Last major update issued on October 27, 2010 at 03:40 UTC.
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The geomagnetic field was quiet to unsettled on October 26. Solar wind speed ranged between 495 and 640 km/s, under the influence of a high speed stream from CH426.
Solar flux measured at 20h UTC on 2.8 GHz was 86.1 (down 4.6 over the last solar rotation). The planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 7.6). Three hour interval K indices: 32221222 (planetary), 32331221 (Boulder).
The background x-ray flux is at the class B1 level.
At midnight UTC the visible solar disk had 3 spotted regions.
Region 11115 was quiet and stable and is rotating over the southwest
Region 11117 saw lots of changes during the day. A large spot east of the leader spot developed quickly and moved fast westwards eventually merging with the leader spot and forming a large symmetrical penumbra. A large spot formed in the western part of the trailing spot section. Magnetically the region appears to be a little less complex than it was a day ago, however, there is still a chance of an M class flare. Flare: C1.1 at 01:13 UTC.
Region 11119 developed early in the day, then decayed and coudl soon become spotless. Flare: C1.0 at 08:14 UTC.
October 24-25: No obviously Earth directed CMEs were seen in LASCO or STEREO
October 26: A CME was observed starting at about 09h UTC following activity near region 11115. Although the CME will likely not reach Earth, there's a chance of a glancing blow.
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
No obvious coronal holes are currently in or near Earth facing positions.
Image courtesy of SDO (NASA) and the AIA consortium. Annotations are my own. 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 to fair.
The geomagnetic field is expected to be quiet on October 27-28. On October 29 there's a slight chance of unsettled intervals should the CME observed on October 26 reach Earth.
|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||Spot count||Location at midnight||Area||Classification||SDO (NASA) / AIA 4500
|11113||2010.10.13||1||N17W92||0060||HSX||rotated out of view|
|Total spot count:||34||40|
|Month||Average measured solar flux||International sunspot number (SIDC)||Smoothed sunspot number||Average ap
cycle 23 sunspot max.
|2008.07||65.7 (SF minimum)||0.5||2.8 (-0.4)|
|2009.07||68.2||3.2||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||4.3||6.2 (+1.4)||3.88 / 3.61|
|2009.10||72.6||4.8||7.1 (+0.9)||3.66 / 3.56|
|2009.11||73.6||4.1||7.6 (+0.5)||2.45 / 2.63|
|2009.12||76.7||10.8||8.3 (+0.7)||1.41 / 1.92|
|2010.01||81.1||13.2||9.3 (+1.0)||2.93 / 3.07|
|2010.02||84.7||18.8||10.6 (+1.3)||4.15 / 4.61|
|2010.03||83.4||15.4||12.3 (+1.7)||4.58 / 4.65|
|2010.04||75.9||8.0||(13.9 predicted, +1.6)||10.22 / 10.24|
|2010.05||73.8||8.7||(15.2 predicted, +1.3)||9.18 / 8.15|
|2010.06||72.5||13.6||(16.7 predicted, +1.5)||8.17 / 6.85|
|2010.07||79.8||16.1||(18.3 predicted, +1.6)||6.31 / 5.15|
|2010.08||79.2||19.6||(19.5 predicted, +1.2)||8.49 / 7.77|
|2010.09||81.1||25.2||(20.7 predicted, +1.2)||5.33|
|2010.10||81.0 (1)||29.3 (2A) / 34.9 (2B)||(23.1 predicted, +2.4)||(6.64)|
1) Running average based on the
daily 20:00 UTC observed solar flux
value at 2800 MHz.
2A) Current impact on the monthly sunspot number based on the Boulder (NOAA/SWPC) sunspot number (accumulated daily sunspots / month days). The official international sunspot number is typically 30-50% lower. 2B) Month average to date.
3) Running average based on the daily SWPC ap indices. Values in red are based on the official NGDC ap indices.
This report has been prepared by Jan Alvestad. It is based on analysis of data from whatever sources are available at the time the report is prepared. All time references are to the UTC day. Comments and suggestions are always welcome.