Last major update issued on May 15, 2011 at 04:50 UTC.
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Annotated geomagnetic activity charts - Carrington rotation 2108 [March-April 2011] - 2109 [April-May 2011] NEW
The geomagnetic field was quiet on May 14. Solar wind speed ranged between 295 and 356 km/s. A coronal hole stream associated with CH448 was observed arriving at ACE near 21h UTC.
Solar flux measured at 20h UTC on 2.8 GHz was 91.4 (decreasing 23.0 over the last solar rotation). The planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.5). Three hour interval K indices: 11000112 (planetary), 11001222 (Boulder).
The background x-ray flux is at the class B1 level.
At midnight UTC the visible solar disk had 7 spotted regions.
Region 11208 developed as new flux emerged. The region currently has
Region 11210 decayed slowly and quietly.
New region 11213 emerged in the southwest quadrant on May 11 and was noticed by NOAA/SWPC 3 days later. The region decayed on May 14 and is rotating over the southwest limb.
New region 11214 emerged in the southeast quadrant on May 13 and was numbered by SWPC the next day. The region developed slowly on May 14.
New region 11215 emerged on May 12 and got an SWPC number 2 days later.
Spotted regions not numbered by NOAA/SWPC:
[S1004] emerged in the northeast quadrant on May 13. Location at midnight: N06E04
[S1008] emerged with tiny spots in an old plage area in the northeast quadrant on May 14. Location at midnight: N17E26
May 12-14: No obviously Earth directed CMEs were observed in LASCO
and STEREO imagery.
May 11: A filament eruption to the west of region 11207 early in the day was associated with a partial halo CME. Weak effects from this CME could reach Earth on May 14 or 15.
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 trans equatorial coronal hole (CH448) was in an Earth facing position on May 11-12. An extension (CH449) of the southern polar coronal hole was Earth facing on May 14-15. This extension has weakened significantly over the last couple of days and could be closing.
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 May 15 with a chance of active intervals due to effects from CH448. Mostly quiet conditions are likely on May 16 while May 17-18 could see quiet to active conditions caused by a high speed stream from CH449.
|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 polarity overlay
|1||1||S21W80||0000||AXX||AXX||formerly region S1000|
|2||3||S23W30||0020||BXO||BXO||formerly region S1001|
formerly region S1005
|Total spot count:||14||39|
|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)|
|2010.02||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||16.7 (+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||(26.9 predicted, +3.7)||4.80 / 5.50|
|2010.12||84.2||14.4||(30.1 predicted, +3.2)||3.41 / 4.35|
|2011.01||83.6||19.1||(33.1 predicted, +3.0)||4.32 / 5.51|
|2011.02||94.6||29.4||(35.6 predicted, +2.5)||5.41 / 6.44|
|2011.03||115.0||56.2||(37.9 predicted, +2.3)||7.79|
|2011.04||112.6||54.4||(40.8 predicted, +2.9)||9.71|
|2011.05||100.9 (1)||29.1 (2A) / 64.4 (2B)||(44.1 predicted, +3.3)||(7.34)|
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.