:Product: Weekly Highlights and Forecasts :Issued: 2003 Jul 15 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 07 - 13 July 2003 Solar activity was at low to moderate levels. Activity on 07 – 08 July was at low levels with minor C-class flares predominantly from Regions 397 (N11, L=033 class/area Fkc/930 on 06 July) and 400 (N05, L=351, class/area Eki/290 on 06 July). On 07 July, Region 397 began to decay, lost its delta magnetic configuration by 08 July, and rotated beyond the east limb on 10 July. On 08 July, a large filament in the northwest quadrant erupted in parts: a 23-degree section near N30W22 erupted early in the period and a 21-degree section near N38W38 erupted at 08/1500Z. Region 397 produced moderate activity on 09 – 10 July with an M2 on 09 July at 2238 UTC and an M3 on 10 July at 1412 UTC. The M3 was the largest event of the period and was associated with a Type II radio sweep (1030 km/s). Activity was at low levels on 11 July. Before Region 409 (N16, L=194, class/area Eao/250 on 13 July) rotated around the east limb it produced an M1 flare on 12 July at 1906 UTC. This M1 flare was associated with a Type II radio sweep (659 km/s) and centimetric radio bursts. Activity was at low levels on 13 July. Solar wind data were available from the NASA Advanced Composition Explorer (ACE) spacecraft for most of the summary period. The period began with declining solar wind speed. Wind speed was near 600 km/s at the beginning of the period and decreased to 400 km/s by 10 July. Late on 10 July, a fifteen-hour period of negative Bz began along with a gradual rise in total field (Bt). This co-rotating interacting region marked the onset of a coronal hole high speed stream that began mid day on 11 July and lasted until late on 13 July. Maximum solar wind speed from the high speed stream reached 700 km/s with average speeds near 600 km/s. There were no greater than 10 MeV proton events at geosynchronous orbit during the period. The greater than 2 MeV electron flux at geo-synchronous orbit reached high levels on 07 – 10 July and again on 13 July. The geomagnetic field ranged from quiet to minor storm levels. A weak transient passed ACE early in the period and resulted in an isolated period of active conditions on 07 July. Other than this one isolated active period, activity on 07 – 10 July was at quiet to unsettled levels with mostly quiet levels on 08 – 10 July. On 11 - 12 July, activity was at active to major storm levels due to a coronal hole driven high speed stream. One period of severe storm levels was observed early on 12 July as high speed stream effects continued. The high speed stream subsided on 13 July with quiet to active levels. Forecast of Solar and Geomagnetic Activity 16 July - 11 August 2003 Solar activity is expected to range from very low to moderate levels with predominantly low level activity. Early in the period, activity is expected to be at low levels with the possibility for an isolated M-class event from Region 409. Regions 397 and 400 are due to return to the visible disk on 23 July and 27 July respectively. These regions may also have the potential for isolated M-class events. No greater than 10 MeV proton events at geosynchronous orbit are expected during the period. The greater than 2 MeV electron flux is expected to reach high levels on 16 – 18 July, 20 – 28 July, 30 July – 02 August and again 09 - 11 August on due to recurrent coronal hole high speed streams. The geomagnetic field is expected to range from quiet to major storm levels during the period. On 18 – 20 July, a coronal hole is expected to produce minor storm levels. A large southern coronal hole is due to return on 23 - 27 July and may produce periods of major storm levels. The trailing portion of this large coronal hole will be in a geoeffective position on 29 July – 01 August and is expected to produce minor storm levels. A third returning coronal hole is expected to be in a geoeffective position on 07 – 09 August and may produce major storm levels.