:Product: Weekly Highlights and Forecasts :Issued: 2003 Jan 28 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 20 - 26 January 2003 Solar activity was at low to moderate levels. The period began at low levels, highlighted by several minor C-class flares from Region 260 (N14, L=025, class/area Dao/70 on 21 January). Moderate activity was observed on 21 – 24 January with three low M-class flares observed in Region 266 (S22, L=345, class/area Fai/170 on 26 January), the largest being an M2.5/1n on 23 January. This region also produced an M1/1n flare on 24/0327Z with strong radio bursts including a 12,000 sfu burst on 410 Mhz. Region 266 grew steadily in size and complexity early in the period. On 23 January, it developed a beta-gamma magnetic configuration and maintained this moderate complexity through the remainder of the period. Regions 269 (S07, L=307, class/area Dso/130 on 25 January) and 260 contributed to the moderate solar activity levels with single minor M-class flares on 21 and 22 January respectively. For flare times and magnitudes please refer to the Energetic Event and Flare List. The period ended with low solar activity, highlighted by a C4 flare with moderate centimetric bursts from Region 268 (N14, L=001, class/area Dao/130 on 26 January). Solar wind data were available from the NASA Advanced Composition Explorer (ACE) spacecraft for most of the summary period. On 20 January, solar wind velocity increased to near 780 km/s due to a northern extension of a southern coronal hole rotating into a geo-effective position. By 22 January, speed decreased, but remained elevated at over 500 km/s. The speed began to increase again late on the 22nd due to the onset of another high-speed coronal hole stream and peaked at near 800 km/s on 24 January. We observed a gradual decrease since, to just over 500 km/s by the end of the period. The Bz component of the interplanetary magnetic field ranged from +5 to –8 nT. There were occasional, mostly short-lived periods of sustained southward Bz. 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 were at moderate levels on 20 January, but exceeded high levels each day for the remainder of the period. The geomagnetic field was at quiet to minor storm levels. Minor storm conditions were observed on 20, 22-23, and 25 January due to high-speed coronal hole flow. The most active periods occurred on 25 January when the solar wind speed increased to near 800 km/s and Bz was sustained southward for almost seven hours. Major storm levels were observed at higher latitudes during this period. Forecast of Solar and Geomagnetic Activity 29 January - 24 February 2003 Solar activity is expected to be mostly low with occasional moderate levels during the period. The active regions that produced the M-class flares during this past week are all in decay. Further M-class activity from these regions is unlikely. No greater than 10 MeV proton events are expected during the forecast period. The greater than 2 MeV electron flux is expected to reach high levels on 01 – 02 February and again on 16 – 22 February due to recurring coronal holes. The geomagnetic field is expected to be at quiet to isolated major storm levels during the period. Isolated active conditions are possible on 30 – 31 January due to a small recurring coronal hole. Minor storming with isolated major storm conditions are possible on 15 -22 February due to a returning equatorial coronal hole. .