Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 16, 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 (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 levels on August 15. The high latitude magnetometer at Andenes recorded quiet to unsettled 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 227.4 - increasing 18.7 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 169.35. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 169.35 on February 14, 2024). The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.9). Three hour interval K indices: 10102112 (planetary), 21112423 (Boulder), 21003223 (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 15 active regions using 2K resolution (SN: 372) and in 14 active regions using 1K resolution (SN: 236) SDO/HMI images.

AR 13780 [S08W75] decayed further and produced only a few flares as the spot group began to transit the west limb.
AR 13781 [N15W68] was quiet and stable.
AR 13782 [N04W42] decayed slowly and quietly.
AR 13784 [N15W18] still has a strong magnetic delta configuration in the main penumbra. Some loss of area was observed and the spot group appears to be slowly decaying. X flares are possible.
AR 13785 [S11W05] developed slowly and was mostly quiet.
AR 13786 [S22W53] developed slowly as new flux emerged in the trailing spot section. Many C flares were recorded during the day.
AR 13787 [N19W52] reemerged with tiny spots.
AR 13788 [S07E07] was quiet and stable.
AR 13789 [N27E12] developed and gained many tiny spots. C flares are possible.
New AR 13790 [S12E74] rotated into view with mostly small spots. The region produced several flares while behind the southeast limb and was mostly quiet during its first day on the visible disk.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S10015 [N21W36] reemerged with tiny spots.
S10016 [S10W38] was quiet and stable.
S10019 [S18E60] gained a few spots and was quiet.
New region S10021 [N06E03] emerged with tiny spots.
New region S10022 [S07E35] was observed with tiny spots in an old plage area.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C4.0 00:29   13784 GOES16  
C4.2 01:16   13790 GOES16  
C7.0 01:24 N14W08 13784 GOES16 simultaneous flare in AR 13780
C5.6 01:36   13790 GOES16  
C6.8 02:09 N11W07 13784 GOES16  
M1.1 03:48 S10W62 13780 GOES16  
C4.3 04:12   13780 GOES16  
C4.7 04:19   13780 GOES16  
C4.6 04:54   13786 GOES16 simultaneous flare in AR 13780
C4.2 05:05   13780 GOES16  
C5.6 05:24 N13W08 13784 GOES16  
C5.8 05:54 N15W10 13784 GOES16  
C4.9 06:14   13784 GOES16 simultaneous flare behind the northeast limb
C5.0 06:22   13786 GOES16  
C4.7 06:28   13786 GOES16  
C3.8 08:07   13786 GOES16  
C4.0 08:57   13784 GOES16  
C5.7 09:11 S22W43 13786 GOES16  
C4.6 10:57   13784 GOES16  
C4.2 11:40   13786 GOES16  
C7.7 11:50 S24W44 13786 GOES16  
C5.1 12:08   13784 GOES16  
C4.0 13:09   13784 GOES16  
C3.7 13:19   13784 GOES16  
C4.2 13:54   13786 GOES16  
C5.6 14:07   13780 GOES16 SWPC attributes this to smaller, simultaneous flare in AR 13786
C5.4 14:11   13784 GOES16  
C3.6 15:04   13784 GOES16  
C7.8 17:35   13786 GOES16  
C4.1 19:05   13784 GOES16 simultaneous flare in AR 13790
C4.0 19:15   13780 GOES16  
C4.0 20:48   13790 GOES16 simultaneous flare in AR 13784
C3.1 21:54   13784 GOES16  
C3.4 22:27   13780 GOES16  

Coronal mass ejections (CMEs)

August 13, 15: 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
13780 2024.08.03
2024.08.04
15 19 8 S09W74 0410 FKI DKC beta-gamma-delta

area: 0550

location: S08W75

13781 2024.08.04
2024.08.05
1 1 1 N15W69 0070 HSX HSX

area: 0130

location: N15W68

13782 2024.08.06
2024.08.07
2 8 2 N03W44 0020 HAX CRO location: N04W42
13783 2024.08.07
2024.08.08
1     N11W82 0010 AXX     location: N12W79

spotless

13784 2024.08.07
2024.08.09
23 58 26 N15W19 0680 EKC DKC beta-gamma-delta

area: 0900

location: N15W18

13786 2024.08.07
2024.08.11
13 27 13 S22W54 0080 CAO DSI beta-gamma

location: S22W53

S10006 2024.08.08       S09W21            
13785 2024.08.09
2024.08.11
10 38 14 S12W06 0010 BXO DRI

location: S11W05

area: 0050

13787 2024.08.09
2024.08.11
  3 1 N17W56 0010   BXO   location: N19W52
S10011 2024.08.10       S06W26          
13788 2024.08.10
2024.08.11
4 18 6 S07E09 0100 CSO DAO location: S07E07

area: 0150

13789 2024.08.10
2024.08.14
  23 10 N26E12 0060   DRI beta-gamma

location: N27E12

S10014 2024.08.11       S27W42            
S10015 2024.08.11   1 1 N21W36 0003   AXX    
S10016 2024.08.12   1   S10W38 0001   AXX  
S10018 2024.08.12       S20W10            
S10019 2024.08.14   6 4 S18E60 0020   CRO  
13790 2024.08.15
2024.08.15
5 11 7 S14E72 0040 CSO DSI   beta-gamma

was AR S10022

location: S12E74

area: 0120

S10021 2024.08.15   3 1 N06E03 0008   BXO    
S10022 2024.08.15   5 2 S07E35 0010   BXO    
Total spot count: 74 222 96  
Sunspot number: 164 372 236  (total spot count + 10 * number of spotted regions)
Weighted SN: 119 274 148  (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): 180 205 189  

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  264.9 (1)   112.3 (2A) / 232.1 (2B) / 233.7 (2C) (159.1 projected, +0.4) (20.3)
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.