Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 7, 2024 at 05:40 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 6. 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 270.0 - increasing 91.8 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 166.26. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 166.26 on February 5, 2024). The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.5). Three hour interval K indices: 21200112 (planetary), 32312312 (Boulder), 42111222 (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 12 active regions using 2K resolution (SN: 491) and in 11 active regions using 1K resolution (SN: 317) SDO/HMI images.

AR 13769 [N23W66] was quiet and stable.
AR 13772 [S24W35] decayed significantly in the trailing spot section and was mostly quiet. A small magnetic delta configuration formed in a small penumbra southeast of the largest penumbra.
AR 13774 [S07W10] gained many spots and could produce a major flare.
AR 13775 [N18W19] gained tiny spots, lost area and was mostly quiet.
AR 13776 [N08W38] was quiet and stable.
AR 13777 [S08E06] developed significantly and could produce a major flare.
AR 13780 [S09E47] displayed no major changes and remains a compact and complex spot group with X class flare potential.
AR 13781 [N14E53] redeveloped a magnetic delta configuration and could produce M flares.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9977 [N06W78] decayed slowly and produced several flares.
S9984 [S14W08] decayed slowly and quietly.
New region S9998 [N03E78] rotated into view with a large spot.
New region S9999 [N20E18] was observed with tiny spots in an old plage area.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.4 00:13   13780 GOES16  
C4.4 00:57   13775 GOES16  
C7.8 01:13 N17W07 13775 GOES16  
C4.7 01:43   13774 GOES16  
M1.1 03:03   13781 GOES16  
C3.6 03:37   13780 GOES16  
C3.9 04:18   13781 GOES16  
C4.2 06:17 S08E47 13780 GOES16  
C4.9 07:08   13781 GOES16  
C3.8 07:37   13781 GOES16  
C3.5 07:55   13781 GOES16  
C4.8 09:39   13774 GOES16  
C8.1 11:35 S12W02 (SDO/AIA) 13774 GOES16 SWPC reports a location way off - S03W02
C8.2 11:40 S06W05 (SDO/AIA) 13774 GOES16  
C6.8 14:19 S05W02 13774 GOES16  
C4.8 14:46   13780 GOES16  
C3.8 15:07 behind southwest limb   GOES16  
C4.3 15:21   13777 GOES16  
C5.8 16:15 S11E47 13780 GOES16  
C3.8 17:57   13780 GOES16  
C5.3 18:26   13774 GOES16  
C4.4 18:43   13772 GOES16  
C3.5 19:51 behind southwest limb   GOES16  
C4.4 20:00 behind southwest limb   GOES16  
C3.7 20:07   13774 GOES16  
C4.8 20:45   S9977 GOES16  
C4.2 21:14   13777 GOES16  
C4.0 22:24   13780 GOES16  

Coronal mass ejections (CMEs)

August 4-6: No obviously Earth directed CMEs were 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 small northern hemisphere positive polarity coronal hole (CH1234) will likely rotate 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 6-9. Quiet to unsettled conditions are possible on August 10-11 due to weak effects from CH1234.

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
1 4 3 N23W69 0100 HSX HSX location: N23W66
13772 2024.07.29
2024.07.30
12 34 17 S25W34 0320 EKO EKO beta-delta

area: 0410

location: S24W35

13775 2024.07.30
2024.07.31
6 27 13 N18W21 0040 CSO DAO beta-gamma

location: N18W19

area: 0070

13774 2024.07.30 46 106 57 S07W10 0440 EKC EHC beta-gamma

area: 0820

S9977 2024.07.30   3 2 N06W78 0020   HRX  
13776 2024.07.31
2024.08.01
  3   N09W35 0007   BXO

location: N08W38

13777 2024.08.01
2024.08.02
20 54 36 S09E07 0210 EAI DKC location: S08E06

area: 0570

S9983 2024.08.01       S19W54            
S9984 2024.08.02   6 4 S14W08 0030   DRO see AR 13779 which SWPC relocated to this spot group on 2024.08.05
S9985 2024.08.02       N22W08            
S9986 2024.08.03       S28E16            
S9987 2024.08.03       N04W37            
13780 2024.08.03
2024.08.04
44 114 63 S13E44 1220 FKC FKC beta-gamma-delta

location: S09E47

area: 1600

13779 2024.08.03
2024.08.04
8     S15W04 0030 CRO       SWPC has changed the location of the spot group to that of AR S9984
S9992 2024.08.03       N18E33            
13781 2024.08.04
2024.08.05
5 10 8 N13E53 0160 DAO DAC beta-gamma-delta

location: N14E53

area: 0300

S9995 2024.08.05       N07E08          
S9996 2024.08.05       N39W02          
S9998 2024.08.06   2 2 N03E78 0320   HKX    
S9999 2024.08.06   8 2 N20E18 0015   BXO    
Total spot count: 142 371 207  
Sunspot number: 222 491 317  (total spot count + 10 * number of spotted regions)
Weighted SN: 195 442 278  (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): 244 270 254  

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  247.4 (1)   42.0 (2A) / 217.0 (2B) / 234.4 (2C) (151.3 projected, -0.1) (16.3)
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.