Last major update issued on March 28, 2008 at 05:15 UTC.
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The geomagnetic field was quiet to major storm on March 27. Solar wind speed ranged between 541 and 701 km/s under the influence of a high speed stream from CH317/CH318.
Solar flux measured at 20h UTC on 2.8 GHz was 84.8. The planetary A index was 31 (STAR Ap - based on the mean of three hour interval ap indices: 30.6). Three hour interval K indices: 65433245 (planetary), 54432334 (Boulder).
The background x-ray flux is at the class A3 level.
At midnight there were 3 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 10987 decayed slowly and quietly.
Region 10988 was quiet and mostly unchanged.
Region 10989 decayed slightly and was quiet.
March 25-27: No partially or fully Earth directed CMEs were observed.
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 trans equatorial coronal hole (CH318) was Earth facing on March 25-28.
Processed SOHO/EIT 195 image at 00:24 UTC on March 28. The darkest areas on the solar disk are likely coronal holes.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is very poor. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet to minor storm on March 28-29 due to effects from CH318 and quiet to unsettled on March 30-31.
|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.
Compare to the previous day's image.
Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC. 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 SWPC or where SWPC has observed no spots. SWPC active region numbers in the table below and in the active region map above are the historic SWPC/USAF numbers.
|Active region||Date numbered||SWPC
|Location at midnight||Area||Classification||Comment|
|10987||2008.03.23||11||9||S07W05||0170||DAI||classification was DAO at midnight|
|Total spot count:||27||21|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2007.09||67.1||1.9||(5.7 predicted, -0.3)|
|2007.10||67.4||0.9||(5.9 predicted, +0.2)|
|2007.11||69.6||1.7||(6.2 predicted, +0.3)|
|2007.12||78.5||10.1||(6.4 predicted, +0.2)|
|2008.01||74.3||3.4||(6.9 predicted, +0.5)|
|2008.02||71.1||2.1||(7.9 predicted, +1.0)|
|2008.03||71.6 (1)||9.5 (2)||(9.3 predicted, +1.4)|
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/SWPC) 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.