Solar Terrestrial Activity Report [Image] Last update May 31, 2000 at 04:00 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update May 2, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update May 2, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update May 2, 2000)] [Historical solar and geomagnetic data charts 1954-2000 (last update April 12, 2000)] Recent development The geomagnetic field was quiet to active on May 30. Solar wind speed ranged between 513 and 749 km/sec under the influence of a high speed coronal stream. Solar flare activity was low. Solar flux was 146.4, the planetary A index was 21 (3-hour K indices: 4244 4333, Boulder K indices: 4343 3433). Region 9010 decayed into spotless plage. Region 9011 was quiet and stable and will rotate off the visible disk late today. Region 9016 decayed into spotless plage. Region 9017 was mostly unchanged and still has M class flaring potential. Region 9018 decayed slowly and was quiet. Region 9019 was mostly quiet and stable, the region will rotate off the visible disk today. Regions 9020 and 9021 decayed slowly and were quiet, both regions are spotless early on May 31. Region 9022 was quiet and stable, as were regions 9023 and 9024. An active region at the northeast limb appears to be capable of M class flaring, it should rotate into view over the next couple of days. Flares and CMEs A total of 3 C flares were observed on May 30. The region at the northeast limb produced a C5.0 flare at 20:41 UTC. The background x-ray flux is at the class B6 level. Coronal holes A moderately large coronal hole in the northern hemisphere extending into the southern hemisphere was in a geoeffective position on May 26-29. Forecast The geomagnetic field is expected to be unsettled to active on May 31 and quiet to active on June 1 due to a coronal stream. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor to very 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 9010 20000518 N22W88 plage 9011 20000519 4 N20W77 0100 DSO 9015 20000524 N13W86 plage 9016 20000524 N26W31 plage 9017 20000524 25 S13E02 0650 FKO beta-gamma 9018 20000526 7 S21W65 0060 DSO 9019 20000526 4 S36W86 0050 DAO 9020 20000527 3 N04W35 0010 BXO 9021 20000528 2 N04W10 0000 AXX 9022 20000528 8 S22E40 0040 CSO 9023 20000529 9 S03W25 0010 BXO 9024 20000529 1 S15E42 0000 AXX Total number of sunspots: 63 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.04 117.2 63.9 85.5 (+1.7) 1999.05 148.4 106.3 90.5 (+5.0) 1999.06 169.8 137.7 93.1 (+2.6) 1999.07 165.6 113.5 94.5 (+1.4) 1999.08 170.7 93.7 97.4 (+2.9) 1999.09 135.7 71.5 102.3 (+4.8) 1999.10 164.8 116.7 107.7 (+5.4) 1999.11 191.5 133.2 (110.4 predicted, +2.7) 1999.12 169.8 84.6 (110.2 predicted, -0.2) 2000.01 158.1 90.2 (111.5 predicted, +1.3) 2000.02 174.1 112.3 (114.9 predicted, +3.4) 2000.03 208.2 138.2 (118.7 predicted, +3.8) 2000.04 184.2 125.3 2000.05 185.9 (1) 185.3 (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]