Solar Terrestrial Activity Report [Image] Last update June 18, 2000 at 01:50 UTC. Minor update posted at 03:10 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 17. Solar wind speed ranged between 429 and 497 km/sec. Solar flare activity was moderate. Solar flux was 193.1, the planetary A index was 10 (3-hour K indices: 3122 3333, Boulder K indices: 2022 1223). Region 9033 was mostly unchanged and may be capable of further minor M class flare production while at or just behind the west limb today and tomorrow. Region 9034 was quiet and stable and will rotate off the visible disk today. Region 9035 rotated over the west limb. Region 9036 decayed significantly and was quiet. Region 9037 decayed quickly, losing all but one spot, and was quiet. Region 9040 decayed slowly and was quiet. Region 9041 decayed further and will rotate out of view early today. Region 9042 lost some of its areal coverage but was otherwise mostly unchanged and quiet. Occasional M class flares are possible. Region 9045 decayed into spotless plage. Region 9046 was generally quiet and lost a few of its spots. Region 9048 developed slowly and could produce further C flares. Region 9049 was quiet and stable. New region 9050 emerged in the southeast quadrant near the central meridian. New region 9051 rotated into view at the northeast limb. Comment added at 03:10 UTC on June 18: Region 9033 produced an impulsive X1.0 flare at 01:58 UTC. The flare covered only a small area of the disk. There is a chance the region could produce another major flare within 24-36 hours, perhaps even a large proton flare. Flares and CMEs A total of 5 C flares and 1 M flare were observed on June 17. Region 9033 produced an M3.5/2B flare at 02:37 UTC. A large coronal mass ejection was observed off the west limb in association with the flare, no terrestrial impact appears likely judging by LASCO C3 images. A minor proton flux enhancement has been in progress since a few hours after the flare. Region 9033 was the source of a C2.6 flare at 13:59 UTC as well. Region 9042 generated a C2.2 flare at 12:24 UTC while region 9048 managed a C2.5 flare at 18:08 UTC. June 15: Region 9041 was the source of an M1.8/2N long duration event peaking at 19:57 UTC. A weak type II sweep was detected in association with the LDE. A fairly wide partial halo coronal mass ejection was observed mainly off the west limb and the north pole. There is a chance Earth could receive a minor impact from the CME on June 18 or 19. The background x-ray flux is at the class C1 level. Coronal holes No obvious coronal holes are approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to unsettled on June 18. Late on June 18 or sometime during June 19 a weak CME impact is possible and could 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 9033 20000605 5 N24W79 0070 CSO 9034 20000606 1 S10W81 0080 HRX 9036 20000608 6 S19W43 0170 CSO 9037 20000610 1 N21W40 0010 HRX 9040 20000611 3 N19W05 0060 CAO 9041 20000611 3 N19W87 0030 DRO 9042 20000612 36 N22E16 0550 FKI beta-gamma 9043 20000613 N25W51 plage 9044 20000613 S24W79 plage 9045 20000614 S14W20 plage 9046 20000614 11 N19E44 0540 DKO beta-gamma 9047 20000615 S32E04 plage 9048 20000616 4 N07W27 0020 DAO 9049 20000616 4 S38E52 0040 CRO 9050 20000617 3 S13E06 0010 CRO 9051 20000617 1 N16E61 0010 HRX Total number of sunspots: 78 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 2000.06 182.6 (1) 105.4 (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]