:Product: Weekly Highlights and Forecasts :Issued: 2004 Jan 20 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 12 - 18 January 2004 Solar activity ranged from very low to high levels. On 12 – 15 January, activity was at low levels with very low levels observed on 16 January. Region 537 (N05, L= 009, class/area Dkc/240 on 12 January) exhibited slow decay throughout the period and simplified from a beta-gamma-delta magnetic configuration to a simple beta on 17 January. Region 536 (S12, L=074, class/area Ekc/600 on 09 January), produced six C-class flare on 12 – 13 January before it rotated beyond the west limb on 14 January. New Region 540 (S11, L=285, class/area Eao/500 on 13 January) rotated onto the disk on 12 January and has maintained good areal coverage with evidence of considerable magnetic polarity mixing. The most significant activity of the period came from Region 540 late in the period. On 17 January, this region produced an M5 flare at 1750 UTC with an associated Type II radio sweep (784 km/s), a large 245 Mhz radio burst (270,000 sfu) and a partial halo CME off to the south. The period ended on 18 January with Region 540 producing an M1/1n flare at 0017 UTC with an associated Type II radio sweep (1000 km/s). At the time of this report (20 January) Region 540 continues to produce high level activity with an M6/2n at 0743 UTC with an associated halo CME. Solar wind data were available from the NASA Advanced Composition Explorer (ACE) spacecraft during most of the summary period. The period began on 12 January with solar wind speeds near 500 km/s. A transient passage was observed on 13 January with wind speeds increasing to near 600 km/s for about a twenty-four hour period. Wind speed began a gradual and steady increase on 15 January reaching 650 km/s by 16 January due to a coronal hole high speed stream. The period ended with wind speeds still elevated near 550 – 600 km/s. There were no greater than 10 MeV proton events at geosynchronous orbit during the summary period. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels for most of the period. High levels were observed on 12 – 13, 15, and 17 – 18 January. The geomagnetic field ranged from quiet to minor storm levels. Activity was at quiet to unsettled levels on 12 – 14 January except for a nine-hour period of active conditions late on 13 January. Active conditions were observed on 15 January. The onset of a coronal hole high speed stream produced isolated minor storm levels on 16 January and unsettled to active levels on 17 – 18 January. Forecast of Solar and Geomagnetic Activity 21 January - 16 February 2004 Solar activity is expected to be at low to moderate levels with a chance of major flare activity. Region 540 has the potential for major flare activity through 25 January. Activity in the mid to latter half of the period is expected to be at low levels with a chance of moderate activity due to the return of Regions 536 537 and 540 to the visible disk. There is a slight chance for a greater than 10 MeV proton event during the period in association with a major flare from one of three active regions. The greater than 2 MeV electron flux at geosynchronous orbit is expected to reach high levels on 28 – 29 January and again on 31 January – 09 February due to recurrent coronal holes. Geomagnetic activity is expected to range from quiet to minor storm levels with a chance of isolated major storm levels. A second recurrent coronal hole is expected to return on 27 – 28 January resulting in active to minor storm levels. The large transequatorial coronal hole of the last few rotations has broken up into several smaller coronal holes. This series of recurrent coronal holes is due to return on 30 January – 07 February and is expected to produce minor storm level activity with a chance of isolated major storm levels. The coronal hole of last week is due to return on 11 – 14 February, with minor storm levels possible.