Solar Terrestrial Activity Report [Image] Last update May 11, 2000 at 05:05 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 10. Solar wind speed ranged between 315 and 342 km/sec. Solar flare activity was low. Solar flux was 179.2 (influenced by a long duration event in region 8990), the planetary A index was 7 (3-hour K indices: 3212 2222, Boulder K indices: 2210 1111). Region 8980 was quiet and stable and rotated off the visible disk early today. Region 8982 was mostly quiet and stable and will rotate over the west limb on May 12. Regions 8983 and 8987 were quiet and stable. Region 8986 developed quickly late in the day and is capable of minor M class flaring. (SEC/NOOA deleted region 8986 and renumbered it as region 8993. The reasons for this action are unknown and were probably just a mistake.) Region 8989 developed slowly and could produce C flares and minor M flares. Region 8990 developed slowly and has improved its flare potential to the minor M class level. Region 8991 developed slowly and could generate C class flares. Region 8992 was quiet and stable. New region 8994 emerged just to the south of region 8989. An active and interesting region is rotating into view at the southeast limb. Flares and CMEs A total of 5 C flares were observed on May 10. Region 8989 produced a C1.3 flare at 02:09 and another C1.3 flare at 08:19 UTC. Region 8990 generated the most significant event of the day, a long duration C8.7/2N event peaking at 19:41 UTC. A strong type II sweep and a weak type IV sweep were observed as well. A CME covering the entire eastern hemisphere was seen in LASCO C2 images. At the same time a CME was observed off the southwest limb and was probably associated with a filament eruption in the southwest quadrant and not with the LDE in region 8990. Anyway there is a fair chance Earth could receive a CME impact on May 14. May 8: A large filament eruption across the central meridian in the southern hemisphere was in progress at 06:12 UTC in LASCO EIT images. A partial halo coronal mass ejection was observed from 06:48 UTC in LASCO C2 images. There is a possibility of a terrestrial impact on May 11 or early on May 12. The background x-ray flux is at the class C1 level. Coronal holes A small well placed coronal hole in the southern hemisphere was in a geoeffective position on May 8-9. Forecast The geomagnetic field is expected to be quiet to active on May 11 due to possible coronal stream effects and a possible CME impact. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair. 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 8980 20000428 2 S20W88 0040 AXX 8981 20000501 S22W82 plage 8982 20000503 6 S23W73 0030 DSO 8983 20000504 3 N26W21 0010 BXO 8984 20000505 S13W54 plage 8985 20000505 N12W14 plage 8986 20000505 12 S23W06 0050 DAI 8987 20000507 1 N10W34 0010 HRX 8988 20000507 N08W43 plage 8989 20000507 19 N16W01 0180 DAI 8990 20000507 16 N14E20 0070 DAI 8991 20000508 8 N15E46 0110 DAO 8992 20000509 1 N09E60 0050 HSX 8994 20000510 6 N11W01 0030 CRO Total number of sunspots: 74 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 (109.8 predicted, +2.1) 1999.12 169.8 84.6 (108.2 predicted, -1.6) 2000.01 158.1 90.2 (108.6 predicted, +0.4) 2000.02 174.1 112.3 (112.0 predicted, +3.4) 2000.03 208.2 138.2 (115.8 predicted, +3.8) 2000.04 184.2 125.3 2000.05 143.6 (1) 40.8 (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]