Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 9, 2024 at 10:55 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 quiet to active levels on June 8 due to weakening CME effects. The high latitude magnetometer at Andenes recorded quiet to major storm levels. The above 10 MeV proton flux was at 81 pfu at the end of the day, having reached a peak of 1030 pfu at 08:00 UT following a major proton flare in AR 13697.

Solar flux density measured at 20h UT on 2.8 GHz was 190.4 - decreasing 31.4 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 161.79. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 161.79 on December 9, 2023). The Potsdam WDC planetary A index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 12.5). Three hour interval K indices: 43222322 (planetary), 43332422 (Boulder), 56233333 (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 14 active regions using 2K resolution (SN: 278) and in 13 active regions using 1K resolution (SN: 196) SDO/HMI images.

Region 13697 [S19W71] decayed slightly after producing many M flares early in the day. Another proton flare is possible while the region is rotating to and over the southwest limb.
Region 13698 [N22W83] decayed slowly and quietly.
Region 13701 [S05W69] decayed slowly and quietly.
Region 13702 [N17W09] decayed slowly and quietly.
Region 13703 [S07W48] decayed slowly and was mostly quiet.
Region 13704 [S17W04] decayed slowly and quietly.
Region 13707 [S15E31] decayed slowly and was mostly quiet.
Region 13708 [S22E47] was mostly quiet and stable.
Region 13709 [S09E54] was less active than on the previous day and is capable of producing further M flares.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9777 [S15W38] reemerged as new flux caused quick development of spots.
S9783 [S09E67] was mostly quiet and stable and appears to have a small magnetic delta configuration.
New region S9784 [S09W14] emerged with tiny spots.
New region S9785 [N14E78] rotated into view with a tiny spot.
New region S9786 [S23E12] was observed with tiny spots in an old plage area.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
M1.8 00:28 S13E47 13709 GOES16 simultaneous (and nearly equal magnitude) flare in AR 13707
M1.2 00:41   13697 GOES16  
M3.4/1F 00:51 S18W53 13697 GOES16  
M9.7 01:49 S18W53 13697 GOES16 partial halo CME, proton flare
strong type II and moderate type IV radio sweeps
M1.6 03:18   13709 GOES16  
C9.3 04:24   13709 GOES16  
C9.5 04:33   13697 GOES16  
C6.6 04:58   13709 GOES16  
M1.5 05:28 S21W61 13697 GOES16  
M1.2 08:44   13697 GOES16  
M1.2 08:58 S21W76 13697 GOES16  
C4.0 09:51   13709 GOES16  
C5.0 11:03   13697 GOES16  
C4.9 11:10   13697 GOES16  
C4.8 11:54   13697 GOES16  
C3.8 13:13   13703 GOES16  
C4.9 14:47   13709 GOES16  
C5.4 14:58   13697 GOES16  
C5.7 17:26   13697 GOES16  
C3.9 17:39   13697 GOES16  
C3.0 18:09   13697 GOES16  
C3.3 18:43   13697 GOES16  
C4.4 20:45   13697 GOES16  
C3.3 20:56   13697 GOES16  
M1.0 21:02   13703 GOES16  
C3.0 21:17   13697 GOES16  
C3.5 21:47   13697 GOES16  
C3.2 22:26   13697 GOES16  
C3.0 22:48   13697 GOES16  
C3.1 23:24   13697 GOES16  

Coronal mass ejections (CMEs)

June 6-7: 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 poor. Propagation on long distance northeast-southwest paths is poor to fair.

Forecast

The geomagnetic field is expected to be at quiet to unsettled levels on June 9 due to effects from CH1224 and quiet to severe storm levels on June 10-11 due to CME effects.

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 22 12 S17W72 0360 EKC EKC beta-gamma-delta

location: S19W71

area: 0510

13698 2024.05.28
2024.05.30
4 2 2 N22W82 0130 EAO EAO  
13701 2024.05.31
2024.06.01
3 3 2 S06W68 0040 CAO CRO

location: S05W69

13703 2024.05.31
2024.06.03
7 14 8 S08W52 0160 DAC DAI beta-gamma

location: S07W48

area: 0250

S9760 2024.06.01       N11W40            
13702 2024.06.01
2024.06.02
4 16 5 N16W08 0100 CSO DSO

area: 0160

location: N17W09

S9762 2024.06.01       S14W19            
13704 2024.06.02
2024.06.03
1 3 2 S18W06 0010 AXX HRX

location: S17W04

13706 2024.06.03
2024.06.04
      S12W27           location: S12W34
S9769 2024.06.03       N09E05          
S9770 2024.06.04       N15W36            
S9771 2024.06.04       N36W09          
S9772 2024.06.04       S05W12            
S9774 2024.06.05       S27E13            
13707 2024.06.05
2024.06.06
6 26 10 S15E32 0080 DAI EAI area: 0130

location: S15E31

13708 2024.06.05
2024.06.06
3 6 3 S23E45 0050 CAO CAO area: 0110

location: S22E47

S9777 2024.06.06   11 5 S15W38 0080   DAO    
S9778 2024.06.06       N26E16          
13709 2024.06.06
2024.06.07
6 19 8 S10E60 0080 CAI DKO area: 0510

location: S09E54

S9781 2024.06.07       S25E35          
S9782 2024.06.07       S08E45          
S9783 2024.06.07   8 4 S09E67 0050   DAO beta-delta?
S9784 2024.06.08   4 4 S09W14 0015   BXO    
S9785 2024.06.08   1 1 N14E78 0003   AXX    
S9786 2024.06.08   3   S23E12 0006   BXO    
Total spot count: 53 138 66  
Sunspot number: 143 278 196  (total spot count + 10 * number of spotted regions)
Weighted SN: 98 199 127  (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): 157 153 157  

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)
2024.06 188.4 (1)   48.2 (2A) / 180.9 (2B) / 182.2 (2C) (125.9 projected, -0.8) (9.6)
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.