:Product: Weekly Highlights and Forecasts :Issued: 2002 Sep 17 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 09 - 15 September 2002 Solar activity was at low to moderate levels. Moderate levels were observed on 09-11 September and 15 September. The largest event was an M2.9/1n on 10 September from Region 105 (S08, L=297, class/area Fki/1520 on 10 September). This event was associated with a Type II and Type IV radio sweep. For flare times and magnitudes, please refer to the Energetic Events or Optical Flare lists. Region 105 produced all the M-class activity during the period. This large magnetically complex spot group appeared to be two separate regions when viewed in white light, however, magnetogram data indicated a single bi-polar region with a common negative polarity field between the main leader spot and large trailing spot. This condition changed on 14 September when a positive polarity field developed between the two main spots. On 14 September the region was split and the trailing spot was designated Region 114 (S12, L=288 class/area Dkc/470 on 14 September). Solar wind data were available from the NASA Advanced Composition Explorer (ACE) spacecraft for most of the summary period. A persistent negative Bz was observed on 10 September with solar wind velocities near 450 km/s. At 11/0800 UTC, solar wind velocities began to increase and reached peak velocities around 550 km/s. This increase was due to a large, equatorial extension of the south polar coronal hole. Coronal hole effects continued until 13 September when solar wind velocity began a steady decline and stabilized on 15 September near 350 km/s. 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 was at normal to high during the period. Electron flux reached high levels on 13-15 September due to the coronal hole effects mentioned above. The geomagnetic field was at quiet to major storm levels. Minor storm levels were observed on 10 September mainly due to the persistent period of negative Bz mentioned above. Major storm levels occurred on 11 September due to the onset of coronal hole effects. Active conditions were observed on 12-14 September due to the continued coronal hole effects. Forecast of Solar and Geomagnetic Activity 18 September - 14 October 2002 Solar activity is expected to be low to moderate. Activity is expected to be at moderate levels through 21 September, due to the Region 105/114 complex. Continued moderate conditions may accompany the return of old Region 95 (N08, L=061) after 23 September. A slight chance for a proton event exists in association with any significant flare activity from the Region 105/114 complex, until it rotates beyond the west limb on 21 September. The greater than 2 MeV electron flux at geo-synchronous orbit may remain at event thresholds on 18 September, due to the coronal hole effects of the past few days. Recurring electron events are possible on 02-03 October and 09-10 October, due to expected rotation of persistent coronal holes. The geomagnetic field may reach active levels on 19-20 September, in response to potential transient effects from recent CME activity observed on 17-18 September. Quiet to unsettled conditions are expected for most of the remaining forecast period, with the possibility of isolated active conditions on 01-02 October and 08-09 October in response to recurrent coronal hole effects. .