Solar Terrestrial Activity Report [Image] Last update May 13, 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 minor storm on May 12. Solar wind speed ranged between 278 and 393 km/sec. A weak solar wind shock was observed at ACE at 17:08 UTC. The interplanetary magnetic field was moderately southwards until 01h UTC on May 13 and has since been mostly northwards. Solar flare activity was moderate. Solar flux was 190.4, the planetary A index was 22 (3-hour K indices: 3454 3244, Boulder K indices: 1453 2224). Regions 8983 and 8987 were quiet and stable. 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 was mostly unchanged and could produce minor M class flares. Region 8994 was quiet and stable. Region 8995 decayed into spotless plage. Region 8996 rotated fully into view and is a fairly large region capable of producing M flares. Region 8997 was quiet and stable. New region 8998 rotated partly into view at the southeast limb (magnetograms early on May 13 indicate that the region could have a magnetic delta configuration, or possibly that this is actually two very closely located regions). Further M class flares are likely. Another active region is rotating into view at the northeast limb, this region is also capable of M class flaring. Flares and CMEs A total of 8 C flares and 1 M flare were observed on May 12. Most of the flare activity, including several of the optically unassigned flares, was observed near the southeast limb (regions 8996 and 8998). Region 8996 produced a C6.6 flare at 22:44 UTC. Region 8998 generated a long duration C9.8 event peaking at 21:44 and an M1.0 flare at 23:29 UTC. A long duration M1 event was observed early on May 13. A large, fast, very wide and full halo CME was observed near midnight in LASCO C2 images. It's difficult to tell if the CME had its origin in region 8998 or in the region rotating onto the northeast limb. If it was in region 8998 there is a small chance of a terrestrial impact on May 15. 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 C2-C3 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to active on May 13 with a possibility of isolated minor storm intervals. May 14 could see unsettled to minor storm conditions due to a possible CME impact. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor to very 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 8983 20000504 2 N26W48 0000 AXX 8984 20000505 S13W80 plage 8985 20000505 N12W40 plage 8987 20000507 1 N11W62 0000 AXX 8988 20000507 N08W69 plage 8989 20000507 17 N17W28 0340 DKI 8990 20000507 32 N15W08 0300 DAO beta-gamma 8991 20000508 9 N15E20 0060 CAO 8992 20000509 3 N10E34 0040 HSX 8993 20000508 22 S23W31 0160 DSI 8994 20000510 2 N08W30 0000 BXO 8995 20000511 S19W13 plage 8996 20000511 10 S21E67 0520 DKI beta-gamma 8997 20000511 1 S17E50 0020 HSX 8998 20000512 2 S14E73 0060 CSO (beta-gamma-delta) Total number of sunspots: 101 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 2000.05 150.3 (1) 54.5 (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]