Last major update issued on January 12, 2005 at 03:40 UTC.
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The geomagnetic field was quiet to active on January 11. Solar wind speed ranged between 388 and 464 km/sec. A moderately high speed stream from coronal hole CH138 ended at about 14h UTC. At about 20h UTC a strong high speed stream from coronal hole CH139 arrived at ACE.
Solar flux measured at 20h UTC on 2.8 GHz was 94.2. The planetary A
index was 14 (STAR Ap - based on the mean of three hour interval ap indices: 14.0).
Three hour interval K indices: 14422323 (planetary), 14422323 (Boulder).
The background x-ray flux is at the class B1 level.
At midnight there were 2 spotted regions on the visible solar disk. The solar flare activity level was low. A total of 2 C class events was recorded during the day.Region 10718 developed slowly. The region became more complex as positive polarity flux emerged just ahead of the leading negative polarity spots. C flares are likely. Further development will increase the likelihood of M class flares with associated Earth directed CMEs. Flares: C1.4 at 16:16 and C1.1 at 23:29 UTC.
January 9: A large partial halo CME was observed in LASCO images after the M2 event in region 10718 at 08:51 UTC.
January 10-11: No obvious fully or partly Earth directed CMEs were 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
An extension (CH139) of a large coronal hole in the northern hemisphere was likely in a geoeffective position on January 9-11.
Processed SOHO/EIT 284 image at 01:06 UTC on January 12. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be unsettled to major storm on January 12 and quiet to minor storm on January 13-14 due to a high speed stream from coronal hole CH139. A flanking impact from the CME observed on January 9 is possible on January 12.
|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 fair. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay and an unidentified station from Brazil. On other frequencies propagation was best towards Brazil. CBN Aracajú on 930 kHz had an unusually good signal.
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|
classification was EAO
at midnight, area 0200
this region was deleted
on January 11
classification was DAC
at midnight, area 0170
|Total spot count:||5||34|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2004.07||119.1||51.0||(39.6 predicted, -1.9)|
|2004.08||109.6||40.9||(38.0 predicted, -1.6)|
|2004.09||103.1||27.7||(36.1 predicted, -1.9)|
|2004.10||105.9||48.4||(33.9 predicted, -2.2)|
|2004.11||113.2||43.7||(32.0 predicted, -1.9)|
|2004.12||94.5||17.9||(29.7 predicted, -2.3)|
|2005.01||90.6 (1)||11.4 (2)||(27.0 predicted, -2.7)|
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.