Solar Terrestrial Activity Report [Image] Last update August 18, 2000 at 02:20 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update August 4, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update August 4, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update August 4, 2000)] [Historical solar and geomagnetic data charts 1954-2000 (last update August 10, 2000)] Recent development The geomagnetic field was quiet to slightly active on August 17. Solar wind speed ranged between 332 and 422 km/sec. Solar flare activity was low. Solar flux was 177.1, the planetary A index was 11 (3-hour K indices: 2441 2332, Boulder K indices: 2344 1201). Region 9123 was quiet and stable. Region 9124 decayed slightly and was quiet. Region 9125 decayed slowly and could produce occasional C class flares and perhaps a minor M class flare. Region 9127 was mostly unchanged and quiet. Occasional C class flares are possible. Region 9128 decayed slowly and was quiet. Region 9129 developed slowly and could produce C class flares. Region 9131 did not change significantly and could produce occasional C class flares. Region 9132 decayed slowly and was quiet. Region 9133 was quiet and stable. Region 9134 was spotless early in the day but reemerged with some spots later on. Region 9135 developed at a moderate pace and could produce C and minor M class flares. New region 9136 emerged in the northeast quadrant near the central meridian. Flares and CMEs A total of 6 C class events were recorded on August 17. Region 9131 produced a C4.9/1N flare at 08:37 UTC. Region 9125 generated a C1.2 flare at 12:41 UTC. Region 9136 was the source of a C1.1 flare at 17:09 UTC. The background x-ray flux is at the class B5 level. Coronal holes A well defined coronal hole in the southern hemisphere will rotate into a geoeffective position on August 21. Another coronal hole, in the northern hemisphere, is probably too far to the north to be geoeffective when in rotates across the central meridian on August 20-21. Forecast The geomagnetic field is expected to be quiet to unsettled on August 18-20. 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 9123 20000808 3 N21W45 0010 BXO 9124 20000810 18 S12W24 0030 CSO 9125 20000810 35 N26W22 0200 EAI beta-gamma 9127 20000811 7 S36W56 0160 DAO 9128 20000812 10 N12W06 0010 BXO 9129 20000812 9 S06E09 0150 CSO 9130 20000813 S23W65 plage 9131 20000813 5 N14E21 0090 CSO 9132 20000814 5 N21E14 0010 BXO 9133 20000814 3 S08W40 0000 AXX 9134 20000814 5 N06E29 0000 AXX 9135 20000815 23 S12W13 0120 DAO 9136 20000817 9 N07W06 0120 DAO Total number of sunspots: 132 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.07 165.6 113.5 94.3 (+1.2) 1999.08 170.7 93.7 97.5 (+3.2) 1999.09 135.7 71.5 102.3 (+4.8) 1999.10 164.8 116.7 107.8 (+5.5) 1999.11 191.5 133.2 110.9 (+3.1) 1999.12 169.8 84.6 111.0 (+0.1) 2000.01 158.1 90.1 112.8 (+1.8) 2000.02 174.1 112.9 (117.0 predicted, +4.2) 2000.03 208.2 138.5 (120.7 predicted, +3.7) 2000.04 184.2 125.3 (122.9 predicted, +2.2) 2000.05 184.9 120.8 (123.7 predicted, +0.8) 2000.06 179.8 124.9 (125.3 predicted, +1.6) 2000.07 202.3 169.1 2000.08 173.0 (1) 100.4 (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]