:Product: Weekly Highlights and Forecasts :Issued: 2003 Feb 04 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 27 January - 02 February 2003 Solar activity was at very low to moderate levels. The period began at low levels, highlighted by a long duration C2 flare on 27 January associated with a filament eruption from near S19W19. Low levels persisted through the 29th with just occasional minor C-class flares observed. All active regions on the visible disk appeared to be stable or in decay, resulting in very low conditions on 30 January. However, the most energetic event of the period occurred on the 30th when a large filament erupted from the north-central disk and produced an earthbound coronal mass ejection (CME). We returned to low levels on the 31st with considerable activity on the SE limb, indicating that a new active region was rotating onto the visible disk. This new region was the likely source of minor C-class activity. A prominence was observed erupting off the Northwest limb late on the 31st, which had an associated Type II radio sweep with a shock velocity of 500 km/s. New Region 276 (S14, L=161, class/area Eai/240 on 02 February) rotated further into view on 1 Feb and quickly brought activity levels to moderate, with an M1 flare at 0905 UTC. This region was the dominant source of activity for the remainder of the period producing several C-class flares, the larges being a C9/Sf late on 1 February. For flare times and magnitudes please refer to the Energetic Event and Flare List. Solar wind data were available from the NASA Advanced Composition Explorer (ACE) spacecraft for most of the summary period. The period began in a diminishing high-speed coronal hole stream. Solar wind speed was elevated between 500 – 600 km/s early, but had declined to more nominal speeds of 400 – 450 km/s by the 28th. Occasional sustained periods of southward Bz in the interplanetary magnetic field occurred on the 28-29th. Solar wind speed increased on the 30th with the onset of another coronal hole. Speed gradually increased to over 600 km/s on the 31st before the effects of the coronal hole started to wane. A dramatic increase in solar wind speed to over 800 km/s was observed to begin at around 1300 UTC on the 1st as the CME observed on 30 January impacted the ACE spacecraft. A marked increase in density, temperature and total magnetic field also occurred with this transient passage. The Bz component of the interplanetary magnetic field was initially northward as the CME passed ACE, but periods of southward Bz were observed late on the 1st through the 2nd. Speed had returned to near 450 km/s by the end of the period. 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 reached high levels on 27 and 29 January and again on 31 January through 1 February. The geomagnetic field was at quiet to major storm levels. Occasional active periods occurred on the 28th and 29th as the Bz component of the interplanetary magnetic field rotated southward for extended periods. Active to minor storm periods were observed on 30 – 31 January with the onset of high-speed coronal hole stream. Minor to major storm periods occurred late on the 01 February through the 2nd following the passage of the 30 January filament eruption and CME. Forecast of Solar and Geomagnetic Activity 05 February - 03 March 2003 Solar activity is expected to be mostly low with occasional moderate levels during the period. Region 276 has potential for M-class activity early in the period. There are also indications of new active regions rotating around the east limb in the next few days. 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 15 – 19 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 05-06 February due to a small recurring coronal hole. Minor storming with isolated major storm conditions are possible on 14 -18 February due to a returning equatorial coronal hole. .