:Product: Weekly Highlights and Forecasts
:Issued: 2003 May 27 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
19 - 25 May 2003

Solar activity was at very low to low levels.  The period began on 19
May with very low levels.  Activity increased to low levels on 20 –
22 May.  Region 364 (S24, L=295, class/area Dso/100 on 20 May)
produced three C-class flares on 20 May.   Region 362 (S12, L=245,
class/area Dao/110 on 21 May) produced four C-class flares on 22
May.  The largest event of the period was a C4 flare from Region 362
on 22 May at 0542 UTC.  Activity on 23 – 24 May decreased to very
low levels.  The period ended on 25 May with low levels due to a C3
flare from Region 368 (S32, L=160, class/area Hax/180 on 22 May). 
As the period ended, Region 365 (S08, L=181, class/area Dai/190 on
25 May) entered a rapid growth phase.

Solar wind data were available from the NASA Advanced Composition
Explorer (ACE) spacecraft for most of the summary period.  On 21
May, solar wind speed increased from 400 km/s to over 600 km/s due
to a geo-effective coronal hole.  Wind speed was steady on 22 May
near 500 km/s and was in gradual decline on 23 May.  On 24 May,
solar wind speed increased to around 550 km/s and remained elevated
at that level through the end of the period.  The Bz component of
the interplanetary magnetic field exhibited high speed flow
signature for most of the period oscillating between +/- 8 nT.  On
21 May, there was a brief period of southward Bz near -13 nT.

There were no greater than 10 MeV proton events at geo-synchronous
orbit during the summary period.

The greater than 2 MeV electron flux at geo-synchronous orbit reached
high levels on 23 – 25 May.

The geomagnetic field ranged from quiet to minor storm levels.  The
period began with quiet to unsettled levels on 19 – 20 May.  On 21
May, a coronal hole rotated into a geo-effective position and
produced quiet to minor storm levels through 23 May.  High speed
stream effects continued through the end of the period and produced
unsettled to minor storm levels on 24 – 25 May.

Forecast of Solar and Geomagnetic Activity
28 May - 23 June 2003

Solar activity is expected to be at low to moderate levels.  Moderate
levels are expected early in the period as Region 365 continues to
grow.  Activity from beyond the northeast limb indicates new active
regions will rotate onto the visible disk early in the forecast
period.  These new regions are expected to keep activity at moderate
levels through the first half of the period.

Greater than 10 MeV proton events are not expected during the
forecast period.

The greater than 2 MeV electron flux is likely to reach high levels
on 30 May – 01 June, and again on 08 – 16 June due to recurring high
speed solar wind streams.

The geomagnetic field is expected to range from quiet to active
levels with some isolated major storm periods.  A small coronal hole
high speed flow is expected on the first couple of days of the
period and may produce some minor storm periods.  On 04 – 12 June, a
large southern coronal hole will rotate into a geo-effective
position and is expected to produce active to minor storm levels. 
The period should end with a third coronal hole high speed flow
producing unsettled to active conditions on 17 – 22 June.