:Product: Weekly Highlights and Forecasts
:Issued: 2003 May 06 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
28 April - 04 May 2003

Solar activity ranged from low to moderate levels.  Region 349 (S14,
L= 154, class/area Ekc/1120 on 01 May) was the largest spot group of
the period and exhibited significant growth through most of the
period.  However, activity from this region was low, producing only
C-class flares.  

The period began on 28 April with low level
activity due to a C4/Sf flare from Region 337 (S14, L=240,
class/area Dac/270 on 28 April).   Moderate levels were observed on
29 April with an M1/1f flare from Region 337 at 0459 UTC.  Region
337 rotated beyond the west limb on 01 May.  Activity was at low
levels on 30 April – 01 May.  Nearly all of the C-class activity on
these two days was from Region 349 with the largest flare a C5/Sf on
01 May.  Region 345 (S17, L=167, class/area Dao/130 on 02 May)
produced a long duration M1/Sf flare on 02 May.  This region was of
moderate complexity and developed an east-west inversion line on 01
– 02 May.  On 03 – 04 May, activity returned to low levels with
minor C-class flares.

Solar wind data were available from the NASA Advanced Composition
Explorer (ACE) spacecraft for most of the summary period.  Solar
wind increased to near 550 km/s on 29 April due to the combination
of a coronal hole high speed flow and transient flow from earlier
activity.  On 30 April, solar wind speed further increased to 650
km/s.  Velocity gradually declined over the remainder of the period
and ended the period around 400 km/s. The Bz component of the
interplanetary magnetic field exhibited transient flow signatures
during most of the period.

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 everyday of the period, 28 April – 04 May.

The geomagnetic field was at quiet to major storm levels.  The period
began on 28 April with quiet to minor storming due to a weak
transient passage detected by the ACE spacecraft.  Activity on 29
April – 02 May, reached minor storming with isolated major storming
on 30 April and 01 May.  This activity was due to the elevated solar
wind speed from a negative polarity coronal hole high speed stream
and transient flow.  On 03 – 04 May activity was at quiet to
unsettled conditions as solar wind speed declined.

Forecast of Solar and Geomagnetic Activity
07 May - 02 June 2003

Solar activity is expected to range from low to moderate activity. 
Activity is expected to be at low levels early in the period until
Region 338 returns to the visible disk on 11 May.  Region 345/349
are due to return on 19 May.  These regions are expected to present
isolated M-class potential for the remainder of the period.

No greater than 10 MeV proton events are expected during the forecast
period.

The greater than 2 MeV electron flux is expected to reach high levels
early in the period, 07 – 09 May.  High levels are also expected on
12 – 23 May and again on 27 May – 02 June.

The geomagnetic field is expected to range from quiet to isolated
major storm levels.  Early in the period a large negative polarity
coronal hole high speed flow is expected to produce unsettled to
minor storm conditions.  On 13 – 14 May, isolated major storm levels
are possible with the return of a large coronal hole high speed
flow.  Late in the period a positive polarity is due to return and
may produce unsettled to major storming on 27 – 30 May.