Last major update issued on October 24, 2006 at 04:10 UTC.
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The geomagnetic field was very quiet on October 24. Solar wind speed ranged between 463 and 556 km/s (all day average 499 km/s - decreasing 57 km/s from the previous day).
Solar flux measured at 20h UTC on 2.8 GHz was 76.4. The planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 2.6). Three hour interval K indices: 10011111 (planetary), 10012222 (Boulder).
The background x-ray flux is at the class A2 level.
At midnight there were 2 spotted regions on the visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.
Region 10917 decayed quickly and quietly.
New region 10918 emerged just west of region 10917.
October 21-23: No obvious partly or fully Earth directed CMEs were detected in LASCO imagery.
Coronal hole history (since late October 2002)
Compare today's report to the situation one solar rotation ago:
28 days ago
27 days ago
26 days ago
A large Y-shaped trans equatorial coronal hole (CH245) - where the southwestern part was formerly CH241 - will be in an Earth facing position on October 24-25. The central part is poorly defined.
Processed SOHO/EIT 284 image at 19:06 UTC on October 23. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet on October 24-26. On October 27-29 quiet to active conditions are likely due to effects from CH245.
Coronal holes (1) | Coronal mass ejections (2) | M and X class flares (3) |
1) Effects from a coronal hole could reach Earth
within the next 5 days. When the high speed stream has arrived the color changes to green.
2) Effects from a CME are likely to be observed at 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.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is good. Propagation on long distance northeast-southwest paths is poor.
Monitoring remarks from a location near N58E05: A number of strong signals were heard from stations along the east coast of North America, particularly stations from Florida and New York were impressive. Not often received stations like 980 WHSR and 1020 WRHB were easily audible.
Compare to the previous day's image.
Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SEC. Comments are my own, as is the STAR spot count (spots observed at or inside a few hours before midnight) and data for regions not numbered by SEC or where SEC has observed no spots. SEC active region numbers in the table below and in the active region map above are the historic SEC/USAF numbers.
Active region | Date numbered | SEC spot count |
STAR spot count |
Location at midnight | Area | Classification | Comment |
---|---|---|---|---|---|---|---|
10917 | 2006.10.19 | 24 | 14 | S05W60 | 0160 | DAI | classification was DSI at midnight, area 0100 |
10918 | 2006.10.23 | 6 | 2 | S04W72 | 0050 | CRO | classification was HAX at midnight, area 0030 |
Total spot count: | 30 | 16 | |||||
SSN: | 50 | 36 |
Month | Average solar flux at Earth |
International sunspot number | Smoothed sunspot number |
---|---|---|---|
2000.04 | 184.2 | 125.5 | 120.8 cycle 23 sunspot max. |
2000.07 | 202.3 | 170.1 | 119.8 |
2001.12 | 235.1 | 132.2 | 114.6 (-0.9) |
2005.08 | 90.5 | 36.4 | 27.4 (-1.7) |
2005.09 | 91.1 | 21.9 | 25.8 (-1.6) |
2005.10 | 77.0 | 8.7 | 25.5 (-0.3) |
2005.11 | 86.3 | 18.0 | 24.9 (-0.6) |
2005.12 | 90.7 | 41.1 | 23.0 (-1.9) |
2006.01 | 83.4 | 15.3 | 20.8 (-2.2) |
2006.02 | 76.5 | 4.9 | 18.6 (-2.2) |
2006.03 | 75.4 | 10.6 | 17.3 (-1.3) |
2006.04 | 89.0 | 30.2 | (17.1 predicted, -0.2) |
2006.05 | 80.9 | 22.2 | (16.8 predicted, -0.3) |
2006.06 | 76.5 | 13.9 | (15.1 predicted, -1.7) |
2006.07 | 75.7 | 12.2 | (13.2 predicted, -1.9) |
2006.08 | 79.0 | 12.9 | (12.8 predicted, -0.4) |
2006.09 | 77.8 | 14.5 | (12.6 predicted, -0.2) |
2006.10 | 74.2 (1) | 11.2 (2) | (11.6 predicted, -1.0) |
1) Running average based on the
daily 20:00 UTC observed solar flux
value at 2800 MHz.
2) Unofficial, accumulated value based on the Boulder (NOAA/SEC)
sunspot number. The official international sunspot number is typically
30-50% lower.
This report has been prepared by Jan Alvestad. It is based partly on my own observations and analysis, and partly on data from some of these solar data sources. All time references are to the UTC day. Comments and suggestions are always welcome.
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