Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 14, 2024 at 06:30 UT.

Charts (* = updated daily) Data and archive
  Solar wind (*) Solar and geomagnetic data - last month (*)
  Electron fluence (*) Archived daily reports and monthly data since 2003.01 (June 9, 2024)
Solar cycle Solar cycles 23-25 (June 1, 2024) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (June 1, 2024) Noon SDO sunspot count 1K image / 4K (*)
  Solar cycles 1-24 (July 1, 2020) POES auroral activity level [October 2009 - December 2012]
  Comparison of cycles 21-25 (June 1, 2024) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (June 1, 2024) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (March 3, 2024) Cycle 25 spots (final update December 25, 2019)
  Solar cycles 24-25 transition using 365d smoothing Research: Solar Cycle 25 Started on November 17, 2019 with 365 Days Smoothing
Calculating the Strength of Solar Cycle 25 Using 365-day Smoothing

Recent activity

The geomagnetic field was at very quiet levels on June 13. The high latitude magnetometer at Andenes recorded quiet levels. The above 10 MeV proton flux was at 2 pfu at the end of the day.

Solar flux density measured at 20h UT on 2.8 GHz was 170.1 - decreasing 34.0 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 162.10. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 162.10 on December 14, 2023). The Potsdam WDC planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 2.1). Three hour interval K indices: 00001110 (planetary), 10012311 (Boulder), 20012201 (Andenes).

The background x-ray flux is at the class C1 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 14 active regions using 2K resolution (SN: 287) and in 11 active regions using 1K resolution (SN: 180) SDO/HMI images.

Region 13702 [N17W76] was quiet and stable.
Region 13707 [S13W31] decayed slowly and quietly.
Region 13708 [S21W18] decayed slowly and quietly.
Region 13709 [S09W11] was mostly quiet and stable.
Region 13711 [S10E01] decayed slowly and was mostly quiet.
Region 13712 [S25E39] developed further gaining spots and area as well as a small magnetic delta configuration near the center of the spot group. M class flares are possible.
Region 13713 [S14E56] displayed some development in the leading spot section and produced the larges flares of the day. C1 flares: C1.9 @ 01:28 UT
Region 13714 [N15E12] decayed slowly and was mostly quiet.
Region 13715 [N16E36] decayed slowly and quietly.
Region 13716 [N10E50] developed slowly and quietly.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9778 [N16W56] developed slowly and quietly.
S9789 [N15W26] was quiet and stable.
New region S9799 [N22W62] emerged with tiny spots.
New region S9800 [N29E27] was observed with tiny spots in an old plage area.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.8 06:21   13709 GOES16  
C3.3 07:21   13712 GOES16  
C2.5 07:54   13712 GOES16  
C2.1 12:26   13712 GOES16  
C3.7 13:17 N15E19 13714 GOES16  
C2.8 14:02   13712 GOES16  
C6.7 15:23   13712 GOES16  
C4.6 15:57 S24E46 13712 GOES16  
M3.2/1N 16:45 S16E59 13713 GOES16  
C2.7 18:20   13712 GOES16  
C9.0/1N 18:54 S10W07 13709 GOES16  
C7.8 19:50 S15E56 13713 GOES16  
C2.6 21:17   13712 GOES16  
C2.9 22:18   13713 GOES16  
C2.3 23:22   13712 GOES16  

Coronal mass ejections (CMEs)

June 11-13: No obviously Earth directed CME observed.

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 positive polarity trans equatorial coronal hole (CH1226) will be Earth facing on June 13-14. A positive polarity northern hemisphere coronal hole (CH1227) rotated across the central meridian on June 12.

Propagation

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

Forecast

The geomagnetic field is expected to be quiet to unsettled on June 14 and most of June 15. On June 15 weak effects from CH1227 are possible while June 16-17 could see unsettled to active conditions due to effects from CH1226.

Coronal holes (1) Coronal mass ejections (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). 4K 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 officially numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC, all other regions are numbered sequentially as they emerge using the STAR spot number. 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. SWPC data considered to be not sufficiently precise (location, area, classification) are colored red.

Active region SWPC date numbered
STAR detected
Spot count Location at midnight Area Classification SDO / HMI 4K continuum
image with magnetic polarity overlays
Comment
SWPC/
USAF
Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
13702 2024.06.01
2024.06.02
1 1 1 N17W77 0050 HSX HSX

area: 0130

location: N17W76

13704 2024.06.02
2024.06.03
      S18W74            
S9774 2024.06.05       S27W52            
13707 2024.06.05
2024.06.06
1 12 4 S14W33 0010 AXX BXO

area: 0020

13708 2024.06.05
2024.06.06
1 3 1 S21W19 0040 HAX HAX area: 0080

location: S21W18

S9778 2024.06.06   3 1 N16W56 0010   HRX  
13709 2024.06.06
2024.06.07
8 24 13 S10W12 0120 CAI CSO area: 0200

