Solar Terrestrial Activity Report [Image] Last update April 3, 2000 at 04:05 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update April 2, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update April 2, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update April 2, 2000)] [Historical solar and geomagnetic data charts 1954-1999] Recent development The geomagnetic field was unsettled to active on April 2. Solar wind speed ranged between 399 and 501 km/sec. Solar flare activity was low. Solar flux was 219.3, the planetary A index was 16 (3-hour K indices: 4343 3333, Boulder K indices: 4333 3322). Region 8924 was mostly unchanged and quiet, the region will rotate off the visible disk on April 5. Region 8925 decayed further and could generate occasional C flares. Region 8928 was quiet and stable. Region 8929 once again decayed into spotless plage. Regions 8931, 8932 and 8933 developed slowly and may be capable of minor M class flaring. Region 8935 was quiet and appears to be slowly decaying. Region 8936 developed slowly and has M class flare potential. Region 8938 was quiet and stable. Region 8939 did not change significantly and will likely produce occasional C flares and perhaps a minor M flare. Region 8940 was quiet and stable. Region 8942 developed slowly and could produce C flares. Region 8943 developed further and could generate occasional C flares. Region 8944 was quiet and stable. Region 8945 developed slowly and was mostly quiet. Flares and CMEs A total of 3 C flares were recorded on April 2. Region 8936 produced a long duration C6.1 event peaking at 17:47 UTC, a CME may have accompanied the LDE. Region 8939 generated a C2.4 flare at 08:42 UTC while region 8925 managed a C5.2 flare at 19:17 UTC. March 31: An interesting filament eruption occurred near region 8934 over the central meridian starting just after 10h UTC. This event may have produced a geoeffective CME. 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 active on April 2-3. On April 3 or early on April 4 a CME could impact Earth and cause unsettled to minor storm conditions. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is 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 8924 20000323 11 N11W69 0330 DAO beta-gamma 8925 20000323 4 S18W56 0040 DAO 8928 20000324 1 N21W64 0020 HSX 8929 20000325 S22W51 plage 8930 20000325 S36W50 plage 8931 20000326 17 S14W46 0140 DAO 8932 20000326 11 S12W19 0100 CSO 8933 20000327 17 N17W44 0110 DSO 8934 20000327 N21W28 plage 8935 20000329 13 S07W20 0120 DAO 8936 20000329 36 S15E21 0360 DAI beta-gamma-delta 8937 20000329 N26E12 plage 8938 20000330 3 S04E17 0020 AXX 8939 20000330 9 N23E29 0120 DAO 8940 20000330 1 N14E25 0020 HSX 8941 20000330 N25E15 plage 8942 20000331 10 S12W08 0050 CRO 8943 20000331 11 N23W06 0080 DSO 8944 20000401 1 N09E58 0090 HSX 8945 20000401 6 S17E59 0100 DSO Total number of sunspots: 151 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 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 71.5 102.3 (+4.8) 1999.10 164.8 116.4 (108.6 predicted, +6.3) 1999.11 191.5 132.7 (112.3 predicted, +3.7) 1999.12 169.8 86.4 (111.9 predicted, -0.4) 2000.01 158.1 90.2 (112.7 predicted, +0.8) 2000.02 174.1 112.3 (116.2 predicted, +3.5) 2000.03 208.2 138.2 2000.04 221.1 (1) 19.6 (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]