:Product: Weekly Highlights and Forecasts :Issued: 2003 Nov 12 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 11 - 03 November 2003 Activity ranged from very low to high levels. Region 486 (S16, L=285, class/area Fkc/2610 on 29 October) continued to produce major flare activity and Region 488 (N08, L=289, class/area Fkc/1750 on 30 October) contributed a few major flares of its own. High level activity was observed on 03 November with an X2/Sf at 0130 UTC and an X3/2b at 0955 UTC, both from Region 488. Both of these flares were associated with Tenflares, 245 Mhz radio bursts and Type II and Type IV radio sweeps. The most significant flare of the period occurred on 04 November from Region 486. An X-ray flare began at 1931 UTC and saturated the GOES X-ray sensor at the X17.4 level for 12 minutes (1944 to 1956 UTC). Analysis of available data yields an estimated peak X-ray flux of X28 with a peak time at 1950 UTC, making it one of the largest flares ever measured on GOES/XRS. Associated with the X28 were intense radio busts at all frequencies, including a Tenflare of 20,000 sfu, a 245 Mhz radio burst of 4,800 sfu, and Type II and Type IV radio sweeps. Indications of an extremely fast moving (2301 km/s) full halo CME were seen on LASCO imagery. By 05 November, Region 486 rotated beyond the west limb but still produced an M5/Sf at 1052 UTC. Activity for the remainder of the period, 06 – 09 November, decreased dramatically to very low levels after nearly three weeks of intense solar activity. A full halo CME was observed in LASCO imagery late on 06 November, but was determined to be back-sided. A combination of observed CMEs and long duration low levels X-ray enhancements suggest continued activity from the Regions 484, 486, and 488 on the back-side. Solar wind data were available from the NASA Advanced Composition Explorer (ACE) spacecraft during most of the summary period. A CME shock from the X8 on 02 November passed the ACE spacecraft at 0600 UTC on 04 November with solar wind speed increasing to over 800 km/s and Bz dropping to -20 nT in the southward direction. Bz was southward for a short period then turned north for the remainder of the day. Solar wind speed gradually declined to 500 km/s by 06 November when a second CME shock was observed. The CME shock from the X28 flare on 04 November arrived at ACE around 1900 UTC on 06 November with solar wind speed increasing to 625 km/s. Bz dropped briefly to –10nT and Bt measured 15 nT for a brief period. Bt declined below 10 nT by the end of the day on 06 November. Toward the end of the period a corotating interaction region was observed at ACE on 08 November with solar wind speed gradually rising through 08 – 09 November and Bz exhibiting the north-south oscillating signature of a coronal hole high speed stream. As the period began a greater than 10 MeV proton event was in progress due to the M3 flare on 01 November and the X8 flare on the 2nd. This event reached a peak value of 1570 pfu at 02/0815 UTC and was in decline until 04 November. As proton flux decreased to near threshold levels, an enhancement in proton flux level was observed at 04/2225 UTC due to the X28 flare. This X28 enhancement of 10 MeV proton flux reached a peak value of 353 pfu at 05/0600 UTC. The 10 MeV proton event finally dropped below threshold levels and ended at 07/1230 UTC. The X8 and X28 flares also produced greater than 100 MeV proton events. The X8, 100 MeV proton event began last period at 02/1740 UTC, reached a peak value of 49 pfu at 02/1905 UTC, and ended at 03/1720 UTC. The X28, greater than 100 MeV proton event began at 05/0535 UTC, reached a peak value of 1.3 pfu at 05/0540 UTC, and ended at 05/0705 UTC. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels on 03 – 04 November. Late on 05 November and early on 06 November, greater than 2 MeV electron flux data from GOES-11 and GOES-10 were unreliable due to solar radiation contamination of the EPS instrument. Geomagnetic activity ranged from quiet to severe storm levels. The period began with unsettled to isolated active conditions on 03 November. A shock passage occurred at the NASA/ACE satellite at approximately 0600 UTC on 04 November due to the arrival of a CME from the X8 flare on 02 November. A sudden impulse of 72 nT was observed on the Boulder magnetometer at 04/0627 UTC. The shock produced minor storm levels during the 06-09 UTC period. A brief period of southward Bz after the shock resulted in one period of severe storm levels from 09-12 UTC. Bz then turned northward and remained north though most of the day (04 November) producing only unsettled to active conditions. Quiet to unsettled activity was observed on 05 November and for most of 06 November. Late on 06 November, a shock from the X28 flare from 04 November arrived at 1937 UTC, producing a 31nT sudden impulse on the Boulder magnetometer. Activity from this CME consisted of one isolated period of minor storm levels followed by one period of active levels. Activity was at quiet to unsettled levels on 07 – 08 November. The period ended on 09 November with active to major storm levels due to a co-rotating interaction region marking the onset of a coronal hole high speed stream. Forecast of Solar and Geomagnetic Activity 12 November - 08 December 2003 Solar activity is expected to range from low to high levels. Activity is expected to be low to moderate until Region 484 returns to visible disk on 12 November. Isolated high level activity is possible after that. On 17 – 18 November, Regions 486 and 488 are due to return to the visible disk with continued isolated high level activity possible. Proton producing flares 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 – 20 November due to a large returning coronal hole. The geomagnetic field is expected to range from quiet to major storm levels. A large coronal hole is due to return to a geoeffective position on 12-20 November and is expected to produce minor to major storm levels. After 15 November, with the return of old Region 484, geomagnetic activity may increase in association major flare and CMEs.