of Solar and Geomagnetic Activity
11 August - 06 September 2004

Solar activity is expected to range from very low to low.  Activity
levels are expected to increase to low to moderate after 12 August
when old Region 652 (L=348) is due to return.

A greater than 10 MeV proton event is possible after the return of
old Region 652.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to remain below event threshold for the forecast period.

The geomagnetic field is expected to range from quiet to unsettled
levels for most of the forecast period.  Late in the period, levels
are expected to increase to unsettled to active due to a weak,
recurrent coronal hole stream that is expected to be in a
geoeffective position.