Solar Terrestrial Activity Report [Image] Last update October 25, 2000 at 01:20 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update October 2, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update October 2, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update October 2, 2000)] [Historical solar and geomagnetic data charts 1954-2000 (last update October 20, 2000)] Recent development The geomagnetic field was quiet to active on October 24. Solar wind speed ranged between 383 and 470 km/sec. Solar flare activity was low. Solar flux was 159.2, the planetary A index was 11 (3-hour K indices: 2234 3222, Boulder K indices: 2233 4312). Region 9198 decayed slowly and was quiet. Region 9199 was quiet and stable. Region 9200 decayed into spotless plage, as did region 9202. Region 9201 decayed slowly and could produce C flares. Region 9206 was quiet and stable. Region 9207 developed slowly and could produce C class flares. Region 9208 was quiet and stable. A large sunspot region is at and just behind the southeast limb, this region could produce M class flares. Flares and CMEs A total of 2 C class events were recorded on October 24. An interesting very long duration event peaking at 09:32 UTC may have had its origin in or near region 9207 near the southeast limb. A very wide full halo CME was observed in LASCO C3 images following this event. If the source was region 9207 the CME could impact Earth on October 27 and cause unsettled to minor storm conditions. It should be observed that a similar very wide CME and long duration event was observed on October 21 when region 9207 was at the southeast limb. The background x-ray flux is at the class B5 level. Coronal holes A small well placed coronal hole in the southern hemisphere will rotate into a geoeffective position on October 26. Forecast The geomagnetic field is expected to be quiet to unsettled on October 25-26. Quiet to minor storm is possible on October 27. A coronal stream could cause unsettled to active conditions on October 29. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair to 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 9197 20001012 N25W88 plage 9198 20001014 5 S30W61 0110 CAO 9199 20001015 4 N07W63 0090 DSO 9200 20001016 S13W45 plage 9201 20001017 23 N18W23 0200 EAI 9202 20001018 N13W50 plage 9203 20001020 N13W69 plage 9204 20001020 N10W38 plage 9205 20001021 N36W59 plage 9206 20001023 1 N21E40 0020 HSX 9207 20001023 5 S18E51 0030 CAO 9208 20001023 1 S09E63 0020 HSX Total number of sunspots: 39 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.09 135.7 71.5 102.3 (+4.8) 1999.10 164.8 116.7 107.8 (+5.5) 1999.11 191.5 133.2 110.9 (+3.1) 1999.12 169.8 84.6 111.0 (+0.1) 2000.01 158.1 90.1 112.8 (+1.8) 2000.02 174.1 112.9 116.6 (+3.8) 2000.03 208.2 138.5 119.8 (+3.2) 2000.04 184.2 125.3 (121.0 predicted, +1.2) 2000.05 184.9 120.8 (121.3 predicted, +0.3) 2000.06 179.8 124.9 (122.8 predicted, +1.5) 2000.07 202.3 169.1 (124.9 predicted, +2.1) 2000.08 163.0 130.5 (125.0 predicted, +0.1) 2000.09 182.1 109.9 2000.10 163.4 (1) 108.4 (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]