Solar Terrestrial Activity Report [Image] Last update May 20, 2000 at 04:30 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 19. Solar wind speed ranged between 458 and 563 km/sec. Solar flare activity was moderate. Solar flux was 254.3, the planetary A index was 9 (3-hour K indices: 2323 3332, Boulder K indices: 3323 3222). Region 8992 decayed into spotless plage. Region 8996 decayed slowly but should still be capable of producing a major flare. Region 8998 decayed slowly, the region will likely continue to produce C flares and has a change of producing isolated M flares. Region 8999 was quiet and stable. Region 9002 did not change significantly and remains capable of producing a major flare. Region 9004 was quiet and stable, however, late on May 19 and early on May 20 the region has developed quickly tripling its areal coverage. Minor M class flares are possible. Regions 9007 and 9008 decayed into spotless plage. Region 9009 was quiet and stable. Region 9010 was mostly quiet and stable but could produce C flares and an isolated minor M flare. New region 9011 was split off from region 9010 at the northeast limb. New region 9012 emerged just to the south of region 8996. Flares and CMEs A total of 7 C flares and 1 M flare were observed on May 19. Region 9002 produced an M1.1 flare at 00:58, a C5.9 flare at 08:30, a C2.9 flare at 11:15 and a C8.5/2F flare at 15:17 UTC. Region 8998 generated a C4 flare at 04:55 and a C3.1 flare at 06:37 UTC. The background x-ray flux is at the class C1-C2 level. Coronal holes A coronal hole in the northern hemisphere may have been too far to the north to be geoeffective when it rotated over the central meridian on May 18. Forecast The geomagnetic field is expected to be quiet to unsettled on May 20-21. 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 8991 20000508 N16W66 plage 8992 20000509 N10W57 plage 8996 20000511 42 S21W22 0950 EKC beta-gamma 8997 20000511 S17W32 plage 8998 20000512 31 S12W09 0490 EAC beta-gamma 8999 20000513 2 N19W09 0000 BXO 9000 20000513 N10W67 plage 9001 20000513 N17W83 plage 9002 20000514 41 N18E18 0730 FKC beta-gamma 9004 20000515 17 N12E06 0130 DAC 9005 20000516 S18W72 plage 9007 20000517 S42W14 plage 9008 20000517 S30E25 plage 9009 20000518 1 S13E55 0040 HSX 9010 20000518 9 N20E58 0180 EHO 9011 20000519 2 N19E69 0240 HSX 9012 20000519 4 S29W24 0000 BXO Total number of sunspots: 149 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.04 117.2 63.9 85.5 (+1.7) 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 (110.4 predicted, +2.7) 1999.12 169.8 84.6 (110.2 predicted, -0.2) 2000.01 158.1 90.2 (111.5 predicted, +1.3) 2000.02 174.1 112.3 (114.9 predicted, +3.4) 2000.03 208.2 138.2 (118.7 predicted, +3.8) 2000.04 184.2 125.3 2000.05 186.1 (1) 119.0 (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]