Last major update issued on February 19, 2011 at 07:00 UTC.
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Annotated geomagnetic activity charts - Carrington rotation 2104
[Nov-Dec.2010]- 2105
[Dec-Jan.2011] NEW
The geomagnetic field was quiet to minor storm on February 18. Solar wind speed ranged between 298 and 644 km/s. A solar wind shock was observed at SOHO at 00:40 UTC, the arrival of the CME associated with the X2 flare observed on February 15. This could have been a significant disturbance, however, the interplanetary magnetic field was predominantly northwards resulting in the peak disturbance level only reaching minor storm.
Solar flux measured at 20h UTC on 2.8 GHz was 124.8 (increasing 37.1 over the last solar rotation). The planetary A index was 17 (STAR Ap - based on the mean of three hour interval ap indices: 17.4). Three hour interval K indices: 34533321 (planetary), 34433332 (Boulder).
The background x-ray flux is at the class B9 level.
At midnight UTC the visible solar disk had 6 spotted regions.
Region 11158 decayed slowly. The central part of the region is still
very complex and another major flare is possible.
Flares: C1.7 at 01:08, C8.5 at 06:33, major M6.6 at 10:11 (flare
location confirmed by this
EVE image, others have attributed the flare to region 11162), M1.4 at 13:03,
C4.0 at 14:32, C5.0 at 15:05 and C3.2 at 18:21 UTC.
Region 11160 (SWPC duplicate number is 11161) extended with the addition
of tiny trailing spots, polarity intermixing increased.
New region 11162 emerged in the northeast quadrant near region 11160 on
February 17 and was numbered the following day by NOAA/SWPC. The region was very
unstable and has produced a number of C and M flares. The magnetic layout of the
region is complex and further flaring is likely.
Flares: C2.0 at 03:34, C4.0 at 04:51, C7.6 at 07:24, C4.2 at
09:11, M1.0 at 10:26, C3.0 at 12:20, M1.0 at 14:08, C5.5 at 15:55, C2.3 at
16:39, C2.1 at 16:45, C3.8 at 17:53, C7.1 at 19:18 and M1.3 at 21:04 UTC.
Spotted regions not numbered by NOAA/SWPC:
[S878] This region emerged in the northeast quadrant on February 13. Location at midnight:
N21W19
[S880] This region reemerged with tiny spots on February 16 and still had
a tiny spot on February 18. Location at midnight: N07W54
[S883] A tiny spot emerged in this region in the southwest quadrant on
February 18. Location at midnight: S20W24
February 16: No Earth directed CMEs were observed. A filament eruption in
region S878 around 06-07 UTC produced a CME off the northeast limb.
February 17-18: No obviously Earth directed CME were observed in LASCO and
STEREO imagery.
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. Propagation on long distance northeast-southwest paths is poor to fair.
The geomagnetic field is expected to be quiet to unsettled on February 19 and quiet on February 20-21.
| 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 detected |
Spot count | Location at midnight | Area | Classification | SDO / HMI 4K continuum image with polarity overlay |
Comment | |||
|---|---|---|---|---|---|---|---|---|---|---|
| SWPC | STAR | SWPC | STAR | Current | Previous | |||||
| 11158 | 2011.02.11 2011.02.10 |
25 | 32 | S19W64 | 0310 | EHC | ESC |
 |
|
beta-gamma-delta |
| 11159 | 2011.02.11 2011.02.10 |
N19W67 | plage | |||||||
| S875 | 2011.02.10 | N20W51 | plage | |||||||
| S876 | 2011.02.11 | S17W20 | plage | |||||||
| 11160 | 2011.02.12 | 28 | 35 | N12W02 | 0200 | EAI | FAI |
 |
 |
beta-gamma SWPC: 11161 |
| S878 | 2011.02.13 | 1 | N21W19 | 0000 | AXX |
 |
 |
|||
| S880 | 2011.02.14 | 1 | N07W54 | 0000 | AXX |
 |
 |
|||
| 11162 | 2011.02.18 2011.02.17 |
18 | 29 | N18W06 | 0260 | DAI | DAI |
 |
 |
formerly region S882 |
| S883 | 2011.02.18 | 1 | S20W24 | 0000 | AXX |
 |
||||
| Total spot count: | 71 | 99 | ||||||||
| Sunspot number: | 101 | 159 | ||||||||
| Month | Average measured solar flux | International sunspot number (SIDC) | Smoothed sunspot number | Average ap (3) |
|---|---|---|---|---|
| 2008.07 | 65.7 (SF minimum) | 0.5 | 2.8 (-0.4) | |
| 2008.12 | 69.2 | 0.8 | 1.7 (-) sunspot minimum |
3.25 |
| 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 | 94.6 (1) | 35.1 (2A) / 54.6 (2B) | (25.5 predicted, +1.7) | (6.33) |
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.
