Solar Terrestrial Activity Report [Image] Last update March 27, 2000 at 02:35 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update March 2, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update March 2, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update March 2, 2000)] [Historical solar and geomagnetic data charts 1954-1999] Recent development The geomagnetic field was quiet to unsettled on March 26. Solar wind speed ranged between 446 and 586 km/sec, gradually decreasing. Solar flare activity was moderate. Solar flux was 211.3, the planetary A index was 5 (3-hour K indices: 1022 2321, Boulder K indices: 1111 1422). Region 8913 is rotating over the west limb. Region 8915 was quiet and stable. Region 8916 decayed slowly and was quiet. Region 8917 will rotate off the visible disk early today. Region 8921 was mostly unchanged and has minor M class flare potential. Region 8923 decayed slowly and could become spotless today. 8924 developed and shold be capable of minor M class flaring. Region 8925 developed at a moderate pace and could soon become capable of producing an M flare. Region 8926 maintained its magnetic delta configuration could produce another minor M flare. Region 8927 developed and may become capable of M class flaring today. Region 8928 did not change significantly and is likely to produce C flares. Regions 8929 and 8930 decayed into spotless plage. New region 8931 emerged in the southeast quadrant while new region 8932 rotated partly into view at the southeast limb. Region 8932 )or another region just behind it) could be capable of M class flaring. Flares and CMEs A total of 4 C flares and 1 M flare were recorded on March 26. Region 8916 produced a C2.8 flare at 15:07 UTC. Region 8926 generated an M2.3 flare at 17:34 UTC and a C4.1 flare at 22:12 UTC. March 25: Region 8921 generated the most interesting flare of the day, a C7.4/1F event at 22:43 UTC. This event was accompanied by moderately strong type II (with an estimated exit speed of 1700 km/sec) and IV sweeps and occurred almost on top of the central meridian. The associated coronal mass ejection has a fairly high chance of impacting Earth. With LASCO movies unavailable it is difficult to state when the CME will arrive and how severe the impact will be. The most likely time of arrival is sometime between late on March 27 and early on March 29. This will likely result in unsettled to minor or major storming. The background x-ray flux is at the class C1 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to unsettled on March 27. A CME could impact Earth sometime from late on March 27 until early on the 29th and cause unsettled to major storming. 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 Location region numbered no. at Area Classification Comment sunspots midnight 8913 20000314 1 S16W84 0040 HSX 8915 20000316 1 N23W52 0150 HSX 8916 20000317 5 N13W42 0140 DSO 8917 20000318 1 N18W85 0070 HSX 8919 20000319 S21W35 plage 8920 20000320 N24W23 plage 8921 20000320 29 S17W03 0260 DAI 8922 20000321 N12W09 plage 8923 20000322 1 S26W12 0000 AXX 8924 20000323 24 N10E27 0200 DAI beta-gamma 8925 20000323 17 S18E35 0170 DSI beta-gamma 8926 20000323 12 S09W58 0090 DSO beta-gamma-delta 8927 20000323 17 N17W41 0130 DSO beta-gamma 8928 20000324 8 N19E33 0060 CSO 8929 20000325 S25E40 plage 8930 20000325 S36E41 plage 8931 20000326 8 S14E47 0010 BXO 8932 20000326 1 S14E71 0070 HSX Total number of sunspots: 125 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.02 141.9 66.1 84.6 (+2.0) 1999.03 126.3 69.1 83.8 (-0.8) 1999.04 117.2 63.9 85.4 (+1.6) 1999.05 148.4 106.3 90.4 (+5.0) 1999.06 169.8 137.7 93.0 (+2.6) 1999.07 165.6 113.5 94.4 (+1.4) 1999.08 170.7 93.7 97.5 (+3.1) 1999.09 135.7 71.5 (102.6 predicted, +5.1) 1999.10 164.8 116.4 (107.7 predicted, +5.1) 1999.11 191.5 132.7 (110.2 predicted, +2.5) 1999.12 169.8 86.4 2000.01 158.1 90.2 2000.02 174.1 112.3 2000.03 208.0 (1) 164.9 (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]