:Product: Weekly Highlights and Forecasts :Issued: 2002 Aug 20 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 12 - 18 August 2002 Solar activity ranged from low to high levels during the period. Activity increased to high levels on 16 August due to a long-duration M5/2n flare from Region 69 (S07, L = 298, class/area Ekc/1960 on 18 August) at 16/1232 UTC. This flare was associated with a 1600 sfu Tenflare, Type II and IV radio sweeps, and a full-halo CME. Region 69 was very large with multiple, persistent delta magnetic configurations. Moderate activity occurred during 13 – 15 and 17 – 18 August due to low-level M-class flares from Region 61 (N08, L = 041, class/area Ekc/360 on 09 August), Region 66 (N14, L = 332, class/area Dai/140 on 14 August), and Region 69. Solar wind data were available from the NASA Advanced Composition Explorer (ACE) spacecraft for most of the summary period. Recurrent positive-polarity coronal hole effects occurred through 14 August with peak velocities around 550 km/sec. A weak, CME-related shock passed the ACE spacecraft at about 15/1828 UTC. Wind speeds briefly reached 800 km/sec immediately following the passage, then decreased a bit with speeds as high as 670 km/sec through the first half of 16 August. Another CME-related shock passed ACE at approximately 18/1810 UTC associated with a sudden increase in velocities to as high as 600 km/sec. The Bz component of the IMF became more variable following the shock with a range of plus 10 to minus 13 nT (GSM). A greater than 10 MeV proton event began at geo-synchronous orbit at 14/0900 UTC, reached a peak of 26 pfu at 14/1620 UTC, and ended at 14/1950 UTC. Greater than 10 MeV proton fluxes remained enhanced for the rest of the period. The greater than 2 MeV electron flux at geo-synchronous orbit was at normal to moderate levels during 12 – 13 August. Fluxes were at normal to high levels for the rest of the period. Geomagnetic field activity ranged from quiet to active levels during 12 – 13 August with minor storm periods at high latitudes. Activity decreased to mostly quiet to unsettled levels on 14 August. Field activity increased to unsettled to minor storm levels during 15 – 16 August. Activity decreased to mostly quiet to unsettled levels during 17 August. Active to minor storm levels occurred late on 18 August following a sudden impulse at 18/1848 UTC (27 nT, as measured by the Boulder USGS magnetometer). Forecast of Solar and Geomagnetic Activity 21 August - 16 September 2002 Solar activity may reach high levels during 21 – 25 August. Otherwise, low to moderate levels are expected. There is a chance for a greater than 10 MeV proton event during the period. The greater than 2 MeV electron flux at geo-synchronous orbit is expected to be at normal to moderate levels during most of the period. However, high flux levels are possible beginning 10 September. Active geomagnetic field conditions are possible during 21 August and 5 – 12 September. Quiet to unsettled conditions are expected for the rest of the period. .