Solar Terrestrial Activity Report [Image] Last update December 19, 2000 at 04:10 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update December 2, 2000) - Has cycle 23 peaked?] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update December 2, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update December 2, 2000)] [Historical solar and geomagnetic data charts 1954-2000 (last update October 20, 2000)] Recent development The geomagnetic field was quiet to unsettled on December 18. Solar wind speed ranged between 353 and 397 km/sec under the influence of a weak coronal stream. Solar flare activity was low. Solar flux was 198.0, the planetary A index was 10 (3-hour K indices: 2333 2323, Boulder K indices: 1233 1312). Region 9262 decayed again and could become spotless today. Region 9264 decayed slowly and was quiet. Region 9265 was quiet and stable. Regions 9267 and 9268 decayed slowly and were quiet. Region 9269 decayed significantly and is not likely to produce other than occasional C class flares. Regions 9271 and 9272 decayed into spotless plage. Region 9273 was quiet and stable, as was region 9275. Region 9276 is at the southwest limb and will likely continue to produce C flares while it rotates over the limb, a minor M class flare is possible. Region 9277 was mostly quiet and stable, the region will rotate out of view today. Region 9278 developed slowly and may be capable of producing a minor M class flare. New region 9279 rotated into view at the southeast limb. An active region is currently rotating into view at a low latitude at the northeast limb, the region could be capable of M class flaring. Flares and CMEs A total of 16 C class events were recorded on December 18. Region 9277 produced a C3.2 flare at 01:24 and a C2.9 flare at 18:10 UTC. Region 9278 generated a C5.7 flare at 02:46 and a C2.4 flare at 22:10 UTC. Region 9276 was the source of a C5.2 flare at 08:59, a C3.2 flare at 13:31 and a C3.5 flare at 23:12 UTC. Region 9269 produced a C7.0 flare at 11:11 UTC. The flare was accompanied by a moderate type II sweep and a visually weak and slow full halo coronal mass ejection. With the CME occurring near the center of the solar disk Earth will receive an impact, most likely on December 21. The background x-ray flux is at the class C1-C2 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to unsettled on December 19-20. A CME will cause unsettled to minor storm conditions on December 21 and maybe even on December 22. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair. 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 9262 2000.12.08 2 N16W58 0010 BXO 9263 2000.12.09 N18W53 plage 9264 2000.12.10 15 S25W36 0140 EAO 9265 2000.12.10 1 N19W34 0010 HRX 9267 2000.12.11 8 N08W57 0130 DAO 9268 2000.12.13 1 S18E09 0080 HSX 9269 2000.12.13 5 N14W06 0040 CSO 9270 2000.12.13 S10W55 plage 9271 2000.12.14 S20W80 plage 9272 2000.12.14 N12W34 plage 9273 2000.12.15 4 N20E31 0010 BXO 9274 2000.12.16 N16W45 plage 9275 2000.12.16 2 N22W56 0010 AXX 9276 2000.12.17 5 S12W85 0100 DAO beta-gamma 9277 2000.12.17 1 N16W76 0010 AXX 9278 2000.12.17 8 N09E51 0090 DAO beta-gamma 9279 2000.12.18 2 S11E62 0060 HAX Total number of sunspots: 54 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.11 191.5 133.2 111.0 (+3.2) 1999.12 169.8 84.6 111.1 (+0.1) 2000.01 158.1 90.1 112.9 (+1.8) 2000.02 174.1 112.9 116.7 (+3.8) 2000.03 208.2 138.5 119.9 (+3.2) 120.8 (+0.9) 2000.04 184.2 125.5 cycle 23 peak candidate 2000.05 184.9 121.6 119.0 (-1.8) 2000.06 179.8 124.9 (118.3 predicted, -0.7) 2000.07 202.3 169.1 (119.8 predicted, +1.5) 2000.08 163.0 130.5 (120.5 predicted, +0.7) 2000.09 182.1 109.9 (119.6 predicted, -0.9) 2000.10 167.4 100.1 (118.4 predicted, -1.2) 2000.11 178.8 106.5 (116.4 predicted, -2.0) 2000.12 162.8 (1) 78.8 (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 noted in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]