Last major update issued on June 16, 2012 at 05:15 UTC.
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The geomagnetic field was very quiet on June 15. Solar wind speed at SOHO ranged between 283 and 342 km/s.
Solar flux measured at 20h UTC on 2.8 GHz was 144.9 (increasing 14.0 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: 3.0). Three hour interval K indices: 01011111 (planetary), 00011221 (Boulder).
The background x-ray flux is at the class B4 level.
At midnight UTC the visible solar disk had 8 spotted active regions (in 2K resolution SDO images).
Region 11504 [S17W11] had most of the smaller spots in the
southeastern section merge into a larger penumbra. There are still two magnetic
delta structures in this part of the region. M flares are possible.
Region 11505 [S11W14] decayed significantly and was quiet.
Region 11506 [N10W03] decayed slowly and quietly.
Region 11507 [S28W35] was mostly quiet although. There's minor polarity intermixing and a slight chance of an M class flare.
New region 11509 [S16W29] emerged on June 10 and got the attention of SWPC 5 days later.
Spotted active regions not numbered or interpreted differently by NOAA/SWPC:
S1719 [S25W22] was quiet and stable.
S1721 [N09W34] reemerged with a few tiny spots.
S1729 [N17E03] reemerged with small spots.
June 13: A partial halo CME was observed after the M1.2 LDE in AR 11504.
This CME could reach Earth on June 16.
June 14: A large symmetrical full halo CME was associated with the M1.9 LDE in AR 11504. This CME could reach Earth during the latter half of June 16.
June 15: No obvious CMEs were observed in LASCO and STEREO imagery.
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 coronal holes are currently in or near potentially geoeffective 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 fair. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be initially quiet on June 16. Late in the day the CME observed on June 14 is likely to arrive causing active to major storm conditions with a chance of severe storm intervals. The CME observed on June 13 could arrive a few hours ahead of the larger CME. Quiet to unsettled conditions are likely on June 18.
|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 considers this to be two regions
|11508||2012.06.13||9||S28W31||0050||CAO||part of AR 11507|
|Total spot count:||53||130||69|
|Sunspot number:||113||210||139||(total spot count + 10 * number of spotted regions)|
|Weighted penumbral SN:||81||154||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):||68||74||76||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)|
|2011.12||141.3||73.0||(64.3 projected, +3.2)||3.78|
|2012.01||132.5||58.3||(68.0 projected, +3.7)||7.15|
|2012.02||106.5||33.1||(71.3 projected, +3.3)||8.81|
|2012.03||114.7||64.2||(73.0 projected, +1.7)||16.08|
|2012.04||113.0||55.2||(73.2 projected, +0.2)||10.10|
|2012.05||121.5||69.0||(73.2 projected, +0.0)||8.75|
|2012.06||133.3 (1)||61.2 (2A) / 122.4 (2B)||(73.9 projected, +0.7)||(11.78)|
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.