:Product: Weekly Highlights and Forecasts :Issued: 2005 Jan 18 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 10 - 16 January 2005 Solar activity ranged from very low to high levels. The summary period began with very low to low levels on 10 – 13 January and increased rapidly to moderate to high levels on 14 – 17 January due to the rapid development of Regions 718 (S07, L=197, class/area, Fki/360 on 15 January) and 720 (N13, L=179, class/area, Dkc/1620 on 15 January). Region 718 exhibited moderate growth both in area and sunspot number, and produced two low-level M-class flares on 14 and 15 January. New Region 720 was the largest and most impressive group on the visible disk. The region rotated quietly onto the disk as a simple beta magnetic sunspot group on the 10th, grew rapidly in both area and sunspot count on 12 and 13 January, and ended the summary period as a large, magnetically complex sunspot region. From 14 - 17 January, Region 720 produced eleven M-class and three X-class flares of which three were significant. The first of these significant events was a long duration M8.6/Sf Tenflare (3000 sfu) at 15/0638 UTC with associated Type II (1292 km/s) and Type IV radio sweeps. SOHO/LASCO imagery detected a fast, full-halo CME with this event. Later in the day, Region 720 produced an X2.6/3b at 15/2302 UTC. This flare was associated with significant radio output including a 6400 sfu Tenflare and a Type II (1151 km/s) radio sweep. An even faster asymmetric, full-halo CME was detected with this event. The third significant event, though occurring outside of the summary period, merits discussion. At 17/0952 UTC, Region 720 produced an X3.8/2f Tenflare (12,000 sfu) with very significant discrete radio output and Type II (1568 km/s) and Type IV radio sweeps. Although the period ended with Region 720 remaining a large and magnetically complex sunspot group, some restructuring of the sunspots were apparent following the X3.8 flare. The period began with generally quiet solar wind plasma and IMF conditions. An increase in solar wind density and changes in the IMF structure late on 11 January indicated the arrival of a co-rotating interaction region (CIR) and coronal hole high speed stream. Solar wind gradually increased to over 750 km/s by midday on the 13th, before gradually declining to near 600 km/s by late on 14 January. Another short-lived high speed stream occurred on 15 January with solar wind speed increasing to near 750 km/s. The onset of transient flow from the strong solar events and CMEs of 15 January began midday on 16 January. The initial onset of transient flow was weak. The stronger, more significant activity arrived early on 17 January. Solar wind speed exceeded 800 km/s and periods of sustained southward Bz were observed. A greater that 10 MeV proton enhancement began following the long duration M8.6 flare on 15 January; however, the 10 pfu event threshold was not exceeded during this enhancement. A greater than 10 MeV proton event began on 16/0210 UTC following the X2.6 flare late on the 15th. The peak flux following this flare was 365 pfu at 16/1840 UTC. The period ended with the protons in gradual decline. At the time of this writing, a second stronger injection of protons occurred following the X3.8 flare and CME that occurred early on the 17th. This new intensification included protons at greater than 100 MeV. The proton event remains in progress. The peak flux so far at greater that 10 MeV was 5040 pfu on the 17th. The greater than 100 MeV protons peaked at 28 pfu, also on the 17th. The greater than 2 MeV electron flux at geosynchronous orbit was at high levels from 13 – 16 January. The geomagnetic field ranged from quiet to major storm levels with an isolated period of severe storming observed at higher latitudes. Quiet to active, with some minor high latitude storming periods, were experienced on 10 – 11 January, as the IMF Bz fluctuated between +/- 5 nT. By early on the 12th, activity levels generally increased to unsettled to minor storming with isolated major to severe storming at higher latitudes, due to the onset of a geoeffective coronal hole high speed wind stream. Prolonged periods of southward Bz produced occasional active levels from late on the 12th through early on the 15th. Isolated minor to major storming was observed midday on 15 January due to a short-lived high speed coronal hole wind stream. Activity declined to mostly quiet to unsettled until midday on the 16th when activity increased at higher latitudes to unsettled to isolated minor storming following the onset of transient flow from the first of the CMEs. Forecast of Solar and Geomagnetic Activity 19 January - 14 February 2005 Solar activity is expected to be at moderate to high levels through 22 January when Region 720 is due to rotate around the west limb. Thereafter, very low to low conditions are expected through 05 February with a chance of isolated M-class activity after the 5th due to the return of old Region 720 (N13, L=178). A greater than 10 MeV proton event is in progress and is expected to persist through 21 January. Further intensifications of the existing event are possible with additional major flare activity from Region 720. Proton flux levels are expected to return to background conditions by the end of January and are expected to remain so for the balance of the forecast period. The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at high levels on 19 – 21 January, 30 January to 02 February, and 08 – 11 February. The geomagnetic field is expected to range from quiet to severe storm levels. Early in the forecast period, minor to severe storming is expected as effects from the 17 January CME are due to arrive. Coronal hole high speed wind streams are expected to produce unsettled to active with occasional minor storm periods on 29 - 31 January and 07 – 08 February. Otherwise, expect quiet to unsettled conditions.