:Product: Weekly Highlights and Forecasts
:Issued: 2001 Aug 28 2112 UT
Highlights of Solar and Geomagnetic Activity
20 - 26 August 2001

Solar activity ranged from low to high levels throughout the period.
Activity was low on 20, 21, and 23 August with isolated B- and
C-class flares. Activity was moderate on 22, 24, and 26 August, with
a single M1 event occurring on each day. Activity reached high
levels on 25 August when Region 9591 (S19, L = 298, class/area
Fki/650 on 25 August) produced several M-class flares and an X5/3b
event at 25/1645 UTC. This event had an associated 8100 sfu
tenflare, Type II and Type IV radio sweeps, and a full halo coronal
mass ejection. Region 9591 was by far the most active region during
the period. It maintained a relatively large area (600 - 750
millionths) and a beta-gamma-delta magnetic configuration throughout
the period. Region 9591 appears to be old returning Region 9557
(S20. L=288, class/area Dki/600 on 07 August) that may have merged
with another region. Two other events of note occurred during the
period. The first was an eruptive prominence on the limb (EPL) near
southeast 20 on about 20/1920 UTC. This event was accompanied by a
long-duration C2 x-ray burst, a Type II radio sweep, and various
radio bursts. The second event was a filament eruption in the
southeast quadrant in concurrence with a long-duration C2 X-ray
event that peaked at 21/1303 UTC and a non-earth directed coronal
mass ejection.

Solar Wind data were available from the Advanced Composition Explorer
(ACE) spacecraft for most of the period. A high speed stream was
noted on 22 August with solar wind speed reaching the 550 to 650
km/s range. Solar wind speed for the rest of the period was mostly
in the 350 to 450 km/s range.

The greater than 10 MeV proton flux was slightly enhanced on 20
August following the proton event that occurred on 16-18 August.
There were no other proton events during the period.

The greater than 2 MeV electron flux at geosynchronous orbit was at
normal to moderate levels during the period.

The geomagnetic field was mostly quiet to unsettled during the
period. Active conditions were noted on 22 August due to a
recurrent, negative-polarity coronal hole and its corresponding high
speed stream impacting earth. Active conditions were also noted on
25 August due to possible coronal hole effects.

Forecast of Solar and Geomagnetic Activity
29 August - 24 September 2001

Solar activity is expected to be at low to moderate levels. Isolated
M-class flares are possible. There will be a chance for a major
flare during the first half of the period until Region 9591 leaves
the visible disk on 04-05 September.

There will be a chance for a solar proton event during the first half
of the period.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to be at normal to moderate levels during most of the
period. However, there will be slight chance for high flux levels
around 03 - 04 September.

Active geomagnetic field conditions will be possible around 27-29
August, 01 - 02 and 09 - 10 September. Otherwise, quiet to unsettled
levels are expected.


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