:Product: Weekly Highlights and Forecasts
:Issued: 2000 Oct 17 2112 UT
Highlights of Solar and Geomagnetic Activity
09 - 15 October 2000

Solar activity varied from low to moderate levels. Activity was low
during 09 - 10 October with isolated C-class flares. Most of these
flares were produced by Region 9182 (N03, L = 246, class/area
Dai/360 on 11 October) as it gradually developed, including a
long-duration C6/1F flare at 09/2343 UTC with associated Type II and
IV radio sweeps and a halo CME. Activity increased to moderate
levels on 12 October due to a long-duration M1/Sf flare at 12/2049
UTC from Region 9182, which continued to gradually develop. Activity
dropped to low levels on 13 October with isolated C-class subflares.
Activity returned to moderate levels on 14 October as Region 9182
produced an M1/Sf flare at 14/0840 UTC as it was crossing the west
limb. Activity decreased to low levels on the last day of the period
with isolated C-class subflares. There were two long-duration,
optically uncorrelated C-class X-ray flares detected on 15 October
as well: a C3 at 15/0836 UTC and a C2 at 15/2212 UTC. Both flares
may have been produced beyond the west limb from old Region 9182.

Data were available from the Advanced Composition Explorer (ACE)
spacecraft for most of the period. A CME, associated with the
long-duration C6/1F at 09/2343 UTC, passed the spacecraft at 12/2145
UTC. The CME passage was accompanied by a velocity jump from 326 to
438 km/sec, a total field increase from 08 to 18 nT, a minor density
increase, and variable IMF Bz with southerly deflections to minus 20
nT (GSM). There was a period of sustained southward Bz during
13/1600 - 14/1600 UTC with maximum southerly deflections to minus 12
nT. A coronal hole signature was observed during 14 - 15 October
with increased velocities (peaks to 610 Km/sec on 15 October), low
densities, and variable Bz.

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

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

The geomagnetic field was at mostly quiet to unsettled levels during
09 - 12 October with brief active levels. The field was disturbed
during 13 - 14 October due to a CME passage. Active to major storm
periods occurred during both days. Field activity decreased to quiet
to unsettled levels on 15 October.

Forecast of Solar and Geomagnetic Activity
18 October - 13 November 2000

Solar activity is expected to be at low to moderate levels. Isolated
M-class flares are expected sometime during the period.

There will be a slight chance for a proton event at geosynchronous
orbit during the latter half of the forecast period.

The greater than 2 MeV electron flux at geosynchronous orbit may
reach moderate to high levels during 22 - 23 October. Otherwise,
normal to moderate fluxes are expected.

Geomagnetic field activity may increase to active levels on 18
October due to weak CME effects. Active to minor storm levels will
be possible during 21 - 22 October due to coronal hole effects.
Quiet to unsettled levels are expected during the rest of the
period, barring an Earth-directed CME.