Last major update issued on November 29, 2011 at 04:30 UTC.
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[Solar cycles 21-24 (last update November 1, 2011)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update November 1, 2011)]
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[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update November 2, 2011)]
[POES auroral activity level since October
2009 - updated November 28, 2011]
Annotated geomagnetic activity charts - Carrington rotation 2114 [August-September 2011] - 2115 [September-October 2011]
[Solar polar fields vs solar cycles - updated June 27, 2011]
The geomagnetic field was quiet to active on November 28. Solar wind speed ranged between 338 and 539 km/s. A moderately strong solar wind shock was observed at SOHO at 21:27 UTC, the arrival of the CME observed on November 26.
Solar flux measured at 20h UTC on 2.8 GHz was 137.6 (decreasing 1.0 over the last solar rotation). The planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.9). Three hour interval K indices: 00000004 (planetary), 00002214 (Boulder).
The background x-ray flux is at the class B5 level.
At midnight UTC the visible solar disk had 10 spotted regions (in 2K resolution SDO images).
Region 11353 [N08W76] decayed slowly and had only a tiny spot left at
the end of the day.
Region 11355 [N15W61] was quiet and stable.
Region 11356 [N17W37] decayed further retaining only negative polarity spots. Flare: C1.2 at 21:47 UTC
Region 11358 [N21E02] decayed slowly and quietly.
Region 11361 [N19E22] developed slowly and had many small spots. C flares are possible and further development could create a compact region capable of producing M class flares. Flare: C3.2 at 18:30 UTC
Region 11362 [N08E65] developed slowly and could produce C and maybe a minor M class flare. Flare: C1.4 at 23:09 UTC
Spotted regions not reported by NOAA/SWPC:
[S1338] emerged in the northeast quadrant on November 26. Location at midnight: N15E33
[S1339] rotated partly into view at the southeast limb on November 28. This could be two regions, however, the spots are too close to the limb to determine this with certainty. Location at midnight: S19E83
[S1340] rotated partly into view at the northeast limb on November 28. A single penumbra was barely visible against the limb. Location at midnight: N20E89
[S1341] emerged in the southwest quadrant on November 28. Location at midnight: S23W55
November 26: A filament eruption across the solar equator stretching from
northwest of region 11354 to the northwest of region 11353 was
observed beginning at 05:58 UTC on Nov.26 and was the source of a long duration
C1.2 event peaking at 07:10. This event was associated with a significant
increase in proton fluxes and a large full halo CME. While Earth does not appear
to be in the path of the core CME, a flank impact is very likely.
November 27: A filament eruption near the center of the visible disk was observed beginning at 11:12 UTC. A small and slow moving CME was observed beginning at 11:24 UTC in STEREO-A images, this CME preceeded a larger backsided CME.
November 28: No obviously Earth directed CMEs observed.
Coronal hole history (since late October
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago
A coronal hole (CH486) in the southern hemisphere was in an Earth facing position on November 26-27.
The above coronal hole map is based on a new method where coronal holes are detected automatically. The method may need some fine tuning, however, it has significant advantages over detecting coronal holes manually. The main improvement is the ability to detect coronal holes at and just beyond the solar limbs. Early results using this method for SDO images over a span of several weeks indicate a good match between coronal holes observed over the visible disk and their extent and position at the east and west limbs. Note that the polar coronal holes are easily detected using the new method, the extent and intensity of both holes are consistent with other data sources.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is very poor. Propagation on long distance northeast-southwest paths is poor to fair.
The geomagnetic field is expected to be unsettled to minor storm on November 29 due to CME effects, there's a chance of isolated major storm intervals. Quiet to unsettled conditions are likely on Nov.30 and December 1 due to coronal hole effects.
|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
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 magnetic polarity overlay
|S1339||2011.11.28||3||S19E83||0250||HSX||maybe 2 regions|
|Total spot count:||30||72|
|Sunspot number:||90||172||(total spot count + 10 * number of spotted regions)|
|Weighted penumbral SN:||60||105||(Sum of total spot count + classification weighting for each AR. Classification weighting: X=0, R=3, A/S=5, H/K=10)|
|Relative sunspot number (Wolf number):||54||77||k * (sunspot number). k = 0.6 for SWPC. k = 0.45 (changed from 0.33 on Nov.1) for STAR SDO|
|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)|
|2010.07||79.8||16.1||16.7 (+0.3)||6.31 / 5.15|
|2010.08||79.2||19.6||17.4 (+0.7)||8.49 / 7.77|
|2010.09||81.1||25.2||19.6 (+2.2)||5.33 / 5.45|
|2010.10||81.6||23.5||23.2 (+3.6)||6.07 / 6.27|
|2010.11||82.5||21.5||26.5 (+3.3)||4.80 / 5.50|
|2010.12||84.2||14.4||28.8 (+2.3)||3.41 / 4.35|
|2011.01||83.6||19.1||31.0 (+2.2)||4.32 / 5.51|
|2011.02||94.6||29.4||33.4 (+2.4)||5.41 / 6.44|
|2011.03||115.0||56.2||36.9 (+3.5)||7.79 / 8.18|
|2011.04||112.6||54.4||41.8 (+4.9)||9.71 / 8.83|
|2011.05||95.8||41.6||(47.4 predicted, +5.6)||9.18 / 8.94|
|2011.06||95.8||37.0||(52.5 predicted, +5.1)||8.96 / 8.06|
|2011.07||94.2||43.9||(58.2 predicted, +5.7)||9.14 / 8.16|
|2011.08||101.7||50.6||(63.7 predicted, +5.5)||8.16 / 7.26|
|2011.09||133.8||78.0||(67.0 predicted, +3.3)||12.80 / 12.27|
|2011.10||137.3||88.0||(70.5 predicted, +3.5)||7.52|
|2011.11||154.3 (1)||125.4 (2A) / 134.4 (2B)||(74.9 predicted, +4.4)||(4.23)|
1) Running average based on the daily 20:00 UTC observed solar flux value at
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.