Solar Terrestrial Activity Report [Image] Last update May 18, 2000 at 04:55 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 minor storm on May 17. Solar wind speed ranged between 464 and 582 km/sec. Solar flare activity was low. Solar flux was 262.0 (new high for solar cycle 23), the planetary A index was 22 (3-hour K indices: 5552 2233, Boulder K indices: 4553 2223). Region 8989 rotated off the visible disk. Region 8990 was quiet and will rotate over the west limb early on May 19. Region 8991 was quiet and stable. Region 8992 reemerged with a single spot. Region 8993 rotated over the west limb and was quiet. Region 8996 developed quiet and produced several C flares. The region has X class flare potential. Region 8997 was quiet and decayed, the region could become spotless today. Region 8998 could be slowly decaying but is still capable of producing a major flare. Region 8999 was quiet and stable, as was region 9001. Region 9002 is a large and complex region capable of producing a major flare. Region 9003 was quiet and stable. Region 9004 did not change significantly and was quiet. Region 9005 was quiet and stable, the region appears to be spotless early on May 18. New region 9006 emerged at the northwest limb and has already rotated over the limb. New region 9007 emerged in the southeast quadrant at a high latitude. New region 9008 emerged in the southeast quadrant. Flares and CMEs A total of 14 C flares were observed on May 17. Region 8996 produced a C7.7 flare at 00:20, a C3.7 flare at 05:04, a C3.1 flare at 11:16, a C5.5 flare at 13:21, a C3.1 flare at 14:43, a C3.6 flare at 21:30 and a C4.3 flare at 23:53 UTC. Region 9002 generated a C5.4 flare at 03:34, a C4.0 flare at 12:03 and a C4.9 flare at 20:10 UTC. Region 8998 was the source of a C4.1 flare at 04:41 and a C6.1 flare at 09:38 UTC. May 16: A filament eruption 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 with most of the material eject off the northeast limb. Earth will likely receive an impact on May 18. The background x-ray flux is at the class C2 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to minor storm on May 18-19. 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 8989 20000507 4 N18W93 0200 CAO 8990 20000507 5 N17W76 0120 CSO 8991 20000508 2 N16W40 0000 AXX 8992 20000509 1 N09W31 0010 AXX 8993 20000508 3 S23W88 0090 CSO 8995 20000511 S19W78 plage 8996 20000511 53 S21E03 1280 EKC beta-gamma 8997 20000511 2 S17W16 0000 BXO 8998 20000512 40 S13E16 0510 EKC beta-gamma 8999 20000513 5 N20E17 0010 BXO 9000 20000513 N10W41 plage 9001 20000513 1 N17W57 0000 AXX 9002 20000514 29 N18E42 0820 EHI beta-gamma 9003 20000514 6 S17W67 0020 CRO 9004 20000515 14 N11E34 0100 DSO 9005 20000516 1 S18W46 0000 AXX 9006 20000517 3 N26W88 0010 BXO 9007 20000517 2 S42E12 0010 BXO 9008 20000517 1 S31E50 0010 AXX Total number of sunspots: 172 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 2000.05 178.1 (1) 101.7 (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]