Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 10, 2024 at 07:25 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 (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 (July 1, 2024) Noon SDO sunspot count 1K image / 4K (*)
  Solar cycles 1-24 (July 1, 2020) POES auroral activity level [October 2009 - December 2012]
  Comparison of cycles 21-25 (July 1, 2024) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (July 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 July 9. 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 178.2 - increasing 13.3 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 163.25. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 163.32 on January 7, 2024). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 5.6). Three hour interval K indices: 22122112 (planetary), ******** (Boulder), 33123333 (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: 319) and in 14 active regions using 1K resolution (SN: 230) SDO/HMI images.

Region 13736 [S20W14] was mostly quiet and stable.
Region 13738 [S09E14] developed further and has two small magnetic delta configurations, one in the intermediate spot section, one in the leading spot section. A major flare is possible.
Region 13739 [N03W59] was quiet and stable.
Region 13740 [S18W44] was quiet and stable.
Region 13741 [N08E36] was mostly quiet and stable.
New region 13742 [S24E69] began to rotate into view on July 7 and was numbered by SPWC 2 days later. An M class flare is possible.
New region 13743 [S08E65] rotated into view on June 8 and received its NOAA number the following day.
New region 13744 [N16E79] rotated into view and may be capable of M class flaring.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9875 [S15W00] was quiet and stable.
S9877 [S24W18] was quiet and stable.
S9881 [S18E70] was quiet and stable.
New region S9884 [N17E21] emerged with tiny spots.
New region S9885 [S04E26] was observed with tiny spots in an old plage area.
New region S9886 [S22E26] was observed with a tiny spot in an old plage area.
New region S9887 [S23W56] emerged with a tiny spot.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.5 02:50   13736 GOES16  
C2.5 03:19   13742 GOES16  
C2.9 03:41   13738 GOES16  
C2.8 05:34   13736 GOES16 CME?
C5.6 05:58   13738 GOES16  
C5.1 07:25   13738 GOES16  
C6.7 08:22   13738 GOES16  
C2.2 09:46   13738 GOES16  
C2.3 10:42   13741 GOES16  
C2.5 12:16   13742 GOES16  
C3.2 12:52   13738 GOES16  
C2.7 14:38   13738 GOES16  
C2.9 15:09   13738 GOES16  
C2.4 17:07   13734 GOES16  
C2.3 18:22   13738 GOES16  
C2.4 19:43   13743 GOES16  
C5.0 22:06   13744 GOES16 SWPC incorrectly attributed this to smaller, simultaneous flare in AR 13738

Coronal mass ejections (CMEs)

July 7-9: No obviously Earth directed CMEs 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 poorly defined negative polarity southern hemisphere coronal hole (CH1230) was in an Earth facing position on July 6-7. A well defined positive polarity northern hemisphere coronal hole (CH1231) will rotate across the central meridian on July 9-11.

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 to fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet to unsettled on July 10-11 due to potential effects associated with CH1230. Quiet to active conditions are likely on July 12-13 due to effects from CH1231.

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
13734 2024.06.28
2024.06.29
      N08W73         location: N08W68
13735 2024.06.29
2024.06.29
      N17W59            
13736 2024.07.02
2024.07.03
3 11 5 S19W14 0040 HSX CSO location: S20W14

area: 0130

S9859 2024.07.03       S27W11            
13739 2024.07.04
2024.07.06
1 8 3 N04W56 0010 AXX DRO location: N03W59
13738 2024.07.04
2024.07.05
50 84 52 S08E14 0320 EKI FKC beta-gamma-delta

area: 1140

location: S09E14

13740 2024.07.04
2024.07.06
2 10 7 S18W47 0010 BXO BXI

location: S18W44

area: 0020

S9868 2024.07.05       N32W54            
S9869 2024.07.05       N27W40            
S9870 2024.07.06       S20W26          
S9872 2024.07.06       S07W02            
13741 2024.07.07
2024.07.07
1 6 1 N09E33 0010 AXX CRO area: 0020

location: S08E36

13742 2024.07.07
2024.07.09
2 6 3 S24E56 0060 CSO FHO area: 0320

location: S24E69

SWPC position is way off

S9875 2024.07.07   6 2 S15W00 0013   BXO  
S9876 2024.07.07       N21W32            
S9877 2024.07.07   9 3 S24W18 0025   BXO  
13743 2024.07.08
2024.07.09
3 11 6 S09E62 0030 CAO DAO area: 0140

location: S08E65

S9880 2024.07.08       N09W13          
S9881 2024.07.08   5 3 S18E70 0050   DRO  
S9882 2024.07.08       S11W14          
13744 2024.07.09
2024.07.09
1 2 1 N16E76 0090 HSX HKX   was AR S9883

area: 0290

location: N16E79

S9884 2024.07.09   7 2 N17E21 0010   AXX    
S9885 2024.07.09   2 1 S04E26 0004   AXX    
S9886 2024.07.09   1 1 S22E26 0004   AXX    
S9887 2024.07.09   1   S23W56 0001   AXX    
Total spot count: 63 169 90  
Sunspot number: 143 319 230  (total spot count + 10 * number of spotted regions)
Weighted SN: 93 218 139  (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): 157 175 184  

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
2022.10 133.5 132.7 95.5 98.9 (+2.4) 11.16
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 (128.9 projected, -0.5) 5.46
2024.02 172.5 168.3 123.0 (129.4 projected, +0.5) 5.31
2024.03 154.4 152.9 103.7 (130.3 projected, +0.9) 11.03
2024.04 161.3 162.6 136.5 (131.0 projected, +0.7) 9.69
2024.05 187.7
(cycle peak)
191.9 171.7 (SC25 peak) (133.2 projected, +2.2) 23.56
(SC25 peak)
2024.06 184.3 190.2 164.2 (134.9 projected, +1.7) 10.24
2024.07 169.4 (1)   41.1 (2A) / 141.6 (2B) / 158.6 (2C) (134.7 projected, -0.2) (5.9)
2024.08       (134.1 projected, -0.6)  
2024.09       (134.4 projected, +0.1)  
2024.10       (134.3 projected, -0.1)  
2024.11       (132.3 projected, -2.0)  
2024.12       (128.0 projected, -4.3)  
2025.01       (124.0 projected, -4.0)  

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 July 5, 2024

Sunspot counts in June 2024 were almost at the level of May 2024 and the second highest month during solar cycle 25. Looking at the projected activity for the remainder of this year, solar max now looks likely to occur between May and October 2024. A big decrease in sunspot formation in July 2024 and over the next months could change the projected maximum to earlier in 2024 or even to December 2023.

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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.