Last major update issued on March 18, 2010 at 05:10 UTC.
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The geomagnetic field was quiet to active on March 17. Solar wind speed ranged between 400 and 510 km/s under the influence of a moderately high speed stream.
Solar flux measured at 20h UTC on 2.8 GHz was 86.7. The planetary A index was 7 (STAR Ap - based on the mean of three hour interval ap indices: 7.3). Three hour interval K indices: 14210013 (planetary), 13221112 (Boulder).
The background x-ray flux is at the class A7 level.
At midnight there were 2 spotted regions on the visible solar disk.
Region 11054 decayed further losing all trailing spots.
New region 11056 emerged in the northeast quadrant.
March 15-17: No obvious Earth directed CMEs were observed in LASCO or
March 14: A partial halo CME was observed in LASCO images early in the day after a C1.5 flare in region 11054 at 23:36 UTC on March 13. The CME was complex with mass ejected near region 11054, across the central meridian and into the northwest limb. Actually there may have been two CMEs occurring at nearly the same time and it is uncertain if the apparent single CME observed in LASCO images is actually two distinct CMEs.
Coronal hole 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 small coronal hole (CH396) in the southern hemisphere was in an Earth facing position on March 14-15.
Processed SOHO/EIT 195 image at 23:12 UTC on March 17. 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 poor. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet to unsettled with a chance of active intervals on March 18-19 due to coronal hole effects. If the CME observed on March 14 arrives, active and minor storm intervals will be possible on March 18. Quiet conditions are likely on March 20.
|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||SWPC
|11054||2010.03.10||4||6||N15W37||0070||CAI||classification was CSO at midnight
|Total spot count:||8||11|
|Month||Average measured solar flux||International sunspot number (SIDC)||Smoothed sunspot number||Average ap
cycle 23 sunspot max.
|2009.07||68.2||3.5||3.6 (+0.9)||5.49 / 4.55|
|2009.08||67.3||0.0||4.8 (+1.2)||5.70 / 4.89|
|2009.09||70.5||4.2||(6.4 predicted, +1.6)||3.88 / 3.61|
|2009.10||72.6||4.6||(8.3 predicted, +1.9)||3.66 / 3.56|
|2009.11||73.6||4.2||(10.3 predicted, +2.0)||2.45 / 2.63|
|2009.12||76.7||10.6||(12.4 predicted, +2.1)||1.41 / 1.92|
|2010.01||81.1||13.1||(15.0 predicted, +2.6)||2.93 / 3.07|
|2010.02||84.7||18.6||(17.9 predicted, +2.9)||4.15 / 4.61|
|2010.03||82.4 (1)||13.1 (2)||(21.1 predicted, +3.2)||(5.0)|
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.
3) Running average based on the daily SWPC ap indices. Values in red are based on official NGDC ap indices.
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.