Last major update issued on August 2, 2014 at 07:35 UTC.
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[Solar cycles 23-24 (last update August 1, 2014)] [Cycle 24 progress (last update July 1, 2014) ]
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[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]
The geomagnetic field was quiet to unsettled on August 1. Solar wind speed at SOHO ranged between 285 and 420 km/s. A disturbance was observed arriving at ACE near 18h UTC, based on EPAM data the source of the disturbance was likely a CME.
Solar flux at 20h UTC on 2.8 GHz was 168 (decreasing 25.0 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 134.0. The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 7.8). Three hour interval K indices: 21122133 (planetary), 22133434 (Boulder).
The background x-ray flux is at the class B9 level.
At the time of counting spots (see image time), spots were observed in 16 active regions using 2K resolution (SN: 358) and 15 active regions using 1K resolution (SN: 255) SDO images on the visible solar disk.
Region 12121 [N07W65] decayed slowly and quietly.
Region 12125 [S14W08] decayed slowly and quietly.
Region 12126 [S09W69] decayed slowly and quietly.
Region 12127 [S07E08] gained spots, none of the trailing polarity spots have umbra. Further minor M class flares are possible.
Region 12128 [S21E08] was quiet and stable.
Region 12130 [S07E27] developed slightly and produced several flares. C and M class flaring is likely.
Region 12131 [S19E19] developed slowly and quietly.
Region 12132 [S19E45] developed quickly and could produce M class flares.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3680 [N13W23] was quiet and stable.
S3686 [N11W04] was quiet and stable.
S3691 [N09W69] was quiet and stable.
S3692 [N08W76] was quiet and stable.
New region S3695 [N18E75] rotated into view.
New region S3696 [S05E38] emerged with a few spots.
New region S3698 [N09E82] rotated partially into view.
New region S3700 [S07E18] emerged with a few spots.
|Magnitude||Peak time (UTC)||Location||AR|
A filament eruption across the central meridian and to the north of the equator was observed beginning at 10:28 UTC in SDO/AIA imagery. This event was associated with a partial halo CME which could reach Earth on August 4.
A weak halo CME was associated with the M1.5 flare in AR 12127. The CME could reach Earth on August 4.
August 1: A filament eruption in the northern hemisphere 10:30-13:00 UTC was
associated with a partial halo CME. The CME could reach Earth on August 4. A
weak halo CME was observed after an M1 flare in AR12127. The CME could reach
Earth late on August 4.
July 31: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
July 30: A filament eruption in the northeast quadrant after 05h UTC was associated with a partial halo CME. This CME could reach Earth on August 2.
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
A recurrent trans equatorial coronal hole (CH629) was in an Earth facing position on July 31-August 1.
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 quiet to active on August 2-5 due to CME and coronal hole effects.
|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
|Total spot count:||75||198||105|
|Sunspot number:||165||358||255||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||115||245||152||(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):||99||125||140||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
|166.3||102.3 (cycle peak)||(78.1 projected, +0.8)||10.70|
|2014.03||149.9||148.5||91.9||(79.0 projected, +0.9)||4.88|
|2014.04||143.9||144.8||84.7||(78.1 projected, -0.9)||7.88|
|2014.05||129.7||132.9||75.2||(75.6 projected, -2.5)||5.75|
|2014.06||122.0||125.8||71.0||(72.9 projected, -2.7)||6.72|
|2014.07||137.4||141.8||72.5||(69.9 projected, -3.0)||4.5|
|2014.08||168 (1)||5.3 (2A) / 165 (2B) / 83.9 (2C)||(66.5 projected, -3.4)||(7.8)|
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.