:Product: Weekly Highlights and Forecasts
:Issued: 2001 Dec 19 2212 UT
Highlights of Solar and Geomagnetic Activity
10 - 16 December 2001

Activity ranged from low to high levels during the period. High
levels occurred on 11 and 13 December due to two major flares from
Region 9733 (N14, L = 313, class/area Eki/560 on 12 December).
Activity alternated between low and moderate levels during the rest
of the period. Region 9733’s first major flare was an impulsive
X2/2b at 11/0808 UTC, the second a X6/3b at 13/1430 UTC. The X6/3b
flare was associated with a partial-halo CME. Region 9733 was large
and magnetically complex through most of the period. It produced
impulsive low-level M- and C- class flares as it gradually decayed
following the X6 flare (for flare times, please refer to the
Energetic Events or Optical Flares lists). The other sunspot group
of interest was Region 9727 (S21, L = 020, class/area Eki/630 on 13
December), which produced isolated low-level M-class and C-class
flares during the period. Region 9727 was in a gradual growth phase
through 13 December, then stabilized as a large, magnetically
complex group with a possible delta magnetic configuration in its
northernmost trailer spots. It produced isolated subflares as it
crossed the west limb on 15 December.

Solar wind data were available from the NASA Advanced Composition
Explorer (ACE) spacecraft for most of the period. A relatively weak
high-speed stream associated with a positive-polarity coronal hole
was observed during the last two days of the period. Velocities and
temperatures were elevated during this time with intermittent
“gusts” in the 500 to 600 km/sec range. There were no significant
disturbances observed during the rest of the period.

There were no proton events detected at geo-synchronous orbit.

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

Geomagnetic field activity was at quiet to unsettled levels during
most of the period.

Forecast of Solar and Geomagnetic Activity
19 December 2001 - 14 January 2002

Solar activity is expected to range from low to moderate levels with
isolated low-level M-class flares likely. Isolated major flare
activity will also be possible during the period with the return of
previously active longitudes.

There will be a slight chance for a proton event during the period.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to be at normal levels during most of the period.

The geomagnetic field is expected to be at quiet to unsettled levels
during the period.

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