Last major update issued on July 14, 2012 at 06:15 UTC.
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The geomagnetic field was very quiet on July 13. Solar wind speed at SOHO ranged between 326 and 375 km/s.
Solar flux measured at 20h UTC on 2.8 GHz was 147.2 (increasing 12.7 over the last solar rotation). The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 2.9). Three hour interval K indices: 11110000 (planetary), 11001211 (Boulder).
The background x-ray flux is at the class C1 level.
At midnight UTC the visible solar disk had 10 spotted active regions (in 2K resolution SDO images).
Region 11519 [S16W45] was quiet and stable.
Region 11520 [S17W18] displayed only minor changes and remains capable of producing another major flare.
Region 11521 [S22W35] decayed in the trailing spot section, however, new flux emerged centrally and the region became compact. M flares are possible.
Region 11522 [N11W34] displayed no major changes and was quiet.
Region 11523 [S28E31] developed slowly and quietly.
Spotted active regions not numbered or interpreted differently by NOAA/SWPC:
S1776 [S16W27] decayed slowly and quietly.
S1777 [S12W21] was quiet and stable.
S1785 [S26W45] was quiet and stable.
New region S1795 [N21E44] emerged with a single spot.
New region S1796 [S31W10] emerged with tiny spots in an old plage area.
The most interesting activity of the day was observed just before midnight as a flare from a region about a day behind the southeast limb.
July 11, 13: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
July 12: The X1 LDE in AR11520 was associated with a large and very wide CME. The core of the CME is likely Earth directed and could reach Earth before noon on July 14.
Coronal hole history (since October
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago
No obvious potentially geoeffective coronal holes are currently in or near Earth facing positions.
The above coronal hole map is based on a method where coronal holes are detected automatically. While the method may need some fine tuning, 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 this method, the extent and intensity of both CHs 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 poor. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet early on July 14. The CME observed on July 12 could reach Earth near noon on July 14 and cause minor to very severe geomagnetic storming lasting 18-30 hours. Quiet to active is likely on July 16.
|Coronal holes (1)||Coronal mass ejection (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
SWPC count, location, classification and area probably includes ARs S1776 and S1777
|Total spot count:||62||136||60|
|Sunspot number:||112||236||130||(total spot count + 10 * number of spotted regions)|
|Weighted penumbral SN:||97||172||93||(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):||67||83||72||k * (sunspot number). k = 0.6 for SWPC, k = 0.35 (changed from 0.45 on March 1, 2011) for STAR SDO 2K, k = 0.55 for STAR SDO 1K|
|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)|
|2012.01||132.5||58.3||(65.0 projected, +1.6)||7.15|
|2012.02||106.5||33.1||(66.5 projected, +1.5)||8.81|
|2012.03||114.7||64.2||(67.2 projected, +0.7)||16.08|
|2012.04||113.0||55.2||(66.5 projected, -0.7)||10.10|
|2012.05||121.5||69.0||(64.8 projected, -1.7)||7.06|
|2012.06||119.6||64.5||(64.0 projected, -0.8)||10.08|
|2012.07||156.5 (1)||53.4 (2A) / 127.4 (2B)||(65.0 projected, +1.0)||(16.34)|
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 quicklook and definitive Potsdam WDC ap indices. Values in red are based on the definitive international Potsdam WDC 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.