Solar Terrestrial Activity Report [Image] Last update May 28, 2000 at 04:30 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 unsettled on May 27. Solar wind speed ranged between 358 and 418 km/sec. Solar flare activity was low. Solar flux was 161.8, the planetary A index was 12 (3-hour K indices: 3322 3333, Boulder K indices: 3222 2313). Region 9002 was quiet and stable and rotated over the west limb early today. Region 9009 was quiet and stable, as were regions 9010, 9011 and 9016. Region 9017 added several spots but lost some of its area. The region could produce isolated M class flares. Region 9018 developed slowly and could produce C flares. Region 9019 developed slowly and is quite warm. C class flares are possible. New region 9020 emerged in the northeast quadrant near equator and the central meridian. An active region is at the southeast limb. An active region just behind the northeast limb produced a CME late in day. Flares and CMEs A total of 3 C flares were observed on May 27, none of the flares were optically correlated. 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 will rotate into a geoeffective position on May 26-28. Forecast The geomagnetic field is expected to be quiet to unsettled on May 28. 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 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 3 N20W88 0170 DSO 9008 20000517 S30W79 plage 9009 20000518 1 S16W55 0000 AXX 9010 20000518 12 N24W49 0070 CSO 9011 20000519 9 N21W39 0140 DSO 9014 20000520 S43W70 plage 9015 20000524 N13W47 plage 9016 20000524 1 N26E06 0000 AXX 9017 20000524 20 S13E42 0520 EKO 9018 20000526 11 S21W24 0080 DSO 9019 20000526 11 S34W46 0050 DSO 9020 20000527 3 N03E06 0010 BXO Total number of sunspots: 71 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 2000.05 189.8 (1) 168.5 (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]