Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 7, 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 (July 3, 2024)
Solar cycle Solar cycles 23-25 (July 1, 2024) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (July 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 (July 1, 2024) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (July 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 very quiet levels on July 6. 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.

Solar flux density measured at 20h UT on 2.8 GHz was 166.0 - decreasing 14.9 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 163.29. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 163.29 on January 6, 2024). The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 2.6). Three hour interval K indices: 11100101 (planetary), ******** (Boulder), 21010113 (Andenes).

The background x-ray flux is at the class C2 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 15 active regions using 2K resolution (SN: 249) and in 9 active regions using 1K resolution (SN: 151) SDO/HMI images.

Region 13727 [S18W85] rotated partly out of view.
Region 13729 [S04W72] decayed and was mostly quiet.
Region 13733 [N04W67] was mostly quiet and stable.
Region 13734 [N08W29] decayed slowly and quietly.
Region 13735 [N17W17] decayed slowly and quietly.
Region 13736 [S19E25] was mostly quiet and stable.
Region 13738 [S08E55] developed slowly and produced many C flares and a minor M class flare.
New region 13739 [N03W15] emerged on July 4 and was numbered by SWPC 2 days later.
New region 13740 [S18W03] emerged on July 4 and was numbered by SWPC 2 days later. The region has minor polarity intermixing as this was originally two very closely spaced spot groups.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9866 [N24W23] was quiet and stable.
New region S9870 [S08E10] was observed with tiny spots in an old plage area.
New region S9871 [N00W43] emerged with a tiny spot at the equator.
New region S9872 [S07E37] was observed with a tiny spot in an old plage area.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.2 00:48   13729 GOES16  
C2.2 01:26   13736 GOES16  
C2.0 04:00   13738 GOES16  
C2.4 06:04 behind southwest limb   GOES16  
C2.7 06:50   13733 GOES16  
C3.8 08:51 behind southeast limb   GOES16  
C6.7 09:45 behind southeast limb   GOES16  
C6.1 10:21   13729 GOES16  
C5.3 11:19   13733 GOES16  
C3.0 12:19 behind southwest limb   GOES16  
C3.6 13:10 S08E64 13738 GOES16 simultaneous flare in AR 13729
C2.4 13:34   13733 GOES16  
C2.5 15:27   13733 GOES16 simultaneous flare in AR 13738
C2.1 16:56   13738 GOES16  
C2.1 17:07   13738 GOES16  
C2.2 17:18   13738 GOES16  
C2.7 17:26   13738 GOES16  
C2.7 18:39   13733 GOES16  
C3.8 18:58 S09E59 13738 GOES16  
C3.6 20:03   13738 GOES16  
C5.1 21:34 behind southeast limb   GOES16 simultaneous flare in AR 13738
C4.2 22_10   13738 GOES16 simultaneous flare in AR 13738
M1.0 23:15   13738 GOES16  
C9.4 23:42 behind southeast limb   GOES16  

Coronal mass ejections (CMEs)

July 4-6: 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 southern hemisphere coronal hole (CH1230) could rotate into an Earth facing position on July 6-7.

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.

Forecast

The geomagnetic field is expected to be quiet on July 7-9. Quiet to active conditions are possible on July 10 due to effects from CH1230.

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
13727 2024.06.24
2024.06.25
1 1   S18W85 0030 HAX HAX  
13729 2024.06.25
2024.06.26
2 8 4 S05W72 0080 HAX CAO

 

13731 2024.06.26
2024.06.28
      S16W62          

location: S17W53

13733 2024.06.28
2024.06.29
10 13 8 N05W68 0300 DKI DKI

location: N04W67

area: 0400

13734 2024.06.28
2024.06.29
1 8 3 N09W31 0010 AXX CRO location: N08W29

area: 0020

13735 2024.06.29
2024.06.29
1 5 1 N17W17 0020 HRX CRO  
S9847 2024.06.29       S13W46            
S9851 2024.06.30       S40W48            
S9854 2024.07.01       N23W46            
S9856 2024.07.01       S28W57            
13736 2024.07.02
2024.07.03
5 14 5 S19E27 0120 CSO DSO location: S19E25

area: 0180

S9858 2024.07.02       S23W27          
S9859 2024.07.03       S27E28            
S9860 2024.07.03       S04W49            
S9861 2024.07.04       N10W35            
13739 2024.07.04
2024.07.06
3 17 8 N03W17 0010 BXO BXO location: N03W15

area: 0050

13738 2024.07.04
2024.07.05
15 35 25 S09E58 0290 EKC EAC beta-gamma

area: 0500

location: S08E55

S9866 2024.07.04   3 1 N24W23 0006   AXX  
13740 2024.07.04
2024.07.06
4 11 6 S20W03 0010 BXO DRI beta-gamma

location: S18W03

S9868 2024.07.05       N32W15          
S9869 2024.07.05       N27W01          
S9870 2024.07.06   2   S08E10 0003   AXX    
S9871 2024.07.06   1   N00W43 0002   AXX    
S9872 2024.07.06   1   S07E37 0003   AXX    
Total spot count: 42 119 61  
Sunspot number: 132 249 151  (total spot count + 10 * number of spotted regions)
Weighted SN: 80 158 105  (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): 145 137 121  

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
2023.12 151.1 146.4 114.2 129.4 (+1.6) 9.60
2024.01 164.6 159.3 123.0 (128.9 projected, -0.5) 5.46
2024.02 172.5 168.3 124.7 (129.4 projected, +0.5) 5.31
2024.03 154.4 152.9 104.9 (130.3 projected, +0.9) 11.03
2024.04 161.3 162.6 136.5 (131.0 projected, +0.7) 9.69
2024.05 187.7
(cycle peak)
191.9 171.7 (SC25 peak) (133.2 projected, +2.2) 23.56
(SC25 peak)
2024.06 184.3 190.2 164.2 (134.9 projected, +1.7) 10.24
2024.07 167.7 (1)   29.7 (2A) / 153.7 (2B) / 158.3 (2C) (134.8 projected, -0.1) (5.3)
2024.08       (134.3 projected, -0.5)  
2024.09       (134.4 projected, +0.1)  
2024.10       (134.3 projected, -0.1)  
2024.11       (132.3 projected, -2.0)  
2024.12       (128.0 projected, -4.3)  
2025.01       (124.0 projected, -4.0)  

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 July 5, 2024

Sunspot counts in June 2024 were almost at the level of May 2024 and the second highest month during solar cycle 25. Looking at the projected activity for the remainder of this year, solar max now looks likely to occur between May and October 2024. A big decrease in sunspot formation in July 2024 and over the next months could change the projected maximum to earlier in 2024 or even to December 2023.

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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.