Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 2, 2024 at 07:10 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 (July 3, 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 minor storm levels on August 1 due to CME effects. 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 234.4 - increasing 68.8 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 165.14. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 165.14 on February 1, 2024). The Potsdam WDC planetary A index was 18 (STAR Ap - based on the mean of three hour interval ap indices: 18.3). Three hour interval K indices: 54423222 (planetary), ******** (Boulder), 54523222 (Andenes).

The background x-ray flux is at the class C5 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 17 active regions using 2K resolution (SN: 478) and in 16 active regions using 1K resolution (SN: 320) SDO/HMI images.

AR 13763 [N05W62] was quiet and stable.
AR 13764 [S02W56] was quiet and stable.
AR 13765 [S11W45] developed slightly and produced several flares.
AR 13766 [S07W55] decayed slowly and was mostly quiet.
AR 13767 [S08W39] decayed slowly and was mostly quiet.
AR 13768 [S15W80] rotated partly out of view and produced many C and M flares.
AR 13769 [N22W01] was quiet and stable.
AR 13770 [N08W42] decayed losing area and spots. There is one mangeti delta configuration left and still a chance of a minor M class flare.
AR 13772 [S23E33] developed further and could produce major flares.
AR 13773 [S07W71] decayed losing nearly all spots and area.
AR 13774 [S07E56] is a compact and complex spot group which could produce an X class event.
AR 13775 [N18E48] developed and gained a magnetic delta configuration. A minor M class event is possible.
New AR 13776 [N09E36] emerged on July 31 and was numbered by SWPC the next day.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9969 [N08W09] reemerged with tiny spots.
S9981 [S19W35] was quiet and stable.
New region S9982 [S09E77] rotated into view with tiny spots.
New region S9983 [S19E12] was observed with tiny spots in an old plage area.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C9.3 00:08   13770 GOES16 simultaneous flares in ARs 13768, 13772, S9982
C8.3 00:33   13774 GOES16 simultaneous flares in ARs 13768, S9925, 13772
C6.6 00:46   13768 GOES16  
M1.1 00:54   13768 GOES16  
M1.2 00:58   13770 GOES16  
C8.3 01:33   13774 GOES16 simultaneous flare in AR 13768
C8.4 01:42   S9925 GOES16 simultaneous flares in ARs 13772, 13765, 13774
M6.3 01:50   13773 GOES16  
C9.5 02:02   13768 GOES16  
M1.0 02:25   13768 GOES16  
C9.2 02:36   13765 GOES16  
M1.2 03:06   13774 GOES16 simultaneous flares in ARs 13765, 13768, S9925
C7.9 03:45   13772 GOES16  
M1.9 04:09   13772 GOES16  
M1.9 04:16   13774 GOES16  
M4.0 04:41   13765 GOES16  
M1.1 05:05   13768 GOES16 simultaneous flares in ARs 13772, 13765
M1.2 05:36   13765 GOES16  
M1.2 05:39   13772 GOES16  
M1.1 05:48   13775 GOES16  
M1.5 05:55   13765 GOES16 attributed to simultaneous flare in AR 13768 by SWPC
M1.3 06:06   13775 GOES16 simultaneous flares at the northwest limb and in AR 13767
M1.6 06:40     GOES16  
M8.2/1N 07:09 S16W74 13768 GOES16 LDE, CME, moderate type II and IV radio sweeps
M2.3 08:08   13765 GOES16  
M1.7 08:30   13772 GOES16  
M1.1 09:09   13772 GOES16  
M1.0 09:33   13766 GOES16  
C8.5 09:55   13774 GOES16  
C8.4 10:33   13774 GOES16  
C9.5 11:06   13772 GOES16  
M3.3 11:28   13772 GOES16  
M4.1 11:37   13772 GOES16 attributed to simultaneous flare in AR 13768 by SWPC
M3.3 12:16   13768 GOES16  
M2.1 12:37   13773 GOES16  
C9.0 13:35   13772 GOES16 simultaneous flare in AR 13766
C6.6 14:18   13768 GOES16  
C7.5 14:32   13774 GOES16  
C7.3 14:41   13768 GOES16  
C5.5 15:05   13768 GOES16  
C8.8 15:15 S15W79 13768 GOES16  
C7.2 15:58   13774 GOES16  
C7.5 16:05   13768 GOES16  
M1.0 16:15   13764 GOES16  
C9.1 16:28   13768 GOES16  
M1.3 16:37   13768 GOES16 incorrectly attributed to AR 13765 by SWPC
M1.6 16:47   13774 GOES16  
M1.0 17:04   13774 GOES16  
M1.3 17:29 S03E63 13774 GOES16  
C8.4 17:49   13774 GOES16  
C8.5 18:10   13768 GOES16  
C8.5 18:55 S21E38 13772 GOES16 simultaneous flare in AR 13768
C6.4 19:26   13768 GOES16  
M1.2 20:22 S13E63 13774 GOES16  
C6.2 20:57   13774 GOES16  
C5.6 21:29   13768 GOES16  
C5.3 22:04   13768 GOES16  
M1.4 23:08   13774 GOES16 incorrectly attributed to AR 13772 by SWPC
C7.3 23:33   13772 GOES16  
C7.1 23:44   13774 GOES16  

