:Product: Weekly Highlights and Forecasts :Issued: 2002 Mar 05 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 25 February - 03 March 2002 Solar activity was at low to moderate levels. Activity was at moderate levels on 25 February with an optically uncorrelated M1.0 flare. Region 9830 (S20, L= 135, class/area Fkc/530 on 20 February) was in a decay phase at the start of the summary period. On 25 February Region 9830 simplified in magnetic complexity from a beta-gamma-delta to a beta-gamma configuration and on 26 February rotated beyond the west limb. Activity also at moderate levels on 27 and 28 February with the largest event an M2.2 flare associated with an eruptive prominence (S24W90) off the southwest limb at 28/0012 UTC. The source of this event was mostly likely Region 9839 (S18, L=111, class/area Eao/250 on 27 February), which was transiting the west limb at the time. This region reached it's maximum size and complexity on 27 February as it approached the west limb and taking into account limb effects, it is uncertain as to whether or not it was in a decay phase as it rotated beyond the west limb. Region 9845 (N18, L= 016, class/area Fki/390 on 03 March) had shown gradual growth throughout the period and developed a beta-gamma magnetic configuration on 01 March. This region also produced a C9 flare at 01/0012 UTC, as determined by SOHO/LASCO imagery. Two Type II Radio Sweeps were recorded on 01 March at 0214 UTC (1200 km/s) and 0542 UTC (742 km/s). The most likely source of the 0214 UTC Type II was Region 9839 beyond the southwest limb. The most likely source of the 0542 UTC Type II was a C7/Sf flare at 01/0530 UTC from Region 9848 (S20, L=029, class/area Dso/060 on 26 February). On 02-03 March activity was low with only minor C-class flares. On 02 March a large eruptive prominence was observed lifting off the southeast limb at 02/1415 UTC with an associated CME seen by LASCO C2 imagery. No earth directed component was noted. Solar wind data were available from NASA Advanced Composition Explorer (ACE) spacecraft for most of the summary period. A weak shock passage was detected at ACE early on 28 February and resulted in a solar wind speed increase to approximately 400 km/s. Wind speed then decreased to a range of 300-350 km/s by 03 March. Late on 03 March a sector boundary crossing was observed and wind speed increased with peak values around 400 km/s. There were no proton events at geosynchronous orbit during the period. The greater than 2 MeV electron flux at geosynchronous orbit was at normal levels. The geomagnetic field was at quiet to unsettled levels early in the period. A 28 nT sudden impulse was recorded at the Boulder magnetometer at 28/0500 UTC and resulted in active to minor storm conditions on 28 February. This activity was due to the weak CME shock passage mentioned above. A Sustained southward IMF early on 01 March resulted in minor storm levels at mid latitudes and active conditions elsewhere for the first 3 hour period on 01 March. Conditions returned to quiet to unsettled later in the day on 01 March and throughout 02 March. High speed stream effects from a recurrent coronal hole commenced on 03 March resulting in quiet to active conditions. Forecast of Solar and Geomagnetic Activity 06 March - 01 April 2002 Solar activity is expected to be low to moderate levels. On 07 March, early in the forecast period, old Region 9825 is due to return and isolated M-class flares are possible. Old Region 9839 is due to return on 27 March and may result in isolated M-class flares. The greater than 2 MeV electrons flux may reach high level during 06 - 08 March due to high speed stream effects. Otherwise normal to moderate levels are expected. There will be a slight chance of a proton event during the period, with the return of old Region 9825 early in the period and the return of old Region 9839 later in the forecast period. The geomagnetic field is expected to be at active levels for the first day or two of the forecast period due to high speed stream effects. Quiet to unsettled levels should prevail for the remainder of the period. The return of the large coronal hole late in the period may produce active conditions. .