:Product: Weekly Highlights and Forecasts
:Issued: 2002 Apr 16 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
08 - 14 April 2002

Solar activity ranged from low to high levels. Activity was low on 08
April with frequent C-class flares, most of which were produced by
Region 9899 (N18, L = 179, class/area Dao/220 on 10 April). Activity
increased to moderate levels on 09 April due to two M-class flares
from Region 9899 including an M2/2b flare at 09/0042 UTC associated
with Type II and IV radio sweeps (for other flare magnitudes and
times, please refer to the Energetic Events or Optical Flares
lists). It also produced an M1 X-ray flare at 10/1907 UTC and a
C3/Sf flare at 12/0512 UTC, both associated with Type II and IV
radio sweeps. Region 9899 grew at a gradual pace during most of the
period, with minor mixed polarities near its large leader spot.
Activity increased to high levels on 10 April due to an impulsive
M8/1n flare at 10/1231 UTC from Region 9893 (N19, L = 215,
class/area Eai/490 on 09 April) associated with a Type II radio
sweep and a 510 sfu Tenflare. Region 9893 was part of a two region
complex that included Region 9901 (N20, L = 204, class/area Dai/250
on 13 April), which rapidly emerged just to the east of Region 9893.
The M8/1n flare occurred near the junction of these two groups where
a magnetic delta configuration had formed. This delta configuration
dissipated, but another delta developed in the leader spots of
Region 9901 and persisted through the rest of the period. Activity
alternated between low and moderate levels during 11 – 14 April with
isolated M-class flares from the Region 9893/9901 complex including
an M4/1f at 12/1802 UTC associated with a Type IV radio sweep.

Solar wind data were available from NASA Advanced Composition
Explorer (ACE) spacecraft for most of the summary period. No
significant disturbances were detected. However, minor changes were
observed during 11 – 14 April including intermittent periods of
sustained southward IMF Bz (maximum southward deflections to minus 9
nT (GSM)) and brief periods of elevated solar wind velocities (peaks
to 530 km/sec on 11 April).

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

Greater than 2 MeV electron fluxes at geo-synchronous orbit were at
normal to moderate levels during 08 – 10 April, then decreased to
normal levels for the rest of the period.

Geomagnetic field activity was at quiet to unsettled levels during 08
– 10 April. Activity increased to quiet to active levels during 11 –
14 April, though the active periods were brief.

Forecast of Solar and Geomagnetic Activity
17 April - 13 May 2002

Solar activity is expected to be at low to moderate levels during the
period. Isolated lesser M-class flares are likely during 17 - 21
April and 29 April – 13 May. There will be a slight chance for
isolated major flare activity during these periods as well. Activity
is expected to be low during 22 – 28 April.

There will be a slight chance for a proton event through 20 April and
again during 07 – 13 May.

Greater than 2 MeV fluxes may reach high levels around 30 April – 02
May. Normal to moderate flux levels are expected during the rest of
the period.

Active geomagnetic field conditions are likely during 17 – 18 April
due to an expected CME passage. Active conditions will also be
possible during 27 – 30 April due to recurrent coronal hole effects.


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