:Product: Weekly Highlights and Forecasts
:Issued: 2001 May 15 2112 UT
Highlights of Solar and Geomagnetic Activity
07 - 13 May 2001

Solar activity ranged from low to moderate levels. Activity was low
through 11 May, mostly due to C-class flares from Regions 9445 (N24,
L = 027, class/area Fai/390 on 01 May) and 9455 (S18, L = 273,
class/area Dao/190 on 12 May). Region 9445 gradually decayed before
crossing the west limb on 10 May. Multiple CMEs were observed early
on 07 May from beyond the west limb, one of which was associated
with a solar proton event (see the description below). Activity
increased to moderate levels during 12 - 13 May due to two low-level
M-class flares from Region 9455 (see the Energetic Events listing
for flare specifics). Coronal mass ejections were observed in the
wake of both flares, but neither appeared Earth-directed. Region
9455 was a moderate-sized group with a minor degree of magnetic
complexity that showed little change during the period. The same was
true of Region 9454 (N13, L = 231, class/area Eko/430 on 11 May),
which produced isolated C-class flares early in the period. Old
Region 9415 (S22, L = 001, class/area Eko/880 on 07 April), which
was responsible for major flare activity during its previous
rotation, returned as a spotless plage area. Enhanced emission near
the northeast limb at the time of this report suggest the possible
active return of old Region 9433 (N17, L = 155, class/area Fki/790
on 21 April).

Data were available from the Advanced Composition Explorer (ACE)
spacecraft for most of the period. Multiple CME passages occurred
during the period. The first CME passage began around 08/1500 UTC
and continued through 10 May. Winds gradually increased to a peak of
610 km/sec by 09/0000 UTC, then gradually decreased to near nominal
speeds by the end of 09 May. A prolonged period of southward IMF Bz
was also associated with this passage. It occurred during 09/0800 -
10/0800 UTC with maximum southerly deflections to minus 09 nT (GSM).
Two CME passages occurred during 11 - 12 May. The first CME boundary
reached Earth around 11/2100 UTC followed by a second at around
12/1000 UTC.  Velocities increased following the passages with peaks
to near 700 km/sec detected on 12 May. Intermittent periods of
southward IMF Bz were associated with these passages as well, with
maximum deflections to minus 15 nT. A high-speed coronal hole wind
stream commenced around 13/1500 UTC associated with increased
velocities (peaks to around 600 km/sec) and decreased densities.

A proton event at greater than 10 MeV occurred during 07 - 08 May,
likely associated with an event beyond the west limb early on 07
May. The proton event began at 07/1915 UTC, reached a peak of 29 PFU
at 08/0825 UTC, then ended around 08/1730 UTC.

The greater than 2 MeV electron flux at geosynchronous orbit was at
normal to high levels. High flux levels occurred on 09, 11, and 13
May.

The geomagnetic field was disturbed during the period due to multiple
CME passages and a high speed stream associated with a coronal hole.
Unsettled to minor storm periods occurred during most days with
isolated major storm periods at high latitudes.

Forecast of Solar and Geomagnetic Activity
16 May - 11 June 2001

Solar activity is expected to range from low to moderate levels
during the period. Isolated M-class flares will be possible during
the period.

No proton events are expected during 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. High flux levels will be possible during the last few days
of the period.

The geomagnetic field is expected to be at quiet to unsettled levels
during most of the period (barring an Earth-directed CME). However,
active conditions will be possible around 09 June due to coronal
hole effects.

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