Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 6, 2024 at 05:15 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 to unsettled levels on August 5. The high latitude magnetometer at Andenes recorded unsettled to active levels. The above 10 MeV proton flux was at 2.5 pfu at the end of the day.

Solar flux density measured at 20h UT on 2.8 GHz was 247.4 - increasing 78.9 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 165.98. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 165.98 on February 5, 2024). The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.5). Three hour interval K indices: 23322222 (planetary), 33332322 (Boulder), 33334333 (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: 381) and in 10 active regions using 1K resolution (SN: 240) SDO/HMI images.

AR 13769 [N22W53] was mostly quiet and stable.
AR 13772 [S24W21] decayed slowly and was mostly quiet. The spot group has only minor polarity intermixing.
AR 13774 [S07E03] developed in the trailing spot section and produced several C flares. M class flaring is likely.
AR 13775 [N18W05] decayed slowly and was mostly quiet.
AR 13776 [N09W19] was quiet and stable.
AR 13777 [S08E18] decayed slowly and was mostly quiet.
AR 13780 [S09E60] produced several flares including a major X1.1 event at 15:27 UT. Further X class flaring is possible.
New AR 13781 [N14E66] rotated into view on August 4 and was numbered by SWPC the next day. The region was much less active than during the previous days.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9977 [N05W62] developed as new flux emerged. Positive and negative polarity spots are poorly separated and a minor M class flare might be possible.
S9984 [S14E05] decayed slowly and quietly.
New region S9995 [N07E21] emerged before noon with a tiny spot.
New region S9996 [N39E11] emerged with a tiny spot.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C5.3 00:40   13780 GOES16  
C5.5 00:55   13780 GOES16  
C7.0 01:03   13780 GOES16  
C5.4 01:24   13774 GOES16  
C3.9 02:10   13774 GOES16  
C4.2 02:25   13780 GOES16  
M1.1 02:31 S11E63 13780 GOES16 moderate type II radio sweep
C3.5 03:33   13774 GOES16  
C3.7 04:23   13780 GOES16  
C3.6 04:42   13780 GOES16  
C4.0 05:02   13774 GOES16  
M6.1/1N 05:23 S11E62 13780 GOES16 strong type II radio sweep
C4.3 05:50   13774 GOES16  
C5.3 06:06   13765 GOES16  
C3.8 08:47   13774 GOES16  
C4.1 08:59   13780 GOES16  
M1.7 10:01   13765 GOES16  
C3.9 11:21   13781 GOES16  
C4.9 11:33   13777 GOES16 simultaneous flare in AR 13774
C4.1 12:17   13780 GOES16  
C4.4 12:23   13774 GOES16  
C3.7 13:06   13780 GOES16  
X1.7 13:39   13765 GOES16 CME, moderate type II radio sweep, small proton event
X1.1/2B 15:27 S08E55 13780 GOES16 moderate type II radio sweep
C6.0 16:19   13780 GOES16  
C6.0 16:50   13780 GOES16  
C5.6 16:57   13774 GOES16  
M1.0 18:02   13765 GOES16  
M1.2/1F 18:37   13780 GOES16  
C9.7 18:45   S9977 GOES16  
C3.7 19:24   13777 GOES16  
C3.6 19:48   13781 GOES16  
C3.5 20:29   13775 GOES18 simultaneous flare behind the southwest limb
C3.4 20:50   S9977 GOES18  
C3.9 23:05   13774 GOES18  
C4.6 23:24   13781 GOES18  

Coronal mass ejections (CMEs)

August 3-5: 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 2 N23W55 0130 HSX CSO location: N22W53
13772 2024.07.29
2024.07.30
17 27 17 S25W20 0330 EKI EKO beta-gamma

area: 0500

location: S24W21

S9969 2024.07.29       N08W47            
13775 2024.07.30
2024.07.31
15 24 9 N18W07 0130 DAO DSO beta-gamma

location: N18W05

13774 2024.07.30 28 84 37 S07E03 0400 EKC EHC beta-gamma

area: 0750

S9977 2024.07.30   7 4 N05W62 0030   CRO  
13776 2024.07.31
2024.08.01
  2   N09W21 0003   AXX

location: N09W19

13778 2024.07.31
2024.08.02
      S18W89            
13777 2024.08.01
2024.08.02
10 30 18 S09E21 0130 DAO EAO location: S08E18

area: 0270

S9983 2024.08.01       S19W41            
S9984 2024.08.02   14 8 S14E05 0070   DRO see AR 13779 which was relocated to this spot group on 2024.08.05
S9985 2024.08.02       N22E05            
S9986 2024.08.03       S28E29          
S9987 2024.08.03       N04W24            
13780 2024.08.03
2024.08.04
33 62 42 S13E58 0930 FKC FKC beta-gamma-delta

location: S09E60

area: 1600

13779 2024.08.03
2024.08.04
3     S15E10 0060 DAO       SWPC has changed the location of the spot group to that of AR S9984
S9992 2024.08.03       N18E46            
13781 2024.08.04
2024.08.05
2 5 2 N13E67 0160 DSO CAO location: N14E66

area: 0250

S9995 2024.08.05   1 1 N07E21 0010   HRX    
S9996 2024.08.05   1   N39E11 0002   AXX    
Total spot count: 109 261 140  
Sunspot number: 189 381 240  (total spot count + 10 * number of spotted regions)
Weighted SN: 164 320 199  (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): 208 210 192  

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  242.8 (1)   34.8 (2A) / 216.0 (2B) / 230.3 (2C) (151.3 projected, -0.1) (18.7)
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.