Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 20, 2015 at 05:45 UT.

Charts (* = updated daily) Data and archive
  Solar wind (*) Solar and geomagnetic data - last month (*)
  Electron fluence (*) Archived daily reports and monthly data from 2003.01 (June 1, 2015)
Solar cycle Solar cycles 23-24 (June 1, 2015) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24 progress (June 1, 2015) Noon SDO sunspot count 1K Reference: 4K (large file) (*)
  Solar cycles 1-20 POES auroral activity level October 2009 - December 2012
  Comparison of cycles 21, 22, 23 and 24 (June 1, 2015) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 10, 12, 13, 14, 16 and 24 (June 1, 2015) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs solar cycles (June 8, 2015)  

Recent activity

The geomagnetic field was quiet on June 19. Solar wind speed at SOHO ranged between 286 and 381 km/s.

Solar flux at 20h UTC on 2.8 GHz was 137.3 (increasing 39.6 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 128.4. The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.9). Three hour interval K indices: 21110000 (planetary), ******** (Boulder).

The background x-ray flux is at the class B5 level.

At the time of counting spots (see image time), spots were observed in 7 active regions using 2K resolution (SN: 192) and 5 active regions using 1K resolution (SN: 116) SDO images on the visible solar disk.

Region 12367 [S20W38] decayed slowly. The region has polarity intermixing and could produce a minor M class flare.
Region 12369 [N05W23] decayed slowly and quietly.
Region 12370 [N13W48] was quiet and stable.
Region 12371 [N12E29] gained penumbral area in the trailing spot section. There is still a magnetic delta in a large trailing penumbra, however, opposite polarity umbrae are currently not very close. Still, there is a chance of a major flare.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4543 [S13W67] was quiet and stable.
S4557 [N21E05] was quiet and stable.
New region S4560 [S23E30] was observed with a penumbra spot.

A large filament eruption in the southern hemisphere beginning near 05 UT was associated with a partial halo CME.

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
C2.8 (LDE) 01:19   12371 GOES15  
C2.1 (LDE) 03:14   12371 GOES15  
C8.1 09:27 N15E39 12371 GOES15 C7.0 @ SDO/EVE

Flare activity (SDO/EVE/ESP XRS-B proxy)

Coronal mass ejections (CMEs)

June 17: No obviously Earth directed CMEs were observed.
June 18: A full halo CME was observed after the M3 event in AR 12371. The CME could reach Earth on June 21.
June 19: A partial halo CME caused by a large filament eruption in the suthern hemisphere could reach Earth on June 22.

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 northern hemispere coronal hole (CH673) will likely rotate into an Earth facing position on June 19-20. CH673 did not cause a significant geomagnetic disturbance during the previous rotation. CH673 decreased in size June 16-18, but became much larger following a filament eruption in the southern hemisphere on June 19.

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 poor.

Forecast

The geomagnetic field is expected to be quiet on June 20. Quiet to minor storm conditions are possible on June 21-23 due to the arrival of the CMEs observed on June 18 and 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 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 overlays
Comment
SWPC Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
12367 2015.06.10
2015.06.11
23 53 27 S20W35 0300 EKI EAI

beta-gamma

location: S20W38

S4539 2015.06.11       S10W38            
12369 2015.06.12
2015.06.13
  3   N06W27 0010   AXX

location: N05W23

S4543 2015.06.12   5 4 S13W67 0013   BXO  
12370 2015.06.12
2015.06.14
  1   N17W48 0002   AXX location: N13W48
S4553 2015.06.14       S22W48            
12371 2015.06.15
2015.06.16
31 54 32 N13E27 1020 EKC EKC beta-gamma-delta

area: 1850

location: N12E29

S4557 2015.06.16   5 2 N10W01 0014   BXO  
S4558 2015.06.16       S10W19            
S4559 2015.06.18       N36W22          
S4560 2015.06.19   1 1 S23E36 0004   AXX    
Total spot count: 54 122 66  
Sunspot number: 74 192 116  (total spot count + 10 * number of spotted regions)
Weighted SN: 74 137 81  (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): 44 67 64 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
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) 78.4 (+1.1) 10.70
2014.03 149.9 148.5 91.9 80.8 (+2.4) 4.88
2014.04 143.9 144.8 84.7 81.9 (+1.1) (solar max) 7.88
2014.05 129.7 132.9 75.2 80.5 (-1.4) 5.75
2014.06 122.0 125.8 71.0 79.7 (-0.8) 6.72
2014.07 137.4 141.8 72.5 78.5 (-1.2) 4.50
2014.08 124.7 127.9 74.7 75.5 (-3.0) 7.71
2014.09 146.6 148.1 87.6 70.8 (-4.7) 9.78
2014.10 153.4 152.9 60.6 67.3 (-3.5) 8.96
2014.11 154.8 151.4 70.1 65.4 (-1.9) 9.33
2014.12 158.7 153.8 78.0 (63.5 projected, -1.9) 11.24
2015.01 141.9 137.3 67.0 (61.3 projected, -2.2) 9.46
2015.02 129.1 126.0 44.8 (59.6 projected, -1.7) 9.92
2015.03 125.9 124.6 38.4 (57.2 projected, -2.4) 16.14
2015.04 128.8 129.7 54.4 (54.6 projected, -2.6) 10.73
2015.05 120.0 122.6 58.8 (52.4 projected, -2.2) 8.29
2015.06 (129.0)   59.0 (2A) / 93.2 (2B) / 62.1 (2C) (49.6 projected, -2.8) (8.3)

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.