Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 23, 2024 at 06:25 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 (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 (June 17, 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 levels on June 22. The high latitude magnetometer at Andenes recorded quiet to unsettled levels. The above 10 MeV proton flux was at  background levels at the end of the day. A weak disturbance related to CH1228 appears to be in progress as this report is being prepared.

Solar flux density measured at 20h UT on 2.8 GHz was 195.7 - increasing 40.1 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 162.58. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 162.58 on December 23, 2023). The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.0). Three hour interval K indices: 20000111 (planetary), 20112311 (Boulder), 31101120 (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 13 active regions using 2K resolution (SN: 263) and in 12 active regions using 1K resolution (SN: 201) SDO/HMI images.

Region 13712 [S26W75] displayed no major changes and produced several C flares.
Region 13713 [S14W63] still has a significant magnetic delta in the leading penumbra, however, the region lost both spots and area. The region produced only a few C flares, however, a major flare is still possible.
Region 13716 [N09W71] decayed slowly and is no longer a compact spot group. The region produced several C flares and the largest M flare of the day.
Region 13718 [N17W23] was quiet and stable.
Region 13719 [S14E26] was mostly quiet and stable.
Region 13720 [S06E37] has many small spots and a small magnetic delta configuration. Several C and one M class flares were recorded.
Region 13721 [N25E64] was quiet and stable.
Region 13722 [S12E63] was mostly quiet and stable.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9806 [S10W46] was quiet and stable.
S9815 [N15E35] was quiet and stable.
S9817 [N18E49] gained a few tiny spots.
New region S9822 [S19E80] rotated into view with several spots and could produce another M flare.
New region S9823 [S04E79] rotated into view with small spots.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C7.3 00:25   13716 GOES16 simultaneous flare in AR 13620
C6.9 01:33   13712 GOES16  
C7.5 01:51   13716 GOES16  
C5.3 02:46   13716 GOES16 simultaneous flare in AR 13713
C5.7 02:58   13720 GOES16  
C6.4 03:03   13716 GOES16  
C6.0 03:55   13712 GOES16  
C5.7 04:07   S9822 GOES16  
M1.2 04:38 southeast limb S9822 GOES16  
C4.5 05:57   13722 GOES16  
C3.8 06:12   13720 GOES16  
C5.1 06:29   S9808 GOES16  
C3.3 07:30   S9822 GOES16  
C3.4 08:18   13713 GOES16  
C3.2 08:35   S9822 GOES16 simultaneous flare in AR 13712
M2.8/1F 08:55   13716 GOES16  
C8.0 10:29   13712 GOES16  
C7.8 10:35   13720 GOES16  
C7.4 10:45   13720 GOES16  
M1.0 11:06   13720 GOES16 simultaneous flare in AR S9822
C6.0 12:13   13712 GOES16  
C5.0 12:40   13712 GOES16  
C3.5 13:22   13720 GOES16  
C3.1 14:06   13720 GOES16  
C3.8 14:51   13720 GOES16  
C4.9 14:58   13716 GOES16  
C5.2 16:22   13720 GOES16  
C3.4 17:17   13712 GOES16  
C3.1 17:35   13712 GOES16  
C4.5 17:47   S9822 GOES16  
C5.9 18:00   13712 GOES16  
C2.7 19:30   13720 GOES16  
C8.7/1F 19:49   13720 GOES16  
C8.6 19:55   13712 GOES16  
C3.5 20:43   13722 GOES16  
C3.9 21:13   13712 GOES16  
C3.9 21:17   13712 GOES16  
C3.0 21:46   13720 GOES16  
C3.1 22:07   S9822 GOES16  
C3.5 22:14   13713 GOES16  
C4.0 22:26   13720 GOES16  
C3.2 22:36   13720 GOES16  
C3.1 23:03   13720 GOES16 simultaneous flare in AR 13712
C2.9 23:45   S9822 GOES16  

Coronal mass ejections (CMEs)

June 20-22: No obviously Earth directed CMEs 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 negative polarity northern hemisphere coronal hole (CH1228) rotated across the central meridian on June 18.

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 23 due to weak effects from CH1228. Quiet conditions are likely on June 24-25.

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
13712 2024.06.11
2024.06.12
9 12 8 S25W77 0720 EKC FKC

beta-gamma-delta

area: 1210

location: S26W75

13713 2024.06.11
2024.06.12
24 34 17 S14W65 0910 EKC EKC beta-gamma-delta

location: S14W63

area: 1050

13716 2024.06.12 10 12 8 N10W72 0450 EKC EKC beta-gamma-delta

area: 0580

location: N09W71

S9802 2024.06.15       S32W39            
S9804 2024.06.16       N17W56            
S9805 2024.06.16       S11W11            
S9806 2024.06.17   1 1 S10W46 0003   AXX  
13718 2024.06.18
2024.06.19
  2   N12W27 0004   AXX location: N17W23
S9812 2024.06.18       N27W29            
13719 2024.06.19
2024.06.19
10 19 12 S14E24 0150 DSO EHI

area: 0350

location: S14E26

13720 2024.06.19
2024.06.19
13 32 22 S05E36 0120 DAI DRI

beta-delta

area: 0180

location: S06E37

S9815 2024.06.19   4 2 N15E35 0008   BXO  
S9816 2024.06.20       S17W17            
S9817 2024.06.20   6 3 N18E49 0010   BXO  
13721 2024.06.21
2024.06.21
1 1 1 N26E59 0090 HSX HSX area: 0170

location: S25E64

13722 2024.06.21
2024.06.21
2 2 2 S13E62 0110 DSO HSX area: 0270

location: S12E63

S9820 2024.06.21       N04W07          
S9821 2024.06.21       S08W45          
S9822 2024.06.22   5 3 S19E80 0150   EAO    
S9823 2024.06.22   3 2 S04E79 0020   ERO    
Total spot count: 69 133 81  
Sunspot number: 139 263 201  (total spot count + 10 * number of spotted regions)
Weighted SN: 119 194 142  (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): 153 145 161  

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)
2024.06 183.5 (1)   113.5 (2A) / 154.8 (2B) / 156.0 (2C) (125.9 projected, -0.8) (8.4)
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.