Last major update issued on December 14, 2004 at 04:00 UTC.
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The geomagnetic field was quiet to active on December 13. Solar wind speed ranged between 350 and 472 km/sec. A weak flow from coronal hole CH132 arrived late in the day and has so far been associated with a mostly northwards interplanetary magnetic field.
Solar flux measured at 20h UTC on 2.8 GHz was 89.7. The planetary A
index was 11 (STAR Ap - based on the mean of three hour interval ap indices: 10.9).
Three hour interval K indices: 43311211 (planetary), 44312311 (Boulder).
The background x-ray flux is at the class A8 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 10711 decayed slightly as penumbra on the trailing spots disappeared. There is still a chance of C flares.Spotted regions not numbered by NOAA/SEC:
[S488] A single spot emerged in the warm plage area in the southeast quadrant on December 13. Location at midnight:
S15E40
December 11-13: No obviously Earth directed CMEs observed.
Coronal hole history (since late October 2002)
Compare today's report with the situation one solar rotation ago: 28
days ago 27 days ago 26 days ago
Coronal hole CH132 in the southern hemisphere may have been in a geoeffective position on December 9-10. An extension (CH133) of the northern polar coronal hole could reach a marginally geoeffective position on December 13.
Processed SOHO/EIT 284 image at 18:03 UTC on December 11. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on December 14-15. On December 16 effects from coronal hole CH133 could reach Earth with quiet to active conditions likely.
| 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) 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.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is very poor. Propagation along long distance north-south paths is poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay and Radio Vibración (Venezuela). Only a few stations from Brazil and Venezuela were heard on other frequencies.
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 |
|---|---|---|---|---|---|---|---|
| 10709 | 2004.12.03 | N07W66 | plage | ||||
| 10710 | 2004.12.08 | S08W17 | plage | ||||
| 10711 | 2004.12.10 | 12 | 14 | N13W60 | 0120 | DAI |
classification was CAI at midnight, area 0090 |
| S488 | emerged on 2004.12.13 |
1 | S15E40 | 0000 | AXX | ||
| Total spot count: | 12 | 15 | |||||
| SSN: | 22 | 35 | |||||
| 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) |
| 2003.10 | 151.7 | 65.5 | 58.2 (-1.3) |
| 2003.11 | 140.8 | 67.3 | 56.7 (-1.5) |
| 2003.12 | 114.9 | 46.5 | 54.8 (-1.9) |
| 2004.01 | 114.1 | 37.3 | 52.0 (-2.8) |
| 2004.02 | 107.0 | 45.8 | 49.3 (-2.7) |
| 2004.03 | 112.0 | 49.1 | 47.1 (-2.2) |
| 2004.04 | 101.2 | 39.3 | 45.5 (-1.6) |
| 2004.05 | 99.8 | 41.5 | 43.9 (-1.6) |
| 2004.06 | 97.4 | 43.2 | (42.2 predicted, -1.7) |
| 2004.07 | 119.1 | 51.0 | (40.6 predicted, -1.6) |
| 2004.08 | 109.6 | 40.9 | (39.0 predicted, -1.6) |
| 2004.09 | 103.1 | 27.7 | (37.1 predicted, -1.9) |
| 2004.10 | 105.9 | 48.4 | (34.9 predicted, -2.2) |
| 2004.11 | 113.2 | 43.7 | (33.0 predicted, -1.9) |
| 2004.12 | 93.6 (1) | 16.8 (2) | (30.7 predicted, -2.3) |
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% less.
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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