Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 19, 2015 at 05:40 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 18. Solar wind speed at SOHO ranged between 358 and 425 km/s.

Solar flux at 23h UTC on 2.8 GHz was 137.3 (increasing 38.2 over the last solar rotation, the measurements at 17 and 20h UT were flare enhanced). The 90 day 10.7 flux at 1 AU was 128.1. The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 5.6). Three hour interval K indices: 22112210 (planetary), 232222** (Boulder).

The background x-ray flux is at the class C1 level.

At the time of counting spots (see image time), spots were observed in 7 active regions using 2K resolution (SN: 190) and 5 active regions using 1K resolution (SN: 121) SDO images on the visible solar disk.

Region 12367 [S20W23] lost penumbral area in the trailing spot section. There is a weak magnetic delta in the northern part of the largest penumbra. A minor M class flare is possible.
Region 12369 [N05W09] decayed slowly and quietly.
Region 12370 [N16W30] was quiet and stable.
Region 12371 [N12E42] developed quickly in the trailing spot section. A large magnetic delta has formed in that part of the region. Further M class flares are likely and a major X class flare is possible.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4543 [S13W52] reemerged with penumbra spots.
S4557 [N18E16] reemerged with penumbra spots.
New region S4559 [N26W09] emerged with a penumbra spot.

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
C7.2 00:24   12367 GOES15  
M1.2 (LDE) 01:27   12365 GOES15 CME, minor proton event, M1.8 @ SDO/EVE
C8.0 02:29   12367 SDO/EVE  
C6.9 02:44   12367 SDO/EVE  
C2.8 05:51 N15E55 12371 GOES15  
C3.3 06:30   12371 SDO/EVE  
C3.5/1F 13:10 N12E47 12371 GOES15  
M3.0/1N (LDE) 17:13 N15E50 12371 GOES15 full halo CME, M3.8 @ SDO/EVE
C3.7 21:47   12371 SDO/EVE  
C2.5 23:37   12371 SDO/EVE  

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

Coronal mass ejections (CMEs)

June 16-17: 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.

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 20-21. CH673 did not cause a significant geomagnetic disturbance during the previous rotation. CH673 has decreased in size since June 16 as a consequence of expanding corona due to the development of AR 12371.

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 to fair.

Forecast

The geomagnetic field is expected to be mostly quiet on June 19-20. Quiet to minor storm conditions are possible on June 21 when the CME observed on June 18 is likely to arrive.

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 57 30 S20W21 0300 EKI EKI

beta-gamma-delta

area: 0400

location: S20W23

S4539 2015.06.11       S10W25            
12369 2015.06.12
2015.06.13
3 5 3 N06W12 0010 BXO BXO

location: N05W09

S4543 2015.06.12   3 2 S13W52 0009   AXX    
12370 2015.06.12
2015.06.14
  2   N17W34 0003   AXX location: N16W30
S4553 2015.06.14       S22W35            
12371 2015.06.15
2015.06.16
26 46 32 N12E39 0810 EKC EKC beta-gamma-delta

area: 1480

location: N12E42

S4557 2015.06.16   6 4 N10W01 0013   AXX    
S4558 2015.06.16       S10W06            
S4559 2015.06.18   1   N36W09 0003   AXX    
Total spot count: 52 120 71  
Sunspot number: 82 190 121  (total spot count + 10 * number of spotted regions)
Weighted SN: 72 140 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): 49 67 67 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 (128.5)   56.5 (2A) / 94.2 (2B) / 62.2 (2C) (49.6 projected, -2.8) (8.5)

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.