Solar Terrestrial Activity Report [Image] Last update May 17, 2000 at 02:00 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 unsettled to active on May 16. Solar wind speed ranged between 390 and 565 km/sec. A disturbance appears to have arrived at ACE between 22h and 23:30 UTC, there was a significant increase in solar wind speed from 430 to 570 km/sec as well as an increased southward swing of the interplanetary magnetic field. The source of the disturbance could be a filament eruption observed late on May 13 and early on May 14. Solar flare activity was moderate. Solar flux was 258.7 (new high for solar cycle 23), the planetary A index was 18 (3-hour K indices: 3434 3333, Boulder K indices: 2334 3323). Region 8989 was quiet and stable, the region is rotating over the west limb. Region 8990 was mostly quiet and stable. Region 8991 was quiet and stable. Region 8992 decayed into spotless plage. Region 8993 could produce a minor M flare while rotating off the visible disk today. Region 8994 will be rotating over the west limb today. Region 8996 was mostly quiet and unchanged and still has X class flare potential. Region 8997 was quiet and stable. Region 8998 developed further and could produce a major flare. Region 8999 was quiet and stable. Region 9000 decayed into spotless plage. Region 9001 reemerged with a few spots. Region 9002 is a large and complex region. Further M class flares are likely and an X class flare would not be a surprise. Region 9003 decayed slowly and was quiet. Region 9004 developed slowly and was quiet. New region 9005 emerged in the southwest quadrant. A new region is emerging near the southeast limb and could produce C flares. Flares and CMEs A total of 10 C flares and 1 M flare were observed on May 16. Region 8998 produced a C2.6 flare at 01:07, a C3.1 flare at 01:50 and a C2.6 flare at 04:12 UTC. Region 8993 generated a C4.5 flare at 03:33 and a C2.4 flare at 04:54 UTC. Region 8994 was the source of a C4.0 flare at 07:22 UTC. Region 8989 produced a C4.0 flare 12:39 UTC. Region 9002 generated a C7.4 flare at 08:43 and an M3.2 flare at 15:51 UTC. A filament eruption starting to the north of region 8996 was observed starting at 19:48 UTC in LASCO EIT images. The eruption may have caused a potentially geoeffective CME which could arrive on May 19. May 15: Region 9002 produced a long duration M4.4 event peaking at 09:02 UTC. This event was accompanied by a large full halo CME off the northeast limb. Earth will likely receive an impact on May 18. The background x-ray flux is at the class C3 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be unsettled to minor storm on May 17-18. 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 Location region numbered no. at Area Classification Comment sunspots midnight 8989 20000507 12 N18W80 0180 DAI 8990 20000507 12 N15W61 0200 CSO 8991 20000508 4 N16W35 0010 BXO 8992 20000509 N09W18 plage 8993 20000508 6 S21W84 0230 EKO 8994 20000510 2 N10W83 0030 BXO 8995 20000511 S19W65 plage 8996 20000511 41 S20E18 1240 EKC beta-gamma 8997 20000511 3 S15W03 0010 BXO 8998 20000512 42 S13E28 0570 FKC beta-gamma 8999 20000513 5 N20E29 0020 BXO 9000 20000513 N10W28 plage 9001 20000513 3 N16W44 0010 CSO 9002 20000514 13 N18E57 0860 EHI beta-gamma-delta 9003 20000514 5 S17W52 0030 CRO 9004 20000515 9 N11E48 0060 CAO 9005 20000516 1 S20W29 0000 AXX Total number of sunspots: 158 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 2000.05 162.9 (1) 90.7 (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]