location: S09W11

S9781 2024.06.07       S22W31          
S9782 2024.06.07       S09W20            
13711 2024.06.07
2024.06.09
1 16 7 S09W02 0010 AXX CRO beta-gamma

location: S10E01

area: 0035

13714 2024.06.08
2024.06.12
  14 6 N14E10 0025   BXO location: N15E12
S9786 2024.06.08       S23W50            
S9789 2024.06.09   3   N15W26 0005   AXX  
S9791 2024.06.10       S24W06            
13715 2024.06.11
2024.06.12
  3 2 N17E35 0010   BXO location: N16E36
13712 2024.06.11
2024.06.12
18 33 12 S24E38 0240 DAC DAC beta-gamma-delta

area: 0460

13713 2024.06.11
2024.06.12
9 20 9 S13E54 0170 DSO DSI location: S14E56

area: 0340

S9796 2024.06.11       N27E22          
S9797 2024.06.11       S04W44            
S9798 2024.06.11       S20E07            
13716 2024.06.12 5 10 5 N10E48 0060 DAO DAO area: 0250
S9799 2024.06.13   2   N22W62 0004   AXX    
S9800 2024.06.13   3   N29E27 0004   AXX    
Total spot count: 44 147 70  
Sunspot number: 124 287 180  (total spot count + 10 * number of spotted regions)
Weighted SN: 74 183 106  (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): 136 158 144  

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number (4) Average ap
(3)
Measured 1 AU
2014.02 170.3
(cycle peak)
166.3 146.1 (SC24 peak) 110.5 10.70
2014.04 143.9 144.8 112.5 116.4 (SC24 solar max) 7.88
2017.09 91.3 92.3 43.6 18.2 (-1.3) 18.22
(SC24 peak)
2019.11 70.2 68.7 0.5 2.0 (-0.6)
(Solar minimum using 365d smoothing:
November 17, 2019)
4.19
2019.12 70.8 68.6 1.6 1.8 (-0.2)
(ISN 13 months smoothed
solar minimum)
3.22
2022.10 133.5 132.7 95.5 98.9 (+2.4) 11.16
2022.11 123.4 120.7 80.5 101.2 (+2.3) 9.33
2022.12 147.9 143.4 112.8 106.7 (+5.5) 10.99
2023.01 182.4 176.6 144.4 113.3 (+6.6) 8.73
2023.02 167.2 163.2 111.3 117.8 (+3.5) 14.48
2023.03 157.2 155.6 123.3 121.1 (+3.3) 14.42
2023.04 145.4 146.4 97.6 122.9 (+1.8) 13.40
2023.05 155.6 159.2 137.4 124.2 (+1.3) 10.67
2023.06 161.7 166.8 160.5 125.3 (+1.1) 8.95
2023.07  176.4 182.2 160.0 124.4 (-0.9) 8.15
2023.08  153.7 157.6 114.8 124.1 (-0.3) 7.19
2023.09  154.4 156.0 134.2 123.9 (-0.2) 14.26
2023.10  142.8 141.9 99.4 124.8 (+0.9) 8.16
2023.11 153.5 150.2 105.4 127.8 (+3.0) 12.20
2023.12 151.1 146.4 114.2 (128.7 projected, +0.9) 9.60
2024.01 164.6 159.3 123.0 (127.0 projected, -1.7) 5.46
2024.02 172.5 168.3 124.7 (126.2 projected, -0.8) 5.31
2024.03 154.4 152.9 104.9 (125.6 projected, -0.6) 11.03
2024.04 161.3 162.6 136.5 (125.6 projected, -0.0) 9.69
2024.05 187.7
(cycle peak)
191.9 171.7 (SC25 peak) (126.7 projected, +1.1) 23.56
(current
SC25 peak)
2024.06 182.0 (1)   69.7 (2A) / 160.8 (2B) / 169.0 (2C) (125.9 projected, -0.8) (8.3)
2024.07       (124.2 projected, -1.7)  
2024.08       (122.2 projected, -2.0)  
2024.09       (121.0 projected, -1.2)  
2024.10       (119.6 projected, -1.4)  
2024.11       (114.5 projected, -5.1)  
2024.12       (109.1 projected, -5.4)  

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz and any corrections applied to that measurement.
2A) Current impact on the monthly sunspot number based on the Boulder (NOAA/SWPC) sunspot number (accumulated daily sunspots / month days).
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.
4) Source: WDC-SILSO, Royal Observatory Of Belgium, Brussels

Solar cycles 24-25

Smoothed SF and sunspot numbers

Update on the progress of solar cycle 25 as of June 6, 2024

May 2024 easily became the month with the highest sunspot counts during solar cycle 25, and early June has seen no change in that pattern of many spot groups, some of which are large and complex. The next candidate for solar max is still uncertain, however, May 20-21, 2024 has all of the smoothed 365d sunspot numbers as well as the 365d smoothed solar flux signalling a peak on those days.

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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 Universal Time. Comments and suggestions are always welcome.

SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.