Solar Terrestrial Activity Report [Image] Last update May 5, 2000 at 04:15 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 4. Solar wind speed ranged between 408 and 513 km/sec. Solar flare activity was high. Solar flux was 134.5, the planetary A index was 8 (3-hour K indices: 2123 3322, Boulder K indices: 2233 3322). Regions 8976, 8977 (which has rotated off the visible disk early on May 5), 8978, 8980 and 8981 were quiet and stable. Region 8982 could produce further C flares. New region 8983 at the northeast limb was finally numbered. Flares and CMEs A total of 2 C flares and 2 M flares were recorded on May 4. Region 8982 produced a C1.2 flare at 19:19 UTC. Region 8970 (just behind the southwest limb) was the source of both M flares, first an M2.8/1N flare at 04:51, then a major flare, an M6.8 event at 11:08 UTC. A large coronal mass ejection was observed off the southwest limb in association with the major flare. The background x-ray flux is at the class B4-B5 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to unsettled on May 5-7. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor. 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 8976 20000428 1 S12W74 0030 HRX 8977 20000428 1 S13W91 0050 HSX 8978 20000428 6 N20W74 0040 BXO 8979 20000428 N21W31 plage 8980 20000428 2 S15W08 0010 AXX 8981 20000501 12 S22W10 0030 CRO 8982 20000503 10 S20E07 0020 BXO 8983 20000504 3 N25E58 0050 CAO Total number of sunspots: 35 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.04 117.2 63.9 85.4 (+1.6) 1999.05 148.4 106.3 90.4 (+5.0) 1999.06 169.8 137.7 93.0 (+2.6) 1999.07 165.6 113.5 94.4 (+1.4) 1999.08 170.7 93.7 97.5 (+3.1) 1999.09 135.7 71.5 102.3 (+4.8) 1999.10 164.8 116.4 107.7 (+5.4) 1999.11 191.5 132.7 (109.8 predicted, +2.1) 1999.12 169.8 86.4 (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 2000.05 145.6 (1) 14.4 (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]