Last major update issued on August 14, 2010 at 04:30 UTC. Minor update posted at 11:50 UTC.
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The geomagnetic field was quiet on August 13. Solar wind speed ranged between 330 and 454 km/s.
Solar flux measured at 20h UTC on 2.8 GHz was 83.7. The planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.5). Three hour interval K indices: 12011111 (planetary), 12011111 (Boulder).
The background x-ray flux is at the class B1 level.
At midnight UTC the visible solar disk had 4 spotted regions.
Region 11093 decayed slowly and quietly.
Region 11097 reemerged with a couple of tiny spots.
Region 11098 decayed slowly and was quiet. The region could soon become spotless.
New region 11099 was observed with spots on August 12 and numbered by NOAA/SWPC the next day. This region is quite interesting as it is developing quickly. Positive magnetic flux emerged inside and in the eastern part of the negative leading polarity area. Further development will quickly increase the chance of C and even M class flares.
Update posted at 11:50 UTC on August 14: A C4.4 long duration event peaking at 10:05 UTC with an origin in region 11099 was a minor proton flare. Significant proton flares are possible if the region continues to grow.
August 11-13: No obviously Earth directed CMEs were seen in LASCO or STEREO images.
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, elongated, trans equatorial coronal hole (CH417) was Earth facing on August 11.
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 poor to fair. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet on August 14. Late on August 14 and on August 15 there's a chance of a few unsettled intervals due to effects from CH417. Quiet conditions are likely on August 16.
|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
|11099||2010.08.13||13||13||N17W41||0010||BXO||DRI||formerly region S799
|Total spot count:||21||22|
|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 predicted, +1.3)||4.15 / 4.61|
|2010.03||83.4||15.4||(12.3 predicted, +1.7)||4.58 / 4.65|
|2010.04||75.9||7.9||(13.9 predicted, +1.6)||10.22 / 10.24|
|2010.05||73.8||8.8||(15.3 predicted, +1.4)||9.18 / 8.15|
|2010.06||72.5||13.5||(16.7 predicted, +1.4)||8.17 / 6.85|
|2010.07||79.8||16.1||(18.3 predicted, +1.6)||6.31|
|2010.08||82.3 (1)||17.5 (2A) / 41.7 (2B)||(19.5 predicted, +1.2)||(10.22)|
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 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.