Solar Terrestrial Activity Report [Image] Last update May 9, 2000 at 01:20 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update May 2, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update May 2, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update May 2, 2000)] [Historical solar and geomagnetic data charts 1954-2000 (last update April 12, 2000)] Recent development The geomagnetic field was quiet to unsettled on May 8. Solar wind speed ranged between 347 and 411 km/sec. Solar flare activity was low. Solar flux was 137.0, the planetary A index was 6 (3-hour K indices: 2012 2213, Boulder K indices: 2021 1313). Region 8980 was quiet and stable. Region 8981 decayed into spotless plage. Regions 8983, 8984, 8986 and 8987 were quiet and stable. Region 8988 decayed into spotless plage. Region 8989 developed slowly and should be capable of C class flaring. Region 8990 developed slowly and has fairly tight magnetic gradients. Further C class flares are likely and there is a small possibility of a minor M flare. New region 8991 rotated partly into view at the northeast limb, the region could produce C flares and perhaps a minor M flare. Flares and CMEs A total of 5 C flares were observed on May 8. Region 8990 was the source of a C1.2 flare at 06:59, a C4.2 flare at 10:50 and a C1.3 flare at 17:22 UTC. A large filament eruption across the central meridian in the southern hemisphere was in progress at 06:12 UTC in LASCO EIT images. A partial halo coronal mass ejection was observed from 06:48 UTC in LASCO C2 images. There is a possibility of a terrestrial impact on May 11. The background x-ray flux is at the class B4 level. Coronal holes A small well placed coronal hole in the southern hemisphere was in a geoeffective position on May 8-9. Forecast The geomagnetic field is expected to be quiet to unsettled on May 9-10. There is a chance of minor effects from a coronal stream on May 11-12. A CME could impact Earth on May 11 causing unsettled to minor storm intervals. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair. Coronal holes (1) Coronal mass M and X class flares (3) ejections (2) [Coronal hole indicator][CME indicator] [M and X class flare indicator] 1) Effects from a coronal hole could reach earth within the next 5 days. 2) Material from a CME is likely to impact earth within 96 hours. 3) There is a possibility of either M or X class flares within the next 48 hours. Green: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% probability. Active solar regions (Recent map) Solar Date Actual no. Location at region numbered sunspots midnight Area Classification Comment 8979 20000428 N21W83 plage 8980 20000428 5 S15W61 0010 BXO 8981 20000501 S22W56 plage 8982 20000503 S19W45 plage 8983 20000504 8 N25E06 0020 BXO 8984 20000505 4 S13W28 0000 BXO 8985 20000505 N12E12 plage 8986 20000505 11 S23E21 (??) 0020 BXO 8987 20000507 4 N12W03 0010 BXO 8988 20000507 N08W17 plage 8989 20000507 9 N16E25 0070 DAO 8990 20000507 8 N14E48 0050 DSO 8991 20000508 2 N16E71 0020 AXX Total number of sunspots: 51 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.04 117.2 63.9 85.5 (+1.7) 1999.05 148.4 106.3 90.5 (+5.0) 1999.06 169.8 137.7 93.1 (+2.6) 1999.07 165.6 113.5 94.5 (+1.4) 1999.08 170.7 93.7 97.4 (+2.9) 1999.09 135.7 71.5 102.3 (+4.8) 1999.10 164.8 116.7 107.7 (+5.4) 1999.11 191.5 133.2 (109.8 predicted, +2.1) 1999.12 169.8 84.6 (108.2 predicted, -1.6) 2000.01 158.1 90.2 (108.6 predicted, +0.4) 2000.02 174.1 112.3 (112.0 predicted, +3.4) 2000.03 208.2 138.2 (115.8 predicted, +3.8) 2000.04 184.2 125.3 2000.05 138.4 (1) 30.4 (2) 1) Running average based on the daily 20:00 UTC solar flux value at 2800 MHz.. 2) Unofficial, accumulated value. The official value is typically 25-40% less. This report has been prepared by Jan Alvestad. It is based partly on my own observations and interpretations, and partly on data from sources in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]