Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 8, 2024 at 07:00 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 7. The high latitude magnetometer at Andenes recorded quiet to minor storm 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 171.3 - decreasing 6.5 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 163.32. 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 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.5). Three hour interval K indices: 22102123 (planetary), ******** (Boulder), 41112125 (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: 269) and in 11 active regions using 1K resolution (SN: 164) SDO/HMI images.

Region 13733 [N05W79] decayed slowly and was mostly quiet.
Region 13734 [N08W42] decayed slowly and quietly.
Region 13735 [N17W30] decayed slowly and quietly.
Region 13736 [S19E11] was quiet and stable.
Region 13738 [S09E41] developed further and was unstable. Frequent C class flaring was observed and a minor M class flare is possible.
Region 13739 [N04W30] decayed slowly and quietly.
Region 13740 [S18W17] was mostly quiet. The region has a small magnetic delta configuration in the central part.
New region 13741 [N09E63] emerged with small spots.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9870 [S15E01] was quiet and stable.
New region S9874 [S23E82] rotated partly into view. This spot group was quiet active late in the day and produced several M flares. Another 2 spot groups just behind the southeast limb were also active late in the day
New region S9875 [S17E28] was observed with tiny spots in an old plage area.
New region S9876 [N21W06] emerged with a tiny spot.
New region S9877 [S25E17] emerged with tiny spots to the south of AR 13736.
New region S9878 [S17W62] emerged with tiny spots.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C4.1 01:10   13729 GOES16  
C7.2 01:59   13729 GOES16  
C3.2 02:14   13738 GOES16  
C3.8 02:29   13738 GOES16  
C4.9 02:48   13738 GOES16  
C3.9 04:53   13741 GOES16  
C4.8 05:22   13738 GOES16  
C8.2 05:46 southeast limb S9874 GOES16 incorrectly attributed to AR 13738 by SWPC
C6.0 06:17   13738 GOES16  
C4.7 07:05   13738 GOES16  
C4.1 07:19   13738 GOES16  
C4.0 07:26   13738 GOES16  
C4.3 07:37   13738 GOES16  
C4.4 07:53   13738 GOES16  
C3.6 08:36   13738 GOES16  
C3.6 08:43   13733 GOES16  
C4.1 09:39   13733 GOES16  
C3.5 10:40   13738 GOES16 simultaneous flare in AR 13733
C4.1 11:07   13738 GOES16  
C3.2 11:41   13729 GOES16  
C3.5 12:14   13733 GOES16  
C2.9 12:43   13738 GOES16  
C3.4 13:07   13738 GOES16  
C3.9 13:26   13738 GOES16  
C3.1 13:54 southeast limb S9874 GOES16  
C4.5 15:07   13738 GOES16 simultaneous flare in AR 13733
C4.5 15:17 behind southeast limb   GOES16  
C4.5 15:50   13738 GOES16  
C3.8 16:34   13733 GOES16  
C3.5 16:46   13740 GOES16  
C3.2 17:13   13733 GOES16  
C5.4 17:49 behind southeast limb   GOES16 incorrectly attributed to smaller, simultaneous flare in AR 13738 by SWPC
M1.0 19:55 southeast limb S9874 GOES16  
C6.5 20:14   13738 GOES16  
M1.3 21:27 behind southeast limb   GOES16  
M1.4 21:59 southeast limb S9874 GOES16  
M2.4 22:30 southeast limb S9874 GOES16  
M1.0 23:23   13738 GOES16  
C6.3 23:47   13738 GOES16  

Coronal mass ejections (CMEs)

July 5-7: 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 8-9. 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
13729 2024.06.25
2024.06.26
3     S05W84 0040 CSO    

rotated out of view

13731 2024.06.26
2024.06.28
      S16W76          

location: S17W66

13733 2024.06.28
2024.06.29
3 4 2 N05W81 0150 DSO CKO

location: N05W79

area: 0300

13734 2024.06.28
2024.06.29
1 12 3 N09W45 0010 AXX CRO location: N08W42

area: 0020

13735 2024.06.29
2024.06.29
1 4 2 N17W31 0010 AXX BXO  
S9847 2024.06.29       S13W59            
S9854 2024.07.01       N23W59            
13736 2024.07.02
2024.07.03
2 19 4 S19E16 0120 CSO CSO location: S19E11

area: 0160

S9858 2024.07.02       S23W40            
S9859 2024.07.03       S27E15            
S9861 2024.07.04       N10W48            
13739 2024.07.04
2024.07.06
1 3 1 N04W26 0010 AXX BXO location: N04W30

area: 0007

13738 2024.07.04
2024.07.05
15 57 34 S09E44 0280 EKC EAC beta-gamma

area: 0640

location: S09E41

S9866 2024.07.04       N24W36          
13740 2024.07.04
2024.07.06
2 7 4 S18W18 0020 CRO DRI beta-delta

location: S18W17

S9868 2024.07.05       N32W28            
S9869 2024.07.05       N27W14            
S9870 2024.07.06   9 1 S15E01 0020   AXX  
S9871 2024.07.06       N00W56          
S9872 2024.07.06       S07E24          
13741 2024.07.07
2024.07.07
1 3 1 N09E63 0010 AXX HRX   was AR S9843

area: 0020

S9874 2024.07.07   1 1 S23E82 0020   HRX    
S9875 2024.07.07   3   S17E28 0004   AXX    
S9876 2024.07.07   1   N21W06 0002   AXX    
S9877 2024.07.07   4 1 S26E17 0008   BXO    
S9878 2024.07.07   2   S17W62 0002   BXO    
Total spot count: 29 129 54  
Sunspot number: 119 269 164  (total spot count + 10 * number of spotted regions)
Weighted SN: 57 161 86  (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): 131 148 131  

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)   33.6 (2A) / 148.7 (2B) / 157.8 (2C) (134.8 projected, -0.1) (5.5)
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.