Solar Terrestrial Activity Report [Image] Last update May 12, 2000 at 04:25 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 11. Solar wind speed ranged between 279 and 332 km/sec. A disturbance arrived at ACE at approximately 01:20 UTC on May 12 and may be related to the arrival of the CME from the filament eruption on May 8. Solar flare activity was low. Solar flux was 177.7, the planetary A index was 6 (3-hour K indices: 2231 2222, Boulder K indices: 1230 2112). Region 8982 was quiet and will rotate over the west limb today. Regions 8983 and 8987 were quiet and stable, both could become spotless today. Region 8989 developed slowly and could produce C flares and minor M flares. Region 8990 developed further and could generate C and M class flares. Region 8991 was mostly unchanged and quiet. Region 8992 was quiet and stable. Region 8993 developed slowly and could produce minor M class flares. Region 8994 was quiet and stable. New region 8995 emerged in the southeast quadrant near the central meridian. New region 8996 rotated partly into view at the southeast limb and has M class flare potential. New region 8997 rotated into view at the southeast limb. Flares and CMEs A total of 7 C flares were observed on May 11. Region 8993 produced a C3.3 flare at 05:55 UTC. All other flares were optically uncorrelated, among them a C4.5 flare at 08:19, a C7.8 flare at 10:11 and a C3.6 flare at 22:24 UTC. A huge CME was observed early on May 12 below the south pole, the source could be old region 8970. May 10: Region 8990 generated the most significant event of the day, a long duration C8.7/2N event peaking at 19:41 UTC. A strong type II sweep and a weak type IV sweep were observed as well. A partial halo CME covering the entire eastern hemisphere was seen in LASCO C2 images. The CME could impact Earth with the most likely impact time being the first half of May 14. The background x-ray flux is at the class C1 level. Coronal holes A small well placed coronal hole in the southern hemisphere was in a geoeffective position on May 8-9. Forecast The geomagnetic field is expected to be unsettled to active on May 12 with possible minor storm intervals. Quiet to active is expected for May 13 while the possible arrival of a CME on May 14 could cause unsettled to minor storm conditions. 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 8982 20000503 3 S24W84 0010 BXO 8983 20000504 1 N25W34 0000 AXX 8984 20000505 S13W67 plage 8985 20000505 N12W27 plage 8987 20000507 2 N10W45 0000 AXX 8988 20000507 N08W56 plage 8989 20000507 14 N16W15 0230 DAI 8990 20000507 25 N14E05 0240 DAI 8991 20000508 10 N16E33 0100 CAO 8992 20000509 2 N11E47 0050 HSX 8993 20000508 22 S24W18 0160 DSI 8994 20000510 7 N09W15 0010 BXO 8995 20000511 3 S19E00 0000 BXO 8996 20000511 3 S18E77 0150 DAO 8997 20000511 1 S14E64 0030 HSX Total number of sunspots: 93 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 (109.8 predicted, +2.1) 1999.12 169.8 84.6 (108.2 predicted, -1.6) 2000.01 158.1 90.2 (108.6 predicted, +0.4) 2000.02 174.1 112.3 (112.0 predicted, +3.4) 2000.03 208.2 138.2 (115.8 predicted, +3.8) 2000.04 184.2 125.3 2000.05 146.7 (1) 47.6 (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]