Last major update issued on February 13, 2011 at 06:05 UTC. Minor update posted at 11:55 UTC.
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[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-24 (last update February 1, 2011)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update February 1, 2011)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update February 1, 2011)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update February 1, 2011)]
[POES auroral activity level
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Annotated geomagnetic activity charts - Carrington rotation 2104 [Nov-Dec.2010]- 2105 [Dec-Jan.2011] NEW
The geomagnetic field was quiet on February 12. Solar wind speed ranged between 348 and 417 km/s under the influence of a weak coronal hole stream.
Solar flux measured at 20h UTC on 2.8 GHz was 95.6 (increasing 15.3 over the last solar rotation - and a new high for cycle 24). The planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.3). Three hour interval K indices: 12211101 (planetary), 11212110 (Boulder).
The background x-ray flux is at the class B3 level.
At midnight UTC the visible solar disk had 6 spotted regions.
Region 11156 was mostly unchanged and quiet.
Region 11157 developed moderately quickly and could produce C flares.
Region 11158 developed slowly early in the day, then moderately quickly during the latter half of the day. Quick development has been observed early on February 13, and if this development continues, the region will soon become a complex, compact region with major flare potential.
Region 11159 developed slowly. Flare: C2.6 at 15:06 UTC.
New region 11160 rotated partly into view at the northeast limb. Only a single spot was observed at the end of the day, however, early on February 13 more spots are visible. The region displayed quite a bit of activity and appears to have polarity intermixing. C flares are possible and maybe even an M class flare.
Spotted regions not numbered by NOAA/SWPC:
[S877] This region emerged in the northwest quadrant on February 12. Location at midnight: N15W61
Minor update added at 11:55 UTC: Region 11158 continues to develop very quickly and is close to an EKC classification. A strong magnetic delta structure is forming in the center of the region. A major flare, even an X class flare, is possible. Compare the current active region image with the one furtrher below from just over 11 hours ago:
February 10-12: No obviously Earth directed CMEs were observed 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
No significant coronal holes are currently in or near Earth facing positions.
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 February 13-15.
|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.
(Click on image for higher resolution image) Compare to the previous day's image
When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue (blue-green) is positive.
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 / HMI 4K continuum
image with polarity overlay
|Total spot count:||23||70|
|Month||Average measured solar flux||International sunspot number (SIDC)||Smoothed sunspot number||Average ap
|2008.07||65.7 (SF minimum)||0.5||2.8 (-0.4)|
|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||14.0 (+1.7)||10.22 / 10.24|
|2010.05||73.8||8.7||15.5 (+1.5)||9.18 / 8.15|
|2010.06||72.5||13.6||16.4 (+0.9)||8.17 / 6.85|
|2010.07||79.8||16.1||16.8 (+0.4)||6.31 / 5.15|
|2010.08||79.2||19.6||(17.1 predicted, +0.3)||8.49 / 7.77|
|2010.09||81.1||25.2||(17.7 predicted, +0.6)||5.33 / 5.45|
|2010.10||81.6||23.5||(19.0 predicted, +1.3)||6.07 / 6.27|
|2010.11||82.5||21.6||(20.7 predicted, +1.7)||4.80 / 5.50|
|2010.12||84.2||14.5||(22.2 predicted, +1.5)||3.41 / 4.35|
|2011.01||83.6||19.1||(23.8 predicted, +1.6)||4.32|
|2011.02||85.1 (1)||17.7 (2A) / 41.3 (2B)||(25.5 predicted, +1.7)||(6.66)|
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 SIDC international sunspot number is typically 30-50% lower. 2B) Month average to date.
3) Running average based on the preliminary 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.
SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.