Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update November 28, 1999 at 04:00 UTC. Minor update posted at 06:32 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update November 2, 1999)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update November 2, 1999)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update November 2, 1999)] [Historical solar and geomagnetic data charts 1954-1999] [Experimental solar data chart January 1998-September 1999] Recent development The geomagnetic field was quiet on November 26. Solar wind speed ranged between 369 and 479 km/sec. Solar flare activity was high. Solar flux was 169.0, the planetary A index was 3 (3-hour Kp indices: 0011 1211, Boulder K indices: 0010 1211). Region 8771 was mostly unchanged and continued its high frequency flare activity. Further major flares are possible as the region rotates over the west limb today and early tomorrow. Region 8772 was quiet and stable. Region 8773 has become more unstable and could produce occasional C flares. Region 8774 was quiet and stable, the region appears to be spotless early on Nov. 28. Region 8776 was quiet and stable. Region 8778 developed slowly and is capable of minor M class flaring. Region 8779 was quiet and stable. Region 8780 reemerged with a single spot, however, the region appears to have become spotless again. Region 8781 developed slowly and could soon become capable of minor M class flaring. New region 8782 emerged in the northeast quadrant near the central meridian. Comment added at 07:32 UTC on November 28: Region 8771 has produced 2 M flares today, the first an M3.5 event at 01:46 UTC, the second an M1.2 event at 05:57 UTC. The region is very hot and could easily produce a major flare today. The interplanetary magnetic field has swung moderately strongly southwards over the last couple of hours. This could cause the geomagnetic field to become unsettled to active. Flares and CMEs 10 C flares, 2 M flares and 1 X flare were recorded on November 27. Region 8771 produced 4 C flares, 2 M flares (an M2.8/1N event at 03:01 UTC and an M1.2/1N event at 05:48 UTC) and 1 X flare (an X1.4/2B major flare at 12:12 UTC). None of the events appear to have been associated with significant CMEs. Region 8778 was the source of 2 C flares, a C5.6/1N event at 04:57 UTC and a long duration C9.9/1N event peaking at 05:08 UTC. The latter event may have been associated with a CME, however, as online LASCO images have been unavailable since the evening of Nov.26, this possibility is uncertain. November 26: Region 8778 was the source of 3 C flares, one of which was interesting. A C3.9 flare at 07:05 UTC was accompanied by a moderately strong type II sweep. A coronal mass ejection and a Moreton wave was observed in association with the flare. As this event occurred while the region was near the central meridian, there is a high probability of a CME impact at Earth sometime between late on November 28 and noon on November 29. The background x-ray flux is at the class B9 level. Coronal holes A well defined coronal hole in the northern hemisphere was at the central meridian on November 27, however, it may be located too far to the north to be geoeffective. A coronal hole in the southern hemisphere will rotate into a geoeffective position December 2-4. Forecast The geomagnetic field is expected to be quiet to unsettled on November 28. On November 29 a CME could impact Earth and cause active to major storm conditions. On November 30 a coronal stream could reach Earth and cause unsettled to active conditions. Low frequency (below 2 MHz) radio wave propagation along east-west paths over high and upper middle latitudes is generally 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 Location region numbered no. at Area Classification Comment sunspots midnight 8769 991115 S12W81 plage 8771 991117 15 S14W78 0720 EKI beta-gamma-delta 8772 991118 6 N10W45 0010 BXO 8773 991119 4 S12W60 0020 BXO 8774 991119 1 N20W34 0000 AXX 8776 991120 4 S27W72 0080 DSO 8777 991121 S27W38 plage 8778 991121 36 S14W19 0180 EAI beta-gamma 8779 991124 3 S11W70 0040 DRO 8780 991124 1 S16E14 0000 AXX 8781 991124 13 S13E34 0100 DSO 8782 991127 4 N11E01 0010 BXO Total number of sunspots: 87 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 9809 138.3 92.9 69.5 (+1.7) 9810 117.2 55.5 70.5 (+1.0) 9811 140.1 74.0 73.0 (+2.5) 9812 150.1 81.9 77.9 (+4.9) 9901 140.6 62.0 82.6 (+4.7) 9902 141.9 66.3 84.6 (+2.0) 9903 126.3 68.8 83.8 (-0.8) 9904 117.2 63.7 85.4 (+1.6) 9905 148.4 106.4 (90.4 predicted, +5.0) 9906 169.8 137.7 (94.6 predicted, +4.2) 9907 165.6 113.5 (99.6 predicted, +5.0) 9908 170.7 93.7 9909 135.7 70.6 9910 164.8 116.4 9911 194.3 (1) 185.9 (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]