Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 8, 2024 at 03:35 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 (August 4, 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 (August 1, 2024) Noon SDO sunspot count 1K image / 4K (*)
  Solar cycles 1-24 (August 1, 2020) POES auroral activity level [October 2009 - December 2012]
  Comparison of cycles 21-25 (August 1, 2024) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (August 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 August 7. 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 303.2 - increasing 89.6 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 166.67. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 166.67 on February 7, 2024). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 5.6). Three hour interval K indices: 12122112 (planetary), 12223413 (Boulder), 22032114 (Andenes).

The background x-ray flux is at the class C4 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 16 active regions using 2K resolution (SN: 574) and in 15 active regions using 1K resolution (SN: 353) SDO/HMI images.

AR 13769 [N23W79] was quiet and stable.
AR 13772 [S24W49] decayed further and has only rudimentary penumbra on the trailing spots.
AR 13774 [S07W24] decayed in the trailing spot section, has many small spots and polarity intermixing. Further M class flaring is likely.
AR 13775 [N18W33] decayed slowly and was mostly quiet.
AR 13777 [S09W07] gained area. The trailing spot section could be developing into a separate spot group. M flares are likely.
AR 13780 [S09E33] currently has no magnetic delta configurations and was mostly quiet. A major flare is possible
AR 13781 [N14E39] still has a magnetic delta configuration. Further M class flares are likely.
New AR 13782 [N02E66] rotated into view on August 6 and was numbered by SWPC the next day.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9984 [S14W22] decayed slowly and quietly.
S9999 [N16W00] was quiet and stable.
New region S10000 [N10E31] emerged with several spots.
New region S10001 [N24W36] emerged with spots before noon, then decayed slowly.
New region S10002 [N12W29] emerged with tiny spots.
New region S10003 [N16E85] rotated into view with a large spot.
New region S10004 [N05W23] emerged with spots before noon, then decayed slowly.
New region S10005 [S22E48] was observed with tiny spots in an old plage area.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C5.2 00:09   13780 GOES16  
C5.6 00:17 N06W79 (SDO/AIA) S9977 GOES16  
C4.4 00:52   13777 GOES16  
C4.4 01:46   S9977 GOES16  
C8.5 02:01 N05W75 S9977 GOES16  
C5.6 02:18   14774 GOES16  
M1.8/1N 02:30 S08W18 13774 GOES16 moderate type II radio sweep
C9.5 02:53   13781 GOES16  
C5.7 03:11   13774 GOES16  
C7.9 03:25 S02W13 13774 GOES16  
C3.9 04:25   13780 GOES16  
M1.1/1N 04:57 N13E53 13781 GOES16  
C5.6 05:37   13781 GOES16  
C4.8 06:07   13777 GOES16  
C4.7 06:37   13774 GOES16  
C4.9 06:48     GOES16  
C3.7 07:48   13777 GOES16  
C3.7 07:56   13781 GOES16  
C3.5 08:18   13780 GOES16  
C3.9 08:38   13777 GOES16  
C3.7 09:56   13777 GOES16  
C4.1 10:11   13772 GOES16  
C5.4 10:39 N15E51 13781 GOES16  
C3.1 11:03   13777 GOES16  
C4.5 12:25 S13E39 13780 GOES16 simultaneous flare in AR 13774
C7.2 13:38   13780 GOES16  
M4.5 13:50   13774 GOES16 moderate type II radio sweep, halo CME
C7.4 15:05 S22W37 13772 GOES16 simultaneous flare in AR 13782
C6.4 15:12   13780 GOES16  
C6.2 15:25   13780 GOES16  
C4.8 17:20   13780 GOES16  
M5.0/2B 18:54 S07W07 13777 GOES16 moderate type II radio sweep
M1.9 19:22   13774 GOES16  
C7.4 20:28   13774 GOES16  
C4.4 22:45   13781 GOES16  

Coronal mass ejections (CMEs)

August 5-6: No obviously Earth directed CMEs were observed.
August 7: A faint full halo CME was observed after an M4.5 flare peaking at 13:50 UT in AR 13774. The CME could reach Earth early on August 10.

