Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 15, 2024 at 03:25 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 (August 11, 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 active levels on August 14. 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 248.2 - increasing 24.4 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 169.16. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 169.16 on February 14, 2024). The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.5). Three hour interval K indices: 43211113 (planetary), 44223513 (Boulder), 55112223 (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: 312) and in 11 active regions using 1K resolution (SN: 196) SDO/HMI images.

AR 13780 [S09W62] decayed significantly losing spots, area and complexity. Although only a few flares were observed during the day, there is still a chance of a major flare.
AR 13781 [N15W54] decayed slowly and quietly.
AR 13782 [N04W28] decayed slowly and quietly.
AR 13783 [N12W66] decayed slowly and quietly.
AR 13784 [N15W04] has a strong magnetic delta configuration in the main penumbra and a smaller delta in a trailing penumbra. X flares are possible.
AR 13785 [S11E08] decayed slowly and quietly.
AR 13786 [S22W41] was mostly quiet and stable.
AR 13788 [S07E20] decayed slowly and was mostly quiet.
New region 13789 [N28E27] was first observed with spots on August 10, then became spotless. New spots emerged on August 13 and SWPC numbered the region the next day as it began to decay.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S10011 [S06W13] was quiet and stable.
S10016 [S09W23] decayed slowly and quietly.
New region S10019 [S18E73] rotated into view with tiny spots.

Old AR 13765 could be the source of 2 M flares from behind the southeast limb. Further major flares are possible.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C4.9 01:45   13784 GOES16  
C4.8 02:05   13784 GOES16  
C4.7 02:20   13784 GOES16  
C6.2 02:50   13784 GOES16 simultaneous flare in AR 13777
C9.2 03:16 N13E07 13784 GOES16  
C6.6 03:25   13784 GOES16 simultaneous flare in AR 13777
M4.4 04:02   13777 GOES16 LDE, simultaneous flare in AR 13784
M1.8 04:41   13784 GOES16  
C9.3 05:27   13784 GOES16  
X1.1/2B 06:40   13784 GOES16 LDE, halo CME, moderate type II and weak type IV radio sweep
C7.8 08:15   13784 GOES16  
C8.9 08:25   13784 GOES16  
C5.7 10:00   13784 GOES16  
C6.4 10:42   13784 GOES16  
C6.7 11:03 behind southeast limb (S11E90)   GOES16  
C6.2 11:44   13784 GOES16  
M1.0 13:23 behind southeast limb (S11E90)   GOES16 SWPC incorrectly attributes this to simultaneous smaller flare in AR 13784
C7.9 15:42   13784 GOES16  
M5.3 15:49 behind southeast limb (S11E90)   GOES16 SWPC incorrectly attributes this to AR 13784
C9.5 17:22   13784 GOES16  
C7.6 17:40   13784 GOES16  
C8.6 18:06 behind southeast limb (S11E90)   GOES16  
C7.2 18:18   13780 GOES16  
C6.8 19:47   13784 GOES16  
C4.9 21:08   13784 GOES16  
C5.7 21:39   13780 GOES16  

Coronal mass ejections (CMEs)

August 12-13: No obviously Earth directed CMEs were observed.
August 14: A slow moving full halo CME was observed after the X1 flare in AR 13784. The CME could reach Earth on August 17.

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 recurrent negative polarity northern hemisphere coronal hole (CH1235) will be rotating across the central meridian on August 13-15, however, it is likely too far to the north to cause any signifcant disturbance. A positive polarity northern hemisphere coronal hole (CH1236) could rotate into an Earth facing position on August 19.

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 to unsettled levels on August 15-16. The August 14 CME could cause unsettled to major storm levels on August 17-18.

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
13777 2024.08.01
2024.08.02
1     S09W99 0250 DKC     rotated out of view earlky in the day
13780 2024.08.03
2024.08.04
26 33 18 S08W63 0930 FKC FKC beta-gamma-delta

area: 0850

location: S09W62

13781 2024.08.04
2024.08.05
1 3 1 N15W56 0090 HSX CSO

area: 0150

location: N15W54

13782 2024.08.06
2024.08.07
4 16 5 N03W27 0030 CAO CAO location: N04W28
13783 2024.08.07
2024.08.08
1 2 1 N12W67 0010 AXX HRX location: N12W66
13784 2024.08.07
2024.08.09
30 42 25 N14W05 0700 DKC EKC beta-gamma-delta

area: 1160

13786 2024.08.07
2024.08.11
9 36 14 S22W41 0080 CAO DSI  
S10006 2024.08.08       S09W08            
13785 2024.08.09
2024.08.11
12 33 9 S11E07 0020 BXI CRI

location: S11E08

13787 2024.08.09
2024.08.11
      N17W43         location: N18W42
S10011 2024.08.10   3 1 S06W13 0010   BXO  
13788 2024.08.10
2024.08.11
7 11 8 S08E21 0130 DSO DAO location: S07E20

area: 0170

13789 2024.08.10
2024.08.14
3 4 3 N25E26 0010 BXO BXO  
S10014 2024.08.11       S27W29            
S10015 2024.08.11       N18W21            
S10016 2024.08.12   2   S09W23 0002   AXX  
S10018 2024.08.12       S20E03            
S10019 2024.08.14   2 1 S18E73 0005   AXX    
Total spot count: 94 192 86  
Sunspot number: 194 312 196  (total spot count + 10 * number of spotted regions)
Weighted SN: 144 238 132  (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): 213 172 157  

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 (137.4 projected, +6.3) 5.31
2024.03 154.4 152.9 103.7 (144.1 projected, +6.7) 11.03
2024.04 161.3 162.6 136.5 (148.2 projected, +4.1) 9.69
2024.05 187.7 191.9 171.7 (152.9 projected, +4.7) 23.56
(SC25 peak)
2024.06 184.3 190.2 164.2 (156.9 projected, +4.0) 10.24
2024.07 196.6
(cycle peak)
203.0 196.5  (SC25 peak) (158.7 projected, +1.8) 7.13
2024.08  267.6 (1)   107.0 (2A) / 237.0 (2B) / 238.0 (2C) (159.1 projected, +0.4) (21.4)
2024.09       (161.0 projected, +1.9)  
2024.10       (162.8 projected, +1.8)  
2024.11       (160.8 projected, -2.0)  
2024.12       (156.4 projected, -4.4)  
2025.01       (150.3 projected, -6.1)  
2025.02       (143.0 projected, -7.3)  

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 12, 2024

Sunspot counts in July 2024 were the highest we've seen for a single month during solar cycle 25. The first part of August has seen very high sunspot counts, and there more than a remote possibility that we'll see activity in August approaching the most active months of solar cycle 23. With at least 4 consecutive months of high sunspot counts the projected peak for the smoothed ISN (365 days smoothing) has increased significantly to above 160. The month of the peak is currently likely to occur sometime between July and November 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.