Coronal mass ejections (CMEs)

August 1: An asymmetrical full halo CME was observed after an M8.2 flare in AR 13768 at 07:09 UT. Components of this CME could reach Earth on August 4.
July 30-31
: 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 trans equatorial coronal hole (CH1233) rotated across the central meridian on July 30-31, however, CH1233 was in decay most of July 30 and no significant disturbance is expected.

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 2-3 with a chance of active intervals should effects from CH1233 reach Earth. Quiet to minor storm levels are possible on August 4 due to effects from the August 1 CME.

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
13763 2024.07.21
2024.07.22
1 1 1 N05W64 0060 HSX HSX location: N05W62

area: 0190

13764 2024.07.22
2024.07.22
3 5 2 S03W62 0070 CSO CSO

area: 0140

location: S02W56

13765 2024.07.23
2024.07.23
28 42 23 S11W47 0450 EKC EKC

beta-gamma-delta

location: S11W45

13766 2024.07.24 21 35 21 S07W55 0180 EAI EHI

area: 0360

13767 2024.07.25 15 33 16 S09W38 0130 DAI DAI

area: 0250

location: S08W39

13768 2024.07.25
2024.07.26
24 9 7 S16W85 0500 FKC EKC beta-gamma-delta
13771 2024.07.25
2024.07.29
      N01W88           location: N00W82
13769 2024.07.25
2024.07.26
1 14 6 N22W04 0080 HSX CSO location: N22W01

area: 0210

13770 2024.07.27
2024.07.28
12 28 12 N07W45 0310 DHO DAC beta-delta

location: N08W42

area: 0330

S9966 2024.07.28       N30W19          
13772 2024.07.29
2024.07.30
12 50 26 S25E34 0240 EAC EKC beta-gamma-delta

area: 0700

location: S23E33

S9968 2024.07.29       N34W09            
S9969 2024.07.29   11 2 N08E05 0020   BXO    
S9970 2024.07.29       N11W28            
S9971 2024.07.29       N25W49            
S9972 2024.07.29       N24W23            
S9973 2024.07.29       S12W24            
13775 2024.07.30
2024.07.31
4 22 11 N17E46 0040 CSO DAC beta-delta

location: N18E48

area: 0140

13773 2024.07.30
2024.07.30
3 2 2 S06W73 0020 BXO HRX

area: 0010

location: S07W71

13774 2024.07.30 2 38 21 S06E55 0250 EKI EKC beta-gamma-delta

location: S07E56

area: 1030

SWPC forgot to update spot count and area from the previous day

S9977 2024.07.30       N05W07          
S9978 2024.07.30       N31W34            
13776 2024.07.31
2024.08.01
4 8 6 N10E34 0030 CRO DRO area: 0050

location: N09E36

S9981 2024.07.31   4 3 S19W35 0015   CRO  
S9982 2024.08.01   4 1 S09E77 0012   BXO    
S9983 2024.08.01   2   S19E12 0002   BXO    
Total spot count: 130 308 160  
Sunspot number: 260 478 320  (total spot count + 10 * number of spotted regions)
Weighted SN: 203 397 249  (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): 286 263 256  

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  234.4 (1)   8.4 (2A) / 260 (2B) / 221.7 (2C) (151.3 projected, -0.1) (18.3)
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.