:Product: Weekly Highlights and Forecasts

:Issued: 2002 Oct 01 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

23 - 29 September 2002



Solar activity was at low to moderate levels.  Activity reached

moderate levels on 27 September and again on 29 September.  The

largest event was an M2.6/2n flare at 29/0639 UTC from Region 134

(N12, L=77, class/area Eai/250 on 29 September).  On 24 September,

Region 134 rotated onto the visible disk and has exhibited

consistent growth and increasing magnetic complexity, developing a

magnetic delta configuration in the large leader spot on 27

September.  On 27 September Region 134 produced an M1.8/Sf at

27/1312 UTC with an associated Type II radio sweep (400 km/s). 

Region 134 also produced numerous C-class flares later in the

summary period.  Region 125 (S09, L=166 class/area Dao/140 on 29

September) produced a long duration C7 flare at 29/0859 UTC that is

believed to be the source of a faint partial halo CME off the

western limb observed by SOHO/LASCO C2 imagery at 29/0830 UTC.



Solar wind data were available from the NASA Advanced Composition

Explorer (ACE) spacecraft for most of the summary period.  Solar

wind velocities were near 425 km/s at the being of the period and

steadily decline to a around 350 km/s on 25 September.  A weak

transient shock was observed late on 25 September and caused a

slight increase solar wind speed, temperature, and density.  On 27 –

29 September the solar wind velocity was steady near 325 km/s.  No

significant deflection in the Bz component of the IMF was noted.



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

normal to moderate levels.  Moderate levels were observed on 24 – 26

September.



The geomagnetic field was at quiet to unsettled levels.   Two

recurring coronal holes rotated onto the visible disk early in the

period.



Forecast of Solar and Geomagnetic Activity

02 - 28 October 2002



Solar activity is expected to be low to moderate for most of the

forecast period due to the growth and development of Region 134 and

the return of old Region 105/114 complex.



There is a chance of a greater than 10 MeV proton event during the

forecast period.



The greater than 2 MeV electron flux at geo-synchronous orbit may

reach event threshold on 11-13 October due to coronal hole effects.



The geomagnetic field is expected to be quiet to unsettled for most

of the forecast period.   On 09-10 October, a recurring coronal hole

in the southern hemisphere is expected to reach a geo-effective

position and may result in active conditions.





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