Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 9, 2024 at 06:05 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 quiet to unsettled levels on July 8. The high latitude magnetometer at Andenes recorded quiet to active 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 168.5 - increasing 3.6 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 163.30. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 163.32 on January 7, 2024). The Potsdam WDC planetary A index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 9.0). Three hour interval K indices: 22233222 (planetary), ******** (Boulder), 34133333 (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 14 active regions using 2K resolution (SN: 282) and in 12 active regions using 1K resolution (SN: 190) SDO/HMI images.

Region 13734 [N08W55] decayed slowly and quietly.
Region 13736 [S19W01] was mostly quiet and stable.
Region 13738 [S09E27] gained area and spots. A major flare is possible, even if the spot group currently only has mild polarity intermixing.
Region 13739 [N04W47] was quiet and stable.
Region 13740 [S18W31] produced a few C flares and lost the magnetic delta configuration.
Region 13741 [N09E49] was quiet and stable.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9870 [S21W13] was quiet and stable.
S9874 [S24E81] appeared to have only small leader spots, however, towards the end of the day a large trailing spot rotated into view. M flares are possible.
S9875 [S17E14] was quiet and stasble.
S9877 [S25W03] was quiet and stable.
New region S9879 [S08E78] rotated into view with small spots.
New region S9880 [N09E00] emerged with tiny spots.
New region S9881 [S19E82] rotated into view with small spots.
New region S9882 [S11W01] emerged with tiny spots.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.7 01:23   13733 GOES16  
C5.6 01:59 southeast limb S9879 GOES16 nearly simultaneous flares in AR S9874 and 13738
C5.3 02:51   13738 GOES16  
C4.6 02:57   13733 GOES16  
C4.3 03:55 S14E42 13738 GOES16  
C5.3 04:41   S9874 GOES16  
C5.5 05:35   S9874 GOES16  
C5.7 05:42   S9874 GOES16  
C4.4 07:59   13733 GOES16 simultaneous flare in AR S9874
C6.4 08:45   13738 GOES16  
C3.8 09:09 behind northeast limb   GOES16  
C2.7 10:09   13738 GOES16  
C2.7 10:20   13738 GOES16  
C4.2 11:13   13740 GOES16  
C4.2 11:33   13740 GOES16  
C2.7 12:14   S9874 GOES16  
M1.1 12:41 S23E78 S9874 GOES16  
C4.4 13:03   13740 GOES16 simultaneous flare in AR S9877
C3.9 14:15 S10E32 13738 GOES16  
C4.6 14:44 S16W26 13740 GOES16  
C4.2 15:06   S9881 GOES16  
C2.9 17:11   S9879 GOES16  
C3.0 17:22   S9881 GOES16  
C2.9 17:33   13738 GOES16  
C7.6 17:50   S9881 GOES16  
C3.8 18:18   S9874 GOES16  
C4.9 18:51 S20E04 13736 GOES16  
C3.2 19:41 S09E29 13738 GOES16  
C2.1 23:15 behind northeast limb   GOES16  

Coronal mass ejections (CMEs)

July 6-8: 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) was in an Earth facing position on July 6-7. A positive polarity northern hemisphere coronal hole (CH1231) will likely rotate across the central meridian on July 10-11.

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 to unsettled on July 9. Quiet to active conditions are possible on July 10-11 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
13734 2024.06.28
2024.06.29
1 3 1 N09W59 0010 AXX BXO location: N08W55
13735 2024.06.29
2024.06.29
      N17W46          
13736 2024.07.02
2024.07.03
3 13 5 S18W00 0110 CSO CAO location: S19W01

area: 0130

S9858 2024.07.02       S23W53            
S9859 2024.07.03       S27E02            
13739 2024.07.04
2024.07.06
  4 1 N04W41 0010   CRO location: N04W47
13738 2024.07.04
2024.07.05
32 65 43 S08E30 0330 EKC FKI beta-gamma

area: 0750

location: S09E27

S9866 2024.07.04       N24W49            
13740 2024.07.04
2024.07.06
3 7 2 S17W32 0010 BXO CRO

location: S18W31

S9868 2024.07.05       N32W41            
S9869 2024.07.05       N27W27            
S9870 2024.07.06   6   S20W13 0020   AXX  
S9872 2024.07.06       S07E11            
13741 2024.07.07
2024.07.07
1 5 2 N09E48 0010 HRX CRO area: 0020

location: S09E49

S9874 2024.07.07   5 3 S24E81 0290   EHO  
S9875 2024.07.07   5 2 S17E14 0010   AXX  
S9876 2024.07.07       N21W19          
S9877 2024.07.07   10 4 S25W03 0025   BXO  
S9879 2024.07.08   6 4 S08E78 0040   DRO    
S9880 2024.07.08   2   N09E00 0003   BXO    
S9881 2024.07.08   6 2 S19E82 0020   BXO    
S9882 2024.07.08   5 1 S11W01 0010   BXO    
Total spot count: 40 142 70  
Sunspot number: 90 282 190  (total spot count + 10 * number of spotted regions)
Weighted SN: 58 179 107  (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): 99 155 152  

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
2024.07 168.2 (1)   36.5 (2A) / 141.4 (2B) / 157.7 (2C) (134.8 projected, -0.1) (5.9)
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.