:Product: Weekly Highlights and Forecasts :Issued: 2002 Aug 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 29 July - 04 August 2002 Solar activity ranged from low to high levels for the fifth consecutive week. Activity alternated between low and moderate levels during 29 July – 02 August due to C-class flares and isolated M-class flares from Region 39 (S15, L = 204, class/area Fkc/940 on 26 July) and Region 44 (S21, L = 210, Fkc/780 on 01 August). For flare times and magnitudes, please refer to the Energetic Events or Optical Flares lists. Events of note during this period included a filament eruption from the northwest quadrant early on 29 July associated with a partial-halo CME and a long-duration M4 at 29/1044 UTC from Region 44. Activity increased to high levels during 03 – 04 August with an impulsive X1/Sf flare at 03/1907 UTC from Region 39 and an M6 X-ray flare at 04/0955 UTC from beyond the southwest limb near (old) Regions 39 and 44 (both regions departed the visible disk early on 04 August). Solar wind data were available from the NASA Advanced Composition Explorer (ACE) spacecraft for most of the summary period. Three CME-related shock passages occurred during the period. They passed the ACE spacecraft at approximately 29/1330 UTC, 31/1100 UTC, and 01/0425 UTC. All were likely due to CME activity from Regions 39 and/or 44. Peak solar wind velocities associated with these passages were in the 500 to 550 km/sec range. IMF Bz was mostly northward following the passages. However there were brief periods of southward Bz with maximum deflections to minus 12 nT (GSM). There were no proton events at geo-synchronous orbit. Greater than 2 MeV electron fluxes at geo-synchronous orbit were at normal to moderate levels. Geomagnetic field activity was at quiet to unsettled levels during the first half of 29 July, then increased to unsettled to active levels following a weak sudden impulse (SI) at 29/1330 UTC (9 nT, Boulder USGS magnetometer). Field activity decreased to quiet to unsettled levels during 30 – 31 July. Activity increased to unsettled to minor storm levels on 01 August following a SI at 01/0511 UTC (26 nT, Boulder USGS magnetometer). Another SI was observed at 01/2313 UTC (66 nT, Boulder USGS magnetometer). Field activity ranged from quiet to major storm levels on 02 August. Field activity ranged from quiet to minor storm levels during 03 – 04 August. Forecast of Solar and Geomagnetic Activity 07 August - 02 September 2002 Solar activity is expected to range from low to moderate levels. Isolated low-level M-class flares are expected during the period. However, there is a chance for isolated major flare activity during the second half of the period with the return of old Regions 39 and 44. There will be a chance for a proton event during the latter half of the period. Greater than 2 MeV flux levels are expected to be at normal to moderate levels during most of the period. Geomagnetic field activity is expected to be at quiet to unsettled levels during most of the period. However, active conditions are possible during 7 - 8 and 23 August due to coronal hole effects. .