Last major update issued on February 10, 2008 at 05:30 UTC.
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The geomagnetic field was quiet on February 9. Solar wind speed ranged between 357 and 428 km/s. The early part of a high speed stream from CH312 arrived at approximately 18h UTC at ACE. A geomagnetic disturbance began early on February 10.
Solar flux measured at 20h UTC on 2.8 GHz was 72.2. The planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 2.8). Three hour interval K indices: 10002111 (planetary), 00013221 (Boulder).
The background x-ray flux is below the class A1 level.
At midnight there was 1 spotted region on visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.
Spotted regions not numbered by NOAA/SWPC:
[S719] This region emerged in the northeast quadrant on February 9. Location at midnight: N03E35.
February 7-9: 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 coronal hole (CH312), mainly in the southern hemisphere, will rotate into an Earth facing position on February 6-11.
Processed SOHO/EIT 195 image at 00:00 UTC on February 10. 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 fair. Propagation on long distance northeast-southwest paths is poor.
Monitoring remarks from a location near N58E06: January 1: Good signals were noted on most TA frequencies in widespread conditions as even a few west coast stations surfaced. Several stations from México had strong signals as did 1570 HRRF. The best Trans Atlantic propagation sector was 270-300 degrees.
The geomagnetic field is expected to be quiet to active on February 10-11 due to a high speed stream associated with CH312, minor storm intervals are possible on February 10. Quiet to unsettled conditions are likely on February 12-14.
|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|
|Total spot count:||0||1|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2007.08||69.1||5.7||(6.1 predicted, -0.9)|
|2007.09||67.1||1.9||(6.0 predicted, -0.1)|
|2007.10||67.4||0.9||(6.5 predicted, +0.5)|
|2007.11||69.6||1.7||(6.9 predicted, +0.4)|
|2007.12||78.5||10.1||(7.1 predicted, +0.2)|
|2008.01||74.3||3.4||(7.6 predicted, +0.5)|
|2008.02||70.9 (1)||2.2 (2)||(8.6 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/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.