Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 19, 2013 at 04:55 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update June 1, 2013)] [Cycle 24 progress (last update June 1, 2013) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update June 1, 2013)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update June 1, 2013)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update June 6, 2013)]

[POES auroral activity level since October 2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated May 12, 2013]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was quiet on June 18. Solar wind speed at SOHO ranged between 271 and 295 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 124.8 (decreasing 8.6 over the last solar rotation). The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.4). Three hour interval K indices: 11111111 (planetary), 11111322 (Boulder).

The background x-ray flux was at the class B4 level.

At midnight UTC the visible solar disk had 10 spotted active regions (in 2K resolution SDO images).

Region 11770 [S14E04] was quiet and stable.
Region 11772 [S20E03] was mostly quiet and stable.
Region 11773 [N03E25] developed slowly and quietly.
Region 11774 [S18E16] decayed slowly and quietly.
Region 11775 [S26E34] still has a magnetic delta structure in the main penumbral structure, however, the region only managed to produce 2 small C flares. M flares are possible.
New region 11776 [N12E04] emerged with several spots and has been unstable. C flares are possible.

Spotted regions not numbered by SWPC:
S2485 [S24E14] developed slowly and quietly.
New region S2487 [S28E06] emerged with a penumbra spot.
New region S2488 [S28E56] emerged with a single spot.
New region S2489 [S18E45] emerged with penumbra spots in an old plage area.

An active region just behind the southeast limb was the source of 2 CMEs observed during the day.

Coronal mass ejections (CMEs)

June 16-18: 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 northern hemisphere coronal hole (CH573) will be in a potentially geoeffective position on June 17-20.

Coronal hole map

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is poor to fair. Propagation on long distance northeast-southwest paths is poor to fair.

Forecast

The geomagnetic field is expected to be quiet on June 19-20. A high speed stream associated with CH573 could start a disturbance late on June 20. Quiet to active conditions with a chance of minor storm intervals are possible on June 21-24.

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: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% 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 STAR SDO SWPC STAR Current Previous
2K 1K
11767 2013.06.07
2013.06.09
      S17W84           plage
11770 2013.06.12
2013.06.13
1 3 1 S15E02 0080 HSX HSX area: 0110
11769 2013.06.12
2013.06.13
      S23W03           merged with AR 11772
11772 2013.06.13
2013.06.14
13 29 13 S22E02 0110 DAI DAI location: S20E03
11771 2013.06.13
2013.06.14
      S15E14         plage
S2478 2013.06.13       N07W45           plage
11773 2013.06.14
2013.06.15
23 39 21 N03E24 0090 CAI DAI area: 0120
11774 2013.06.14
2013.06.15
4 13 5 S19E16 0070 CAO CAO  
11775 2013.06.14
2013.06.15
18 27 11 S26E34 0410 DKC DKC beta-gamma-delta
S2482 2013.06.15       S19E39           plage
S2483 2013.06.15       S25W41           plage
S2484 2013.06.16       S34W36           plage
S2485 2013.06.17   6 2 S24E14 0010   BXO  
S2486 2013.06.17       N13W26         plage
11776 2013.06.18 1 9 5 N11E05 0010   DRO   area: 0060
S2487 2013.06.18   1   S28E06 0002   AXX    
S2488 2013.06.18   1   S28E58 0002   AXX    
S2489 2013.06.18   2   S18E45 0005   BXO    
Total spot count: 60 130 58  
Sunspot number: 120 230 128  (total spot count + 10 * number of spotted regions)
Weighted SN: 90 163 91  (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): 72 81 70 k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for STAR SDO 2K, k = 0.55 for STAR SDO 1K

Monthly solar cycle data

Month Average measured solar flux International sunspot number (SIDC) Smoothed sunspot number Average ap
(3)
2011.11 153.5 (cycle peak) 96.7 (cycle peak) 61.1 (+1.2) 5.55
2012.02 106.5 32.9 66.9 (+1.4)
possible cycle 24 max
8.81
2012.03 114.7 64.3 66.8 (-0.1) 16.08
2012.04 113.0 55.2 64.6 (-2.2) 10.10
2012.05 121.5 69.0 61.7 (-2.9) 7.06
2012.06 119.6 64.5 58.9 (-2.8) 10.08
2012.07 133.9 66.5 57.7 (-1.2) 13.90
2012.08 115.4 63.0 58.1 (+0.4) 7.96
2012.09 122.9 61.4 58.1 (-0.0) 8.07
2012.10 123.3 53.3 58.6 (+0.5) 9.97
2012.11 121.3 61.8 59.7 (+1.1) 7.08
2012.12 108.6 40.8 (59.5 projected, -0.2) 3.44
2013.01 127.1 62.9 (59.1 projected, -0.4) 4.69
2013.02 104.3 38.0 (59.3 projected, +0.2) 6.11
2013.03 111.3 57.9 (58.9 projected, -0.4) 10.56
2013.04 124.8 72.4 (58.6 projected, -0.3) 5.40
2013.05 131.4 78.7 (58.7 projected, +0.1) 9.73
2013.06 106.9 (1) 40.2 (2A) / 66.9 (2B) / 50.6 (2C) (59.0 projected, +0.3) (10.21)

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 SIDC 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 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.