Solar Terrestrial Activity Report [Image] Last update June 21, 2000 at 03:20 UTC. Minor update posted at 09:42 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update June 2, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update June 2, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update June 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 June 20. Solar wind speed ranged between 343 and 422 km/sec. Solar flare activity was low. Solar flux was 183.7, the planetary A index was 9 (3-hour K indices: 2223 3332, Boulder K indices: 2222 3322). Region 9036 was quiet and stable and will rotate off the visible disk today. Region 9040 was quiet and stable. Region 9042 was mostly unchanged and will likely produce further C flares. Minor M flares are possible as well. Region 9046 seems to be in slow decay. Further C class flares are likely and the region could produce an M flare. Region 9048 decayed slowly and was quiet. Regions 9049, 9050 and 9051 were quiet and stable. Region 9052 is developing slowly and could produce C flares. Region 9053 was quiet and stable. New region 9054 rotated into view at the northeast limb. Comment added at 09:42 on June 21: What appears to have been a fairly large filament eruption started well to the east of region 9046 at 0840 UTC. If this event produced an interesting CME an additional update will be posted later today. At 09:29 an M1.3 flare was observed, its origin was in region 9042. Flares and CMEs A total of 6 C flares were observed on June 20. Region 9042 produced a C4.3 flare at 06:51 and a C6.2 flare at 19:28 UTC. The latter event was accompanied by a moderately strong type II sweep. Region 9046 generated a C1.6 flare at 19:51 UTC. A couple of partial halo CMEs were observed during the day. Without LASCO-EIT images it is uncertain if any of the CMEs had their origin on the visible disk. However, there were no flares or obvious filament eruptions just before the CMEs became visible, and it's likely that the sources were backside events. The background x-ray flux is at the class B7 level. Coronal holes A well defined coronal hole in the southern hemisphere will likely rotate into a geoeffective position on June 24. Forecast The geomagnetic field is expected to be quiet to unsettled on June 21-22. 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 9036 20000608 1 S17W83 0180 HSX 9037 20000610 N22W78 plage 9040 20000611 5 N20W44 0050 DSO 9042 20000612 46 N24W24 0420 FKO beta-gamma 9045 20000614 S17W59 plage 9046 20000614 26 N21E06 0540 DHI beta-gamma 9047 20000615 S27W30 plage 9048 20000616 4 N09W69 0050 DSO 9049 20000616 2 S36E09 0020 HSX 9050 20000617 9 S11W35 0040 DSO 9051 20000617 1 N17E24 0000 AXX 9052 20000618 12 S26W39 0100 DAO 9053 20000619 1 N04E34 0010 HRX 9054 20000620 2 N09E64 0030 CSO Total number of sunspots: 109 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 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) 1999.11 191.5 133.2 110.9 (+3.2) 1999.12 169.8 84.6 (111.2 predicted, +0.3) 2000.01 158.1 90.2 (112.4 predicted, +1.2) 2000.02 174.1 112.3 (115.8 predicted, +3.4) 2000.03 208.2 138.2 (119.6 predicted, +3.8) 2000.04 184.2 125.3 (121.7 predicted, +2.1) 2000.05 184.9 120.8 2000.06 182.7 (1) 127.5 (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]