Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 28, 2014 at 04:10 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update August 1, 2014)] [Cycle 24 progress (last update August 13, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update August 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update August 1, 2014)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update August 9, 2014)]

[POES auroral activity level October 2009 - December 2012]
[Solar polar fields vs solar cycles - updated July 18, 2014]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]

Recent activity

The geomagnetic field was quiet to active on August 27. Solar wind speed at SOHO ranged between 289 and 351 km/s.

Solar flux at 20h UTC on 2.8 GHz was 123 (decreasing 33.4 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 131.8. The Potsdam WDC planetary A index was 16 (STAR Ap - based on the mean of three hour interval ap indices: 16.3). Three hour interval K indices: 12333443 (planetary), 13444433 (Boulder).

The background x-ray flux is at the class B3 level.

At the time of counting spots (see image time), spots were observed in 10 active regions using 2K resolution (SN: 164) and 8 active regions using 1K resolution (SN: 115) SDO images on the visible solar disk.

Region 12146 [N08W71] still has a significant magnetic delta structure and has the potential to produce a major flare.
Region 12147 [S08W55] decayed slowly and quietly.
Region 12148 [N08W48] decayed slowly and quietly.
Region 12149 [N10W08] decayed slowly in the trailing and intermediate spot sections.
Region 12150 [S13E08] was quiet and stable.
Region 12151 [S07E20] was mostly quiet and unchanged.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3766 [S10E43] was quiet and stable.
S3767 [S17E68] was quiet and stable.
S3768 [N19E11] was quiet and stable.
S3769 [S14W12] developed slowly and quietly.

C2+ Flares (GOES):

Magnitude Peak time (UTC) Location AR
C4.3 03:58 N12E13 12149

Coronal mass ejections (CMEs)

August 25: A full halo CME was observed after the M2 flare in AR 12146. The CME will likely reach Earth on August 28.
August 26-27: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.

Coronal holes

[Coronal hole history (since October 2002)]
[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 (CH632) will rotate into an Earth facing position on August 27-29.

Propagation

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 fair to good.

Forecast

The geomagnetic field is expected to be quiet to minor storm on August 28-29 due to CME effects and quiet to active on August 30-31 under the influence of a high speed stream from CH632.

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 green.
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.

Active solar regions

(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
detected
Spot count Location at midnight Area Classification SDO / HMI 4K continuum
image with magnetic polarity overlay
Comment
SWPC Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
12146 2014.08.16 4 6 4 N07W72 0240 DAI DKC

beta-delta

12147 2014.08.17   1   S08W66 0003   AXX location: S08W55
12148 2014.08.19
2014.08.20
6 5 2 N08W51 0010 BXO AXX

location: N08W48

12149 2014.08.21 13 23 13 N10W04 0160 EAI DHO beta-gamma

location: N10W08

area: 0290

12150 2014.08.22 8 11 6 S14E08 0120 CAO CSO area: 0160
12151 2014.08.22
2014.08.23
1 2 2 S08E19 0140 HAX HAX area: 0230

location: S07E20

S3760 2014.08.23       S16W55           plage
S3763 2014.08.25       N13W19           plage
S3764 2014.08.25       N03E13           plage
S3765 2014.08.26       N13E41         plage
S3766 2014.08.26   2   S10E43 0004   BXO  
S3767 2014.08.26   4 2 S17E68 0015   AXX  
S3768 2014.08.26   3 1 N19E11 0008   BXO  
S3769 2014.08.26   7 5 S14W12 0020   CRO  
Total spot count: 32 64 35  
Sunspot number: 82 164 115  (total spot count + 10 * number of spotted regions)
Weighted SN: 52 97 77  (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): 49 57 63 k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for MSN 2K, k = 0.55 for MSN 1K (MSN=Magnetic Sunspot Number)

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number Average ap
(3)
Measured 1 AU
2013.04 124.8 125.9 72.4 57.9 (+0.4) 5.40
2013.05 131.4 134.3 78.7 59.9 (+2.0) 9.73
2013.06 110.1 113.7 52.5 62.6 (+2.7) 12.60
2013.07 115.5 119.3 57.0 65.5 (+2.9) 9.47
2013.08 114.6 118.3 66.0 69.0 (+3.5) 8.27
2013.09 102.6 103.7 36.9 73.1 (+4.1) 5.23
2013.10  132.1 131.2 85.6 75.0 (+1.9) 7.71
2013.11  148.3 145.1 77.6 75.4 (+0.4) 5.68
2013.12 147.7 143.1 90.3 76.0 (+0.6) 4.68
2014.01 157.4 152.4 81.8 77.3 (+1.3) 5.44
2014.02 170.3
(cycle peak)
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) 4.50
2014.08 125.1 (1)   96.4 (2A) / 110.7 (2B) / 79.3 (2C) (66.5 projected, -3.4) (6.1)

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
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.