:Product: Weekly Highlights and Forecasts :Issued: 2003 Nov 05 2100 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 04 November - 27 October 2003 Solar Activity ranged from moderate to high levels. Activity on 27 – 29 October was at high levels with most of the activity originating in Region 486 (S16, L=285, class/area Fkc/2610 on 29 October) and Region 488 (N08, L=289 class/area Fkc/1750 on 30 October). An M6/Sf occurred on 27 October from Region 486. On 28 October, Region 486 produced one of the largest flares of this solar cycle, an X17/4B proton flare peaking at 1110 UTC on the 28th. This flare had intense radio bursts including a 245 MhZ burst near 500,000 sfu, a Tenflare of 13,000 sfu and Type II (1250 km/s) and Type IV radio sweeps. An extremely fast (near 2000 km/s), earthward directed halo CME was observed on SOHO/LASCO imagery. On the 29th, Region 486 produced another major flare, an X10 at 29/2049Z. Once again, intense radio emissions accompanied this flare, including a 360,000 sfu burst at 245 MHz, a 2500 sfu Tenflare, and strong Type II/IV radio sweeps. A very fast (over 1900 km/s) earth-directed full halo CME was observed on LASCO imagery. Throughout the period Region 486 maintained its tremendous size and magnetic complexity, with strong delta configurations. On 29 October, the sunspot area of Region 486 grew to 2610 millionths making it the largest spot group observed to date in this solar cycle. Moderate level activity was observed on 30 October – 01 November due to minor M-class flares from Regions 486 and 488. Region 484 (N04, L=354, class/area Ekc/1750 on 22 October) rotated beyond the west limb on 30 October. Region 488 developed very rapidly near center disk on 27 October and exhibited rapid growth over the next three days, reaching 1750 millionths in size. Despite its impressive size activity from Region 488 consisted of mainly minor M-class events. At the end of the period Region 486 produced another major event, an X8/2b flare at 1725 UTC on 02 November. This flare was associated with a Tenflare of 7,700 sfu, a 245 MhZ radio burst of 24,000 sfu, and Type II (1691 km/s) and Type IV (70 min.) radio sweeps. LASCO imagery also indicates and halo CME associated with the X8. At the time of this report issue (04 November) Regions 486 and 488 produced a couple of X-class event on 03-04 November; an X3/2b from Region 486 on the 3rd, an X2/2f from Region 488 on the 3rd, and an X17-plus at 1956 UTC (saturation ended, exact peak not known) on the 4th. The X17-plus flare saturated the GOES X-ray instrument for 11 minutes. Further detail will be provided in next week’s summary. Solar wind data were partially available from the NASA Advanced Composition Explorer (ACE) spacecraft during the summary period. The large proton events mentioned below contaminated the SWEPAM and EPAM instruments on board ACE making the data unreliable on 28 – 30 October and again on 02- 03 November. Solar wind events during the period were closely associated with geomagnetic activity and are summarized below with the geomagnetic activity. A number of proton events occurred this period. First, the proton event that began last summary period on 26 October, and ended at 27/1910 UTC. Second, the X17 flare from the 28th produced a greater than 10 MeV and greater than 100 MeV proton event. The greater than 100 MeV event began at 18/1150 UTC, reached a peak value of 186 pfu at 29/0015 UTC, and ended at 31/0145 UTC. The greater than 10 MeV event began at 28/1240 UTC, max value of 29,500 pfu at 29/0615 UTC, and ended at 01/1310 UTC. This 10 MeV proton event is the second largest, to date in this solar cycle. A secondary enhancement of greater than 10 MeV and 100 MeV protons was observed late on 29 October due to the X10 flare. The greater than 10 MeV flux increased to a secondary maximum of 3300 pfu at 30/1935 UTC and the greater than 100 MeV flux increased to 110 pfu at 29/2310 UTC. Third, a greater than 10 MeV proton flux exceeded event threshold at 02/1105 UTC due to the M3 flare from Region 486 and reached a peak value of 30 pfu at 1415 UTC. Before this proton event ended the X8 flare at 1725 on the 2nd increased the greater than 10 MeV proton flux to new maximums. Greater than 10 MeV flux reached 1570 pfu at 03/0815 UTC and the event is still in progress as of the time of this report (04 November). The greater than 100 MeV proton flux due to the X8 event began at 02/1740 UTC, reached a peak value 49 pfu at 02/1905 UTC, and ended at 03/1720 UTC. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels on 01 – 02 November. From 28 – 31 October the 2 MeV data from GOES-11 and GOES-10 were unreliable due to solar radiation contamination if the instrument. Geomagnetic activity ranged from quiet to severe storm levels. Activity was at quiet to active levels from 27 – 28 October. A shock and CME associated with the X1 flare on the 26th passed the ACE spacecraft at around 0130 UTC on 28 October. Solar wind speed rose to near 800 km/s, but Bz stayed northward and the geomagnetic field was at active levels. The powerful shock and CME from the X17/4b flare on the 28th, passed ACE at 0559 UTC, and impacted Earth's magnetic field at 0613 UTC on 29 October with a very strong sudden impulse. The sudden impulse measured 140 nT on the Boulder magnetometer. The transit time for this CME was around 19 hours, making it one of the fastest on record. Strong southward IMF Bz initiated severe (K9) storming at middle and high latitudes. Mostly northward Bz occurred following the initial shock, however major to severe storming persisted (K7). A sharp southward turn in the Bz occurred at around 1800 UTC on the 29th ending the day with severe storming (K8-9). The intense geomagnetic storming continued through the first half 30 October. Severe (K8-9) levels were observed during the 00 – 06 UTC period. A short-lived "lull" (K5-6) in activity preceded the onset of another severe geomagnetic storm. The very fast CME from the X10 flare at 29/2049 UTC impacted the magnetic field at around 1600 UTC on 30 October – another fast 19-hour transit from Sun to Earth. GOES-10, 11, and 12 geosynchronous satellites experienced magnetopause crossings lasting over three hours in duration. Sustained southward IMF Bz in the -15 to –30 nT and a total IMF measurement near 40 nT as measured at ACE produced severe storming after 1600 UTC on 30 October. Bz rotated northward early on 31 October and by midday on 31 October geomagnetic activity had declined to active levels. Activity on 01 – 02 November was predominantly at unsettled to active levels due to the declining but still elevated solar wind speed (600 – 1000 km/s). Forecast of Solar and Geomagnetic Activity 05 November - 01 December 2003 Solar activity is expected to range from low to high levels. Regions 486 and 488 have the potential for M and X-class activity until they rotate beyond the west limb on 04 – 05 November. Regions 484, 486, and 488 are due to return to the visible disk on 12, 17, and 18 November, respectively. Activity after the 12th is expected to range from low to high levels. Currently a greater than 10 MeV proton event is in progress and enhanced due to the X17-plus flare, and is expected to end early on 07 November. Additional proton producing flares are possible until Regions 486 and 488 are well beyond the west limb, after 06 November. Proton events are possible once Region 484 returns to the visible disk on 12 November. The greater than 2 MeV electron flux at geosynchronous orbit is expected to reach high on 12 – 19 November due to a large returning coronal hole The geomagnetic field is expected to range from quiet to major storm levels during the period. A CME form the X17-plus event is expected to arrive on day two or three of the period with major storm levels possible. A large coronal hole is due to return on 09 – 18 November and is expected to produce major storm levels. Major flare activity from returning Region 484, 486, and 488 may produce severe storm levels during the second half of the period.