Solar Terrestrial Activity Report [Image] Last update May 27, 2000 at 06:00 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 minor storm on May 26. Solar wind speed ranged between 377 and 491 km/sec. Solar flare activity was low. Solar flux was 167.9, the planetary A index was 23 (3-hour K indices: 3455 3332, Boulder K indices: 3455 2322). Region 9002 could produce C flares while rotating over the west limb today. Region 9004 rotated over the west limb early today. Region 9009 was quiet and stable. Region 9010 was quiet and stable, as was region 9011. Region 9016 was quiet and stable and could become spotless today. Region 9017 has M class flaring potential. New region 9018 emerged in the southwest quadrant near the central meridian. New region 9019 emerged in the southwest quadrant. Flares and CMEs A total of 8 C flares were observed on May 26. Region 9002 produced a C3.4/1F flare at 01:32, a C2.2 flare at 08:08 and a C3.3 flare at 15:30 UTC. Region 9017 generated a C1.0 flare at 04:02 UTC. Region 9004 was the source of a C2.9 flare at 18:07 UTC. An optically uncorrelated C6.1 flare was observed at 11:35 UTC. The background x-ray flux is at the class B5 level. Coronal holes A moderately large coronal hole in the northern hemisphere extending into the southern hemisphere will rotate into a geoeffective position on May 26-28. Forecast The geomagnetic field is expected to be quiet to unsettled on May 27. A coronal stream could arrive on May 29 or 30 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 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 9002 20000514 5 N20W79 0360 EAO 9004 20000515 4 N14W87 0110 DSO 9008 20000517 S30W66 plage 9009 20000518 1 S13W36 0000 AXX 9010 20000518 19 N23W36 0050 CSO 9011 20000519 8 N21W26 0140 CAO 9014 20000520 S43W57 plage 9015 20000524 N13W34 plage 9016 20000524 1 N26E21 0000 AXX 9017 20000524 10 S14E55 0610 EKO 9018 20000526 10 S20W11 0020 BXO 9019 20000526 7 S34W38 0020 BXO Total number of sunspots: 65 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 2000.05 190.9 (1) 163.4 (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]