:Product: Weekly Highlights and Forecasts
:Issued: 2001 Jul 25 2112 UT
Highlights of Solar and Geomagnetic Activity
16 - 22 July 2001

Solar activity ranged from very low to moderate levels. Activity was
moderate at the start of the period due to an isolated M1/1n flare
at 16/0320 UTC from Region 9539 (S18, L = 165, Eai/220 on 17 July),
which was in a gradual growth phase at the time of the flare. Region
9539 began to gradually decay on 17 July and was relatively quiet
for the rest of the period. Activity dropped to low levels during 17
- 18 July with isolated B- and C-class X-ray flares. Activity
returned to moderate levels on 19 July by virtue of an isolated
M1/1b flare from Region 9537 (S08, L = 166, class/area Dso/070 on 16
July), which was in a gradual decay phase prior to the flare.
Activity dropped to low to very low levels during the rest of the
period with isolated B- and C-class subflares, mostly from Region
9543 (S23, L = 077, class/area Eai/380 on 22 July). This region
began a gradual development phase on 19 July that continued as the
period ended.

Data were available from the Advanced Composition Explorer (ACE)
spacecraft for most of the period. A high speed stream was observed
during 16 - 20 July associated with a positive-polarity coronal
hole. Velocities gradually increased during 16 - 18 July with peaks
as high as 760 km/sec detected on 18 July. Coronal hole effects
gradually subsided during 18 - 20 July. There were no significant
disturbances observed during the rest of the period.

There were no proton events during the period.

The greater than 2 MeV electron flux at geosynchronous orbit reached
high levels during 19 - 21 July.

Geomagnetic field activity was at quiet to active levels during 16 -
17 July due to coronal hole effects. Activity decreased to quiet to
unsettled levels for the rest of the period.

Forecast of Solar and Geomagnetic Activity
25 July - 20 August 2001

Solar activity is expected to range from low to moderate levels.
Isolated M-class flares will be possible during the period. There
will be a slight chance for a major flare during the period.

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 to moderate levels during most of the
period. However, high flux levels will be possible around 15 - 16
August.

The geomagnetic field is expected to be at quiet to unsettled levels
during most of the period, barring an Earth-directed CME. However,
brief active periods will be possible during 25 - 26 July and 12 -
13 August due to coronal hole effects.


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