Last major update issued on July 28, 2010 at 04:20 UTC.
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The geomagnetic field was unsettled to active on July 27. Solar wind speed ranged between 453 and 687 km/s under the influence of a high speed stream from CH415.
Solar flux measured at 20h UTC on 2.8 GHz was 82.6. The planetary A index was 19 (STAR Ap - based on the mean of three hour interval ap indices: 19.0). Three hour interval K indices: 33443343 (planetary), 33433433 (Boulder).
The background x-ray flux is at the class B1 level.
At midnight there were 2 spotted regions on the visible solar disk.
Region 11089 decayed slowly losing penumbra on the trailing spots. Flare: C2.2 at 04:24 UTC
Spotted regions not numbered by NOAA/SWPC:
[S793] This region rotated partly into view at the northeast limb on July 27. Location at midnight: N14E84
July 25-27: 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 recurrent coronal hole (CH415) in the northern hemisphere was Earth facing on July 21-26.
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. Propagation on long distance northeast-southwest paths is poor to fair.
The geomagnetic field is expected to be quiet to active on July 28-30 due to effects from CH415.
|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
|Total spot count:||5||6|
|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||(9.2 predicted, +0.9)||2.93 / 3.07|
|2010.02||84.7||18.8||(10.4 predicted, +1.2)||4.15 / 4.61|
|2010.03||83.4||15.4||(12.1 predicted, +1.7)||4.58 / 4.65|
|2010.04||75.9||7.9||(13.7 predicted, +1.6)||10.22 / 10.24|
|2010.05||73.8||8.8||(15.0 predicted, +1.3)||9.18 / 8.15|
|2010.06||72.5||13.5||(16.4 predicted, +1.4)||8.17 / 6.85|
|2010.07||79.2 (1)||19.6 (2)||(18.0 predicted, +1.6)||(5.95)|
1) Running average based on the
daily 20:00 UTC observed solar flux
value at 2800 MHz.
2) 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.
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.