Solar Terrestrial Activity Report [Image] Last update June 1, 2000 at 04:40 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 31. Solar wind speed ranged between 508 and 650 km/sec, slowly decreasing all day. Solar flare activity was low. Solar flux was 154.4, the planetary A index was 12 (3-hour K indices: 3422 2323, Boulder K indices: 3522 1213). Region 9011 was quiet and stable and has rotated over the west limb. Region 9017 was mostly unchanged and still has M class flaring potential. Region 9018 decayed slowly and was quiet, the region is rotating off the visible disk. Regions 9020 and 9021 decayed into spotless plage. Regions 9022 and 9023 were quiet and stable. Region 9024 decayed into spotless plage. New region 9025 emerged near the northwest limb. An active and interesting region at the northeast limb is rotating onto the disk. The region appears to be large and could be capable of M class flaring. Flares and CMEs A total of 4 C flares were observed on May 31. A C3.9 flare at 01:44 appeared to have its origin at or just behind the southwest limb. The region at the northeast limb produced a C4.8 flare at 13:59 and a long duration C3.9 event peaking at 18:25 UTC. A filament eruption was observed over the central meridian in the northern hemisphere starting at 06:48 UTC. A nearly full halo coronal mass ejection was observed in LASCO C2 images from 08:06 UTC, the only part of the disk where material motion was not detected was over the central west limb. A terrestrial impact is likely on June 3. The background x-ray flux is at the class B6 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to active on June 1 due to a coronal stream and quiet to unsettled on June 2. A CME impact is likely on June 3 and could result in unsettled to major 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 no. Location at region numbered sunspots midnight Area Classification Comment 9011 20000519 2 N20W90 0060 DSO 9016 20000524 N26W44 plage 9017 20000524 27 S13W10 0680 FKO beta-gamma 9018 20000526 3 S20W82 0020 CRO 9020 20000527 N04W48 plage 9021 20000528 N04W23 plage 9022 20000528 8 S22E25 0030 CSO 9023 20000529 8 S02W39 0030 CSO 9024 20000529 S15E29 plage 9025 20000531 2 N15W64 0000 AXX Total number of sunspots: 50 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 2000.05 184.9 (1) 188.8 (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]