:Product: Weekly Highlights and Forecasts :Issued: 2003 Jul 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 June 2003 Solar activity was at very low to low levels. Activity on day one of the period was at very low levels and for the remainder of the period activity was at low levels. Region 386 (S07, L=187, class/area Ekc/290 on 18 June) began the period in gradual decay, simplifying to a beta-gamma configuration on 23 June and by 27 June was no longer visible. Region 391 (N14, L=164, class/area Dao/190 on 26 June) developed rapidly on 23 June to an area of 290 millionths with a beta magnetic configuration. This region was the source of low level activity on 24 June, producing four C-class flares. The growth rate of Region 391 slowed on 25 – 26 June and the region entered decay phase on 27 June. Activity on 25 – 27 June came from Region 397 (N12, L=034, class/area Fho/790 on 29 June) beyond the northeast limb. Activity included a long duration C3 on 25 June at 1632 UTC and a C3 on 27 June at 0321 UTC. The largest flare of the period was an impulsive C4 at 0656 UTC on 28 June from Region 391. The period ended with a C3 flare at 1101 UTC on the west limb, most likely Region 387 (N18, L=169, class/area Eao/270 on 22 June). Real time Solar wind data were available from the NASA Advanced Composition Explorer (ACE) spacecraft for most of the summary period. Solar wind speeds were elevated near 500 – 600 km/s early in the period due to coronal hole high speed streams. Late on 26 June a large southern coronal hole increased solar wind speed to near 650 km/s. Wind speed continued to increase on 27 – 29 June reaching peak values near 800 km/s and average values near 700 km/s. The Bz component of the interplanetary magnetic field associated with this high speed stream exhibited an oscillating signature with average values near –4nT and peak values near –10nT. 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 23 and 25 –29 June. The geomagnetic field ranged from quiet to major storm levels. The elevated solar wind produced isolated periods of minor storm levels on 23 June. Sustained minor storm levels were observed on 24 June. Activity on 25 – 26 June was at unsettled to active levels with solar wind speed steady near 550 km/s. Late on 26 June a large coronal hole rotated into a geoeffective position and produced active to major storm levels on 27 – 28 June and minor storm levels on 29 June. Forecast of Solar and Geomagnetic Activity 02 - 28 July 2003 Solar activity is expected to range from very low to moderate levels during the period. Region 397 may develop M-class potential early in the period. Activity for the remainder of the period is expected to be very low to low. 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 02 – 03 July, 06 – 08 July, 12 – 14 July, 16 – 18 July, and again on 20 – 28 July due to recurrent coronal hole high speed streams. The geomagnetic field is expected to range from quiet to major storm levels during the period. Minor storm levels are possible on 03 - 07 July, and again on 18 – 20 July due to smaller recurrent coronal hole high speed streams. Unsettled to major storm levels are possible on 14– 16 July due to small but intense coronal hole high speed stream. A larger southern coronal hole is due to return on 23 July, and could produce major storm levels possible.