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 small northern hemisphere positive polarity coronal hole (CH1234) rotated across the central meridian on August 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 at quiet levels on August 8-9. Quiet to minor storm conditions are possible on August 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
13769 2024.07.25
2024.07.26
2 1 1 N23W83 0090 HSX HSX location: N23W79
13772 2024.07.29
2024.07.30
8 26 15 S25W45 0260 EKO EKO

area: 0310

location: S24W49

13775 2024.07.30
2024.07.31
8 20 8 N18W34 0040 CSO DAO beta-gamma

location: N18W33

area: 0060

13774 2024.07.30 39 114 53 S07W24 0420 EKC EHC beta-gamma

area: 0650

13776 2024.07.31
2024.08.01
      N09W49        

location: N08W51

13777 2024.08.01
2024.08.02
17 57 31 S09W06 0310 EKI EKI location: S09W07

area: 0630

S9984 2024.08.02   7 3 S14W22 0015   BXO see AR 13779 which SWPC relocated to this spot group on 2024.08.05
S9985 2024.08.02       N22W22            
S9986 2024.08.03       S28E03            
S9987 2024.08.03       N04W50            
13780 2024.08.03
2024.08.04
67 117 60 S09E27 1110 FKC FKC beta-gamma

location: S09E33

area: 1510

13779 2024.08.03
2024.08.04
1     S13W21 0005 AXX       see AR S9984
S9992 2024.08.03       N18E20            
13781 2024.08.04
2024.08.05
7 18 6 N13E36 0140 DSO DSC beta-delta

location: N14E39

area: 0300

S9995 2024.08.05       N07W05            
S9996 2024.08.05       N39W15            
13782 2024.08.06
2024.08.07
3 14 5 N02E65 0320 EAO EAO location: N02E66

area: 0380

S9999 2024.08.06   8 3 N16W00 0015   AXX  
S10000 2024.08.07   18 11 N10E31 0070   DRI    
S10001 2024.08.07   1   N24W36 0002   AXX    
S10002 2024.08.07   6 3 N12W29 0025   CRO    
S10003 2024.08.07   1 1 N16E85 0600   HHX    
S10004 2024.08.07   2 1 N05W23 0006   AXX    
S10005 2024.08.07   4 2 S22E48 0008   AXX    
Total spot count: 152 414 203  
Sunspot number: 242 574 353  (total spot count + 10 * number of spotted regions)
Weighted SN: 212 490 279  (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): 266 316 282  

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
2022.11 123.4 120.7 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  176.4 182.2 160.0 124.6 (-0.7) 8.15
2023.08  153.7 157.6 114.8 124.3 (-0.3) 7.19
2023.09  154.4 156.0 134.2 124.0 (-0.3) 14.26
2023.10  142.8 141.9 99.4 124.8 (+0.8) 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
2024.01 164.6 159.3 126.0 131.1 (+1.7) 5.46
2024.02 172.5 168.3 123.0 (134.7 projected, +3.6) 5.31
2024.03 154.4 152.9 103.7 (138.1 projected, +3.4) 11.03
2024.04 161.3 162.6 136.5 (141.7 projected, +3.6) 9.69
2024.05 187.7
(cycle peak)
191.9 171.7 (146.2 projected, +4.5) 23.56
(SC25 peak)
2024.06 184.3 190.2 164.2 (149.9 projected, +3.7) 10.24
2024.07 196.9 203.0 196.5  (SC25 peak) (151.4 projected, +1.5) 7.1
2024.08  255.3 (1)   49.8 (2A) / 220.6 (2B) / 238.8 (2C) (151.3 projected, -0.1) (14.8)
2024.09       (151.2 projected, -0.1)  
2024.10       (151.1 projected, -0.1)  
2024.11       (149.1 projected, -2.0)  
2024.12       (144.8 projected, -4.3)  
2025.01       (138.6 projected, -6.2)  
2025.02       (133.7 projected, -4.9)  

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 August 2, 2024

Sunspot counts in July 2024 were the highest we've seen during solar cycle 25. With three consecutive months of high sunspot counts the projected peak for the smoothed ISN (365 days smoothing) has increased significantly to near 150. The month of the peak is currently likely to occur sometime between June and October 2024.

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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.