Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 8, 2024 at 09:25 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 (May 1, 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 quiet to severe storm levels on June 7. The high latitude magnetometer at Andenes recorded quiet to major storm levels. Another CME was the likely source of a relatively brief and intense disturbance that was observed beginning at ACE at 10:50 UT. The above 10 MeV proton flux was at background levels at the end of the day, but increased rapidly to a peak of 1030 pfu at 08:00 UT on June 8 following a major proton flare in AR 13697.

Solar flux density measured at 20h UT on 2.8 GHz was 184.4 - decreasing 29.3 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 161.72. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 161.72 on December 8, 2023). The Potsdam WDC planetary A index was 31 (STAR Ap - based on the mean of three hour interval ap indices: 31.4). Three hour interval K indices: 23247633 (planetary), 13235533 (Boulder), 44246524(Andenes).

The background x-ray flux is at the class C3 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 16 active regions using 2K resolution (SN: 304) and in 12 active regions using 1K resolution (SN: 184) SDO/HMI images.

Region 13697 [S19W58] developed again after several days of slow decay. A major M9.7 flare was recorded 01:49 UT on June 8 and the associated partial halo CME was dense and could reach Earth on June 10.
Region 13698 [N22W69] decayed slowly and quietly.
Region 13701 [S06W55] decayed slowly and quietly.
Region 13702 [N17E05] developed slowly and quietly as new flux emerged.
Region 13703 [S08W35] decayed slowly and quietly.
Region 13704 [S18E08] was quiet and stable.
Region 13707 [S15E47] developed slowly and was mostly quiet.
Region 13708 [S22E59] was mostly quiet and stable.
New region 13709 [S10E67] rotated into view on June 6 and was numbered by SWPC the next day. M flares are possible.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9769 [N09E18] decayed slowly and quietly.
S9771 [N36E04] was quiet and stable.
S9778 [N26E29] was quiet and stable.
New region S9780 [S21W78] emerged with tiny spots.
New region S9781 [S25E48] emerged with tiny spots.
New region S9782 [S08E58] emerged with tiny spots.
New region S9783 [S08E81] rotated into view with a few spots.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C7.5 00:32 S19W47 13697 GOES16  
C4.8 00:59   13709 GOES16  
C5.8 01:30   13709 GOES16  
C4.0 01:56   13703 GOES16  
C3.9 02:59   13697 GOES16  
C5.9 03:07 behind northwest limb 13695 GOES16 simultaneous flare in AR 13697
C6.8 03:48   13698 GOES16  
C5.0 05:15 behind northwest limb 13695 GOES16 incorrectly attributed to AR 13697 by SWPC
C4.6 06:53   13697 GOES16  
C7.8 07:18 S21W53 13697 GOES16  
C9.0 08:48   13709 GOES16  
M4.0 09:13 S10E84 13709 GOES16  
C4.0 10:14   13709 GOES16  
C5.0 11:04 behind northwest limb 13695 GOES16  
C7.0 12:19 behind northwest limb 13695 GOES16  
C6.0 13:19   13697 GOES16  
C7.8 16:00   13697 GOES16  
M1.2 16:22 S20W50 13697 GOES16  
C5.7 17:34   13697 GOES16  
C5.6 17:52   13697 GOES16  
C5.7 18:31   13697 GOES16  
C7.0 19:05 S17W66 13697 GOES16  
C3.6 19:56   13697 GOES16  
C2.9 20:33   13697 GOES16  
C3.9 22:13   13697 GOES16  
C4.0 22:21   13697 GOES16  
C4.7 22:42   13697 GOES16  
C4.4 23:19   13697 GOES16  
C4.3 23:39   13707 GOES16  

Coronal mass ejections (CMEs)

June 5-7: No obviously Earth directed CME observed.
June 8: A partial halo CME was observed after the M9 flare in AR 13697 at 01:49 UT. The CME could reach Earth on June 10 and cause active to severe storm conditions.

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 northern hemisphere coronal hole (CH1224) rotated across the central meridian on June 4-6. A southern hemisphere negative polarity coronal hole (CH1225) could become Earth facing on June 10, however, is showing signs of decay.

Propagation

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

Forecast

The geomagnetic field is expected to be at quiet to active levels on June 8-10 due to effects from CH1224.

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
13697 2024.05.27
2024.05.28
19 36 18 S17W58 0320 DKC FKC beta-gamma-delta

location: S19W58

area: 0420

13698 2024.05.28
2024.05.30
8 9 6 N22W68 0130 DAI EAO

area: 0150

13701 2024.05.31
2024.06.01
4 3 2 S06W53 0050 DAO DAO

location: S06W55

13703 2024.05.31
2024.06.03
13 26 10 S08W37 0200 DAC DAI beta-gamma

location: S08W35

area: 0270

S9760 2024.06.01       N11W27            
13702 2024.06.01
2024.06.02
1 13 4 N17E03 0080 HSX CSO

area: 0170

location: N17E05

S9762 2024.06.01       S14W06            
13704 2024.06.02
2024.06.03
1 3 1 S18E08 0030 HRX CAO

 

13706 2024.06.03
2024.06.04
      S12W13         location: S12W21
S9769 2024.06.03   2   N09E18 0005   BXO  
S9770 2024.06.04       N15W23            
S9771 2024.06.04   2   N36E04 0004   BXO  
S9772 2024.06.04       S05E01            
S9774 2024.06.05       S27E26            
13707 2024.06.05
2024.06.06
10 20 9 S15E46 0080 DAI DAI area: 0140

location: S15E47

13708 2024.06.05
2024.06.06
1 4 2 S23E59 0060 HSX CAO area: 0080
S9777 2024.06.06       S17W29          
S9778 2024.06.06   1   N26E29 0001   AXX  
13709 2024.06.06
2024.06.07
3 10 7 S10E74 0080 CAI CKO area: 0410

location: S10E67

S9780 2024.06.07   2 1 S21W78 0010   AXX    
S9781 2024.06.07   4   S25E48 0007   BXO    
S9782 2024.06.07   5 2 S08E58 0010   BXO    
S9783 2024.06.07   4 2 S08E81 0040   CRO   beta-delta?
Total spot count: 60 144 64  
Sunspot number: 150 304 184  (total spot count + 10 * number of spotted regions)
Weighted SN: 108 202 122  (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): 165 167 147  

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
2024.05 187.8 191.9 171.7 (SC25 peak) (126.7 projected, +1.1) 23.6
(current
SC25 peak)
2024.06 188.1 (1)   43.5 (2A) / 186.3 (2B) / 183.9 (2C) (125.9 projected, -0.8) (9.2)
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.