Solar Terrestrial Activity Report [Image] Last update May 27, 2001 at 03:50 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 1, 2001)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update May 2, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update May 2, 2001)] [Historical solar and geomagnetic data charts 1954-2001 (last update April 8, 2001)] Recent development The geomagnetic field was quiet to unsettled on May 26. Solar wind speed ranged between 426 and 570 km/sec. Solar flare activity was low. Solar flux was 147.4, the planetary A index was 8 (3-hour K indices: 2222 2332, Boulder K indices: 2222 3332). Region 9461 was quiet and stable, as was region 9462. Region 9463 decayed slowly and was quiet. There is still a possibility of an M class flare. Region 9465 was quiet and stable, as were regions 9466 and 9467. Region 9466 is spotless early on May 27. Region 9468 decayed further and was mostly quiet. Region 9472 was quiet and stable. New region 9473 emerged in the northeast quadrant. New region 9474 emerged near the northeast limb. New region 9475 rotated into view at the northeast limb. Flares and CMEs A total of 2 C class events were recorded on May 26. Region 9468 produced C1.1 flares at 12:08 and 16:20 UTC. The background x-ray flux is at the class B3 level. May 25: A filament eruption in the northwest quadrant began at approximately 02:48 UTC as observed in LASCO EIT images. A slow halo CME was observed in LASCO C3 images during the morning and it is likely that the CME is geoeffective. Coronal holes A large southern hemisphere coronal hole will rotate into a geoeffective position on May 28-30. Forecast The geomagnetic field is expected to be quiet to unsettled on May 27. A CME could arrive on May 28 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 fair to 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 9461 2001.05.15 1 N22W71 0030 HSX 9462 2001.05.17 1 N21W40 0070 HSX 9463 2001.05.18 20 N08W38 0530 EKO beta-gamma 9464 2001.05.19 S09W28 plage 9465 2001.05.20 5 S10W18 0020 CRO 9466 2001.05.21 4 S04W25 0050 BXO 9467 2001.05.21 1 S07W13 0070 HSX 9468 2001.05.21 16 N06W02 0150 DAO 9470 2001.05.22 S16W71 plage 9471 2001.05.23 S13W42 plage 9472 2001.05.23 2 N12E21 0020 HAX 9473 2001.05.26 3 N12E12 0010 BXO 9474 2001.05.26 3 N18E53 0030 BXO 9475 2001.05.26 1 N17E71 0050 HSX Total number of sunspots: 57 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 2000.03 208.2 138.5 119.9 (+3.1) 2000.04 184.2 125.5 120.8 (+0.9) cycle 23 sunspot max. 2000.05 184.9 121.6 119.0 (-1.8) 2000.06 179.8 124.9 118.7 (-0.3) 2000.07 202.3 170.1 119.7 (+1.0) 2000.08 163.0 130.5 118.6 (-1.1) 2000.09 182.1 109.7 116.2 (-2.4) 2000.10 167.4 99.4 114.5 (-1.7) 2000.11 178.8 106.8 (112.5 predicted, -2.0) 2000.12 173.6 104.5 (109.9 predicted, -2.6) 2001.01 166.6 95.6 (106.2 predicted, -3.7) 2001.02 146.6 80.1 (101.8 predicted, -4.4) 2001.03 177.7 114.2 (98.2 predicted, -3.6) 2001.04 177.7 108.2 (97.0 predicted, -1.2) 2001.05 148.6 (1) 112.3 (2) (96.3 predicted, -0.7) 1) Running average based on the daily 20:00 UT solar flux value at 2800 MHz. 2) Unofficial, accumulated value based on the Boulder (SEC/NOAA) sunspot number. The official international sunspot number 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 noted in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ Do you know about the survey which will be held this Summer among the listeners of WWV and WWVH? There is information about this survey at 16 minutes past the hour on WWV and at 47 minutes past the hour on WWVH. If you want to participate send an email with your name and address. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]