:Product: Weekly Highlights and Forecasts
:Issued: 2003 Aug 26 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
18 - 24 August 2003

Solar activity was at very low to low levels.  The period began on 18
August with low level activity.  Moderate activity was observed on
19 August with two M-class flares from Region 431 (S13, L=194,
class/area/mag Ekc/500/Bgd on 14 August).  The first M-flare was an
impulsive M2/1n at 0759 UTC.   The second M-flare was an M2.7/2f at
1006 UTC with associated Type II (614 km/s), Type IV radio sweeps
and a CME that was not Earth directed.  Activity on 20 – 24 August
ranged from very low to low levels.  A C4 flare occurred on 21
August from Region 431 beyond the west limb and a C1 flare occurred
on 24 August from Region 436 (N07, L=88, class/area/mag Esi/170/B on
21 August).  Region 431 continued its decay early in the period and
rotated beyond the west limb on 21 August.  Region 436 showed some
growth and increasing magnetic complexity on 22 August but
stabilized by 23 August.  The only activity from this region has
been minor C-class flares.

Solar wind data were available from the NASA Advanced Composition
Explorer (ACE) spacecraft for most of the summary period.  Late in
the last summary period (17 August), a shock passed the NASA/ACE
spacecraft at 1340 UTC with solar wind speeds near 550 km/s and Bz
initially oriented northward.  At 0100 UTC on 18 August, Bz turned
southward to sustained values averageing about -15 nT with a peak
near -25 nT.  By 19 August the transient flow had passed, Bz
returned to a northward orientation, and solar wind speeds decreased
to 450 km/s. On 20 – 21 August, ACE solar wind data indicated the
gradual onset of a coronal hole high-speed-stream with solar wind
speed gradually increasing to 700 km/s and Bz fluctuating between
+/- 10 nT.

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 on 20 – 24 August.

Geomagnetic activity ranged from quiet to severe storm levels.  On 18
August, as the shock passed ACE, the southward shift in Bz resulted
in sustained minor to severe storm levels which continued until
early on 19 August.  The storm ended early on 19 August and
geomagnetic activity diminished to quiet to active levels for the
remainder of 19 August and through 20 August.  Activity on 21 – 24
August ranged from unsettled to severe storm levels due to the onset
of the coronal hole high speed stream.  Isolated periods of major
storm levels were observed on 21 – 22 August and isolated periods of
severe storm levels were observed on 21 August and again on 23
August.

Forecast of Solar and Geomagnetic Activity
27 August - 22 September 2003

Solar activity is expected to range from very low to low levels
during the period.  There is a slight chance of isolated moderate
activity from returning Region 424 after 28 August.

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

The greater than 2 MeV electron flux is expected to reach high levels
on 05 – 07 September, 10 – 12 September and again on 20 – 22
September.

The geomagnetic field is expected to range from quiet to major storm
levels.  A returning coronal hole high speed stream is expected to
produce active to major storm conditions on 02 – 05 September. 
Minor storm levels are possible from a smaller high speed stream on
08 – 09 September.  Toward the end of the period a third coronal
hole high speed stream is expected to return with active to major
storm levels possible on 17 – 21 September.