Last major update issued on December 5,
2006 at 04:40 UTC. Minor update posted at 10:45 UTC on Dec.5. Huge
geomagnetic data - last month (updated daily)]
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[Solar cycles 21-23 (last update November 12, 2006)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update November 12, 2006)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update November 12, 2006)]
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[Archived reports (last update November 12, 2006)]
The geomagnetic field was very quiet on December 4. Solar wind speed ranged between 288 and 330 km/s (all day average 307 km/s - decreasing 25 km/s from the previous day).
Solar flux measured at 22h UTC on 2.8 GHz was 96.3. The planetary A index was 1 (STAR Ap - based on the mean of three hour interval ap indices: 1.3). Three hour interval K indices: 00000101 (planetary), 00000100 (Boulder).
The background x-ray flux is at the class B3 level.
At midnight there were 4 spotted regions on the visible solar disk. The solar flare activity level was low. A total of 12 C class events was recorded during the day.
Region 10926 decayed slowly and quietly.
Region 10927 decayed and was quiet.
New region 10929 emerged near the northeast limb.
New region 10930 began to rotate into view at the southeast limb. This region is very active and produced an amazing 10 C flares during the latter half of the day. An M class flare is likely. Early GONG magnetograms indicate that the region is magnetically complex (as would be expected from the flare activity) Flares: C1.2 at 12:15, C1.4 at 12:42, C4.9 at 14:39, C1.1 at 15:55, C1.3 at 16:17, C1.2 at 17:10, C1.2 at 20:43, C1.4 at 21:27, C1.0 at 23:17 and C2.2 at 23:30 UTC.
Comment added at 10:45 UTC on Dec.5:
Region 10930 produced an amazing X9.0 flare at 10:35 UTC. It is very
unusual for flares of this size to occur near solar minimum. This flare
occurred while the region is still at the east limb and an Earth
directed CME is not very likely.
December 2-4: No obvious partly or fully Earth directed CMEs were detected in very incomplete LASCO imagery.
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 recurrent coronal hole (CH250) in the southern hemisphere was in an Earth facing position on December 3-4.
Processed SOHO/EIT 284 image at 19:06 UTC on November 24. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet on December 5. A high speed stream from CH250 could cause a disturbance on December 6-7 with unsettled to major storm conditions.
|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 very poor to poor. Propagation on long distance northeast-southwest paths is very poor.
Monitoring remarks from a location near N58E06: Propagation was similar to the previous 2 nights with very few North American stations audible and not much to hear from the Caribbean or South America either.
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
|Location at midnight||Area||Classification||Comment|
|10929||2006.12.04||2||2||N02E67||0030||BXO||area was 0010 at midnight|
|Total spot count:||13||15|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2006.06||76.5||13.9||(16.3 predicted, -1.0)|
|2006.07||75.7||12.2||(14.7 predicted, -1.6)|
|2006.08||79.0||12.9||(14.2 predicted, -0.5)|
|2006.09||77.8||14.5||(14.1 predicted, -0.1)|
|2006.10||74.3||10.4||(13.0 predicted, -1.1)|
|2006.11||86.3||21.5||(11.5 predicted, -1.5)|
|2006.12||88.7 (1)||6.5 (2)||(11.3 predicted, -0.2)|
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.