Last major update issued on June 20, 2014 at 03:45 UTC.
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[Solar cycles 23-24 (last update June 1, 2014)] [Cycle 24 progress (last update June 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update June 1, 2014)]
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2009 - December 2012]
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[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]
The geomagnetic field was quiet to unsettled on June 19. Solar wind speed at SOHO ranged between 407 and 536 km/s.
Solar flux at 17h UTC on 2.8 GHz was 104.6 (decreasing 11.9 over the last solar rotation, the measurement at 20h UTC was enhanced by a long duration event). The 90 day 10.7 flux at 1 AU was 139.3. The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 7.6). Three hour interval K indices: 33221122 (planetary), 33322322 (Boulder).
The background x-ray flux is at the class B2 level.
At the time of counting spots (see image time), spots were observed in 7 active regions using 2K resolution (SN: 117) and 7 active regions using 1K resolution (SN: 101) SDO images on the visible solar disk.
Region 12087 [S19W48] decayed slowly and quietly
Region 12090 [N25W37] was quiet and stable.
Region 12092 [S18W35] was quiet and stable.
Region 12093 [S10E19] has begun to interact with the trailing polarity area of AR S3538. Further development is possible and there is a chance of a minor M class flare.
Region 12094 [S18E31] was quiet and stable.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3538 [S09E22] developed in the trailing spot section and could be meerging with AR 12093.
New region S3556 [N11E10] emerged with a penumbra spot.
|Magnitude||Peak time (UTC)||Location||AR|
June 19: A filament eruption began just after 15h UTC just north of ARs
12093/S3538. A partial halo CME was observed, the CME could have Earth directed
June 18: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
June 17: A partial halo CME was observed after a C4 flare in AR 12087. The CME could have weak Earth directed components.
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 Earth facing positions.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is poor to fair.
The geomagnetic field is expected to be mostly quiet on June 20-21. On June 22-23 there is a chance of a weak disturbance associated with the CME observed on June 19.
|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: 0-30% probability, Yellow: 30-70% probability, Red: 70-100% probability.
(Click on image for 2K resolution) Compare to the previous day's image. 0.5K image
When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue 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
rotated out of view
|Total spot count:||38||47||31|
|Sunspot number:||108||117||101||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||69||73||57||(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):||65||41||56||k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for MSN 2K, k = 0.55 for MSN 1K (MSN=Magnetic Sunspot Number)|
|Month||Average solar flux||International sunspot number
|Smoothed sunspot number||Average ap
|2013.12||147.7||143.1||90.3||(75.8 projected, +0.4)||4.68|
|2014.01||157.4||152.4||82.0||(76.4 projected, +0.6)||5.44|
|166.3||102.8 (cycle peak)||(76.2 projected, -0.2)||10.70|
|2014.03||149.9||148.5||92.2||(76.6 projected, +0.4)||4.88|
|2014.04||143.9||144.8||84.7||(75.8 projected, -0.8)||7.88|
|2014.05||129.7||132.9||75.2||(73.2 projected, -2.6)||5.75|
|2014.06||131.2 (1)||78.7 (2A) / 124.2 (2B) / 78.9 (2C)||(70.5 projected, -2.7)||(7.6)|
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 WDC-SILSO international sunspot number is typically 30-50% lower. 2B) Boulder SN current month average to date. 2C) STAR SDO 1K Wolf number 30 day average.
3) Running average based on the quicklook and definitive Potsdam WDC ap indices. Values in red are based on the definitive international GFZ Potsdam WDC ap indices.
This report has been prepared by Jan Alvestad. It is based on the 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.