Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 21, 2015 at 04:35 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 very quiet on June 20. Solar wind speed at SOHO ranged between 272 and 326 km/s.

Solar flux at 20h UTC on 2.8 GHz was 135.4 (increasing 36.7 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 128.6. The Potsdam WDC planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 1.6). Three hour interval K indices: 00000001 (planetary), ******** (Boulder).

The background x-ray flux is at the class B7 level.

At the time of counting spots (see image time), spots were observed in 8 active regions using 2K resolution (SN: 171) and 3 active regions using 1K resolution (SN: 89) SDO images on the visible solar disk.

Region 12367 [S20W52] decayed quickly in the trailing spot section. The region still has polarity intermixing and could produce a minor M class flare.
Region 12369 [N06W34] decayed slowly and quietly.
Region 12370 [N17W61] was quiet and stable.
Region 12371 [N12E15] has a large magnetic delta in the trailing penumbra. The region produced a single M1 flare on June 20 and 2 M2 flares early on June 21, at least one of the M2 flares was associated with a halo CME. A major flare is possible.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4543 [S13W80] decayed slowly and quietly.
S4557 [N13W16] was quiet and stable.
New region S4562 [S03W12] was observed with a penumbra spot.
New region S4563 [S09E49] emerged with a penumbra spot.

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
C2.3 02:42 N14E27 12371 GOES15  
M1.0/1F 06:48 N13E25 12371 GOES15 C9.0 @ SDO/EVE
C3.2 07:40   12367 SDO/EVE also recorded by San Vito
C2.5 08:05   12367 SDO/EVE also recorded by San Vito

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

Coronal mass ejections (CMEs)

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.
June 20: No obviously Earth directed CMEs were observed.
June 21
: A halo CME was observed after an M2 flare in AR 12371 early in day. The CME will likely reach Earth on June 23

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) was in 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 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 to minor storm on June 21-23 due to the arrival of the CMEs observed on June 18 and 19. The CME observed early on June 21 will likely arrive on June 23 and could increase the disturbance level to major storm. A high speed stream from CH673 could complicate the geomagnetic disturbance situation on June 23.

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
34 35 26 S20W49 0290 EKI DAI

beta-gamma

location: S20W52

S4539 2015.06.11       S10W51            
12369 2015.06.12
2015.06.13
  2   N06W42 0004   BXO

location: N06W34

S4543 2015.06.12   1 1 S13W80 0004   BXO  
12370 2015.06.12
2015.06.14
  1   N17W62 0002   AXX  
12371 2015.06.15
2015.06.16
35 48 32 N13E14 1120 EKC FKC beta-gamma-delta

location: N12E15

S4557 2015.06.16   2   N13W16 0006   AXX  
S4558 2015.06.16       S10W32            
S4559 2015.06.18       N36W35            
S4560 2015.06.19       S23E23          
S4562 2015.06.20   1   S03W12 0003   AXX    
S4563 2015.06.20   1   S09E44 0002   AXX    
Total spot count: 69 91 59  
Sunspot number: 89 171 89  (total spot count + 10 * number of spotted regions)
Weighted SN: 89 111 79  (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): 53 60 49 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 (129.3)   62.0 (2A) / 93.0 (2B) / 62.0 (2C) (49.6 projected, -2.8) (8.0)

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.