Solar Terrestrial Activity Report [Image] Last update April 14, 2000 at 03:55 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update April 2, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update April 2, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update April 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 April 13. Solar wind speed ranged between 337 and 392 km/sec. Solar flare activity was low. Solar flux was 164.0, the planetary A index was 8 (3-hour K indices: 3331 1221, Boulder K indices: 1321 0100). Region 8948 decayed and was quiet most of the day. Occasional C flares are possibly from this region. Region 8949 was quiet and stable, as were regions 8951, 8953 and 8954. Region 8955 developed slowly and has minor M class flaring potential. Region 8956 was quiet and stable. Region 8958 decayed slowly and could become spotless today. Region 8959 was quiet and stable. New region 8960 emerged in the northwest quadrant. New region 8961 emerged in the southeast quadrant. New regions 8962 and 8963 rotated partly into view at the northeast limb. Flares and CMEs A total of 3 C flares were recorded on April 13. Region 8948 produced a C2.9 flare at 00:23 UTC. The other two C flares were both C1 flares and optically unaccounted. The background x-ray flux is at the class B6 level. Coronal holes A small and well placed coronal hole near the equator was in a geoeffective position on April 12. Another well placed and fairly small coronal hole will rotate into a geoeffective position on April 18-19. Forecast The geomagnetic field is expected to be quiet to unsettled on April 14. A weak coronal stream could start on April 15 and will likely result in unsettled to active intervals. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair to 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 8944 20000401 N08W87 plage 8945 20000401 S23W81 plage 8948 20000404 11 S15W49 0110 DAO beta-gamma 8949 20000405 4 S19W27 0100 CAO 8951 20000407 6 N12W03 0100 CSO 8952 20000407 S23W30 plage 8953 20000409 4 S15E20 0060 CSO 8954 20000410 4 N30E29 0010 BXO 8955 20000410 11 S22E46 0380 EKO 8956 20000410 4 N13E11 0020 BXO 8957 20000410 S12W53 plage 8958 20000411 2 N16E42 0010 AXX 8959 20000412 7 S17E14 0090 DAO 8960 20000413 3 N19W15 0010 BXO 8961 20000413 2 S25E07 0010 BXO 8962 20000413 1 N21E76 0070 HSX 8963 20000413 1 N15E74 0060 HAX Total number of sunspots: 60 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.03 126.3 69.1 83.8 (-0.8) 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 (108.6 predicted, +6.3) 1999.11 191.5 132.7 (112.3 predicted, +3.7) 1999.12 169.8 86.4 (111.9 predicted, -0.4) 2000.01 158.1 90.2 (112.7 predicted, +0.8) 2000.02 174.1 112.3 (116.2 predicted, +3.5) 2000.03 208.2 138.2 2000.04 189.7 (1) 86.1 (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]