Solar Terrestrial Activity Report [Image] Last update June 26, 2000 at 05:45 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update June 2, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update June 2, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update June 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 June 25. Solar wind speed ranged between 416 and 529 km/sec. A disturbance started just before midnight. Solar wind speed at ACE increased from 430 to 560 km/sec from 23:30 to 00:30 UTC and there was a significant increase in the total field of the interplanetary magnetic field. Wind speed quickly decreased after 00:30 UTC and has since been in the 450 to 500 km/sec range. Solar flare activity was moderate. Solar flux was 175.1, the planetary A index was 8 (3-hour K indices: 3111 2234, Boulder K indices: 1111 2333). Region 9046 was mostly unchanged and could produce occasional C or minor M class flares. Region 9049 decayed slowly but could produce additional C class flares. Region 9054 developed quickly and could produce minor M class flares. Regions 9055, 9056 and 9057 were quiet and stable. Region 9058 developed at a moderate pace and should have minor M class flaring potential. Region 9059 was quiet and stable, as were regions 9060 and 9061. New region 9062 rotated partly into view at the southeast limb and may be capable of generating minor M class flares. Flares and CMEs A total of 6 C flares and 2 M flares were observed on June 25. Region 9042 produced an M2.5 flare at 01:14 UTC. Region 9046 was the source of an M1.9/2N long duration event peaking at 07:52 UTC. This was a weak proton producing event as well. Region 9049 generated a C7.7/1N flare at 13:57 UTC while region 9054 managed a C1.9 flare at 23:32 UTC. Quite a few CMEs were observed from late on June 24 until early on June 26. Most of the CMEs were caused by activity near the solar limbs and will likely not influence the geomagnetic field. A large CME spanning from the northeast to the northwest limb over the north pole is in progress early on June 26. June 23: A filament to the north and east of region 9051 erupted at 07:13 UTC in LASCO-EIT images. Parts of the filament was over the central meridian at the time of the eruption. An apparently full halo CME was observed later in LASCO C2 images. The CME could impact Earth on June 26, however, the expected presence of a coronal stream at that time will likely mean that the CME will add little to the ongoing geomagnetic activity. There is a chance the CME could arrive just before the coronal stream in which case initial activity could reach minor storm levels. The background x-ray flux is at the class B8 level. Coronal holes A well defined coronal hole in the southern hemisphere was in a geoeffective position on June 23-26. Forecast The geomagnetic field is expected quiet to minor storm on June 26-27. 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 9046 20000614 8 N21W61 0110 CSO 9049 20000616 10 S35W48 0080 CAO 9051 20000617 N13W44 plage 9053 20000619 N04W32 plage 9054 20000620 17 N12W04 0130 DAO 9055 20000621 2 N19E17 0070 HSX 9056 20000621 1 S14E15 0230 HSX 9057 20000622 1 N13E33 0200 HSX 9058 20000623 16 S14W41 0140 DAO 9059 20000623 7 N15E04 0020 CRO 9060 20000624 2 S32E46 0010 BXO 9061 20000624 1 S15E59 0050 HSX 9062 20000625 2 S19E72 0080 DSO Total number of sunspots: 67 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 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) 1999.11 191.5 133.2 110.9 (+3.2) 1999.12 169.8 84.6 (111.2 predicted, +0.3) 2000.01 158.1 90.2 (112.4 predicted, +1.2) 2000.02 174.1 112.3 (115.8 predicted, +3.4) 2000.03 208.2 138.2 (119.6 predicted, +3.8) 2000.04 184.2 125.3 (121.7 predicted, +2.1) 2000.05 184.9 120.8 2000.06 181.8 (1) 153.6 (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]