:Product: Weekly Highlights and Forecasts
:Issued: 2000 Oct 03 2112 UT
Highlights of Solar and Geomagnetic Activity
25 September - 01 October 2000

Solar activity varied from low to high levels. Activity was at
moderate levels on 25 September due to isolated, low-level M-class
flares from Regions 9169 (N11, L = 078, class/area Fkc/2140 on 19
September) and 9166 (S12, L = 123, class/area Eko/760 on 21
September). Activity dropped to low levels during 26 - 29 September
with isolated to occasional C-class subflares. Activity increased to
high levels on 30 September due to an X1/Sf flare at 30/2321 UTC
from Region 9169 as it was crossing the west limb. Region 9169 also
produced an M5 X-ray flare at 01/0701 UTC with an associated 200 SFU
Tenflare and a loop prominence system. This large, moderately
complex region had been gradually decaying for several days prior to
the major flare activity. Region 9178 (S23, L = 312, class/area
Dai/160 on 01 October) produced a long-duration M2/Sf at 01/1410 UTC
as well as a C3/Sf flare at 01/1304 UTC associated with a Type II
radio sweep. Both flares occurred during a period of growth in the
region.

Data were available from the Advanced Composition Explorer (ACE)
spacecraft for most of the period. A coronal hole signature was
observed during 25 - 28 September with velocities as high as 670
km/sec along with decreased densities. Coronal hole effects subsided
during 28 September. A transient signature was observed during 30
September - 01 October with a moderate increase in wind velocities
and densities, and periods of southward IMF Bz with deflections to
minus 16 nT (GSM). Earth was within a positive polarity (away) solar
sector during most of the period.

There were no proton events at geosynchronous orbit during the
period.

The greater than 2 MeV electron flux at geosynchronous orbit was at
moderate to high levels during 26 - 29 September. Fluxes were at
normal to moderate levels during the remainder of the period.

The geomagnetic field was disturbed during 25 - 28 September due to
coronal hole effects. Unsettled to active periods occurred during
this disturbance. Activity declined to quiet to unsettled levels on
29 September. Activity increased to unsettled to minor storm levels
on 30 September with major to severe storm periods detected at high
latitudes. Activity returned to quiet to unsettled levels during the
latter half of 01 October.

Forecast of Solar and Geomagnetic Activity
04 - 30 October 2000

Solar activity is expected to be at low to moderate levels. Isolated
M-class flares are expected sometime during the period. Chances for
major flare activity are expected to increase beginning 14 October
with the return of old Region 9169.

There will be an increased chance for a proton event at
geosynchronous orbit beginning 14 October with the expected return
of old Region 9169.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to be at moderate to high levels during 17 - 19 October.
Normal to moderate levels are expected during the remainder of the
period.

Geomagnetic field activity is expected to be at unsettled to minor
storm levels during 04 - 05 October due to recent CME activity.
Active to minor storm periods will be possible during 16 - 18
October due to coronal hole effects. Quiet to unsettled levels are
expected for the rest of the period, barring an Earth-directed CME.


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