Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 14, 2024 at 05:10 UT. Active region table to be updated.

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 very quiet levels on July 13. 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 238.7 - increasing 71.4 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 163.47. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 163.47 on January 13, 2024). The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.4). Three hour interval K indices: 11101111 (planetary), ******** (Boulder), 20102113 (Andenes).

The background x-ray flux is at the class C4 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 17 active regions using 2K resolution (SN: 487) and in 14 active regions using 1K resolution (SN: 294) SDO/HMI images.

AR 13736 [S19W68] decayed slowly and quietly.
AR 13738 [S09W42] saw a strong increase in flare activity during the day and early on July 14. The largest flare was an X1.2 event at 02:34 UT on July 14 and it had its origin in the southernmost large penumbra. The spot group has several magnetic delta configurations and could produce further major flares.
AR 13741 [N10W17] was quiet and stable.
AR 13742 [S24E18] produced a few M flares and displayed no significant changes.
AR 13743 [S08E09] developed slowly and could produce an M class flare.
AR 13744 [N16E26] developed slowly and was mostly quiet.
AR 13745 [S18E17] developed slowly and was mostly quiet. A merge between this and AR 13742 is being considered due to no obvious separation between the spot groups.
AR 13748 [N15E42] decayed slowly and quietly.
New AR 13749 [S32E68] rotated into view on July 12 and was numbered by SWPC the next day.
New AR 13750 [S20E67] rotated into view on July 12 and received its NOAA number the following day.
New AR 13751 [S08E79] rotated into view and appears to have M class flare potential.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9884 [N18W32] was quiet and stable
S9888 [N11E07] was merged with AR S9892 and was quiet and stable.
S9895 [S08E18] was quiet and stable to the east of AR 13743.
New region S9900 [N22E80] rotated into view with a small spot.
New region S9901 [N35E27] was observed with tiny spots in an old plage area.
New region S9902 [N25E01] was observed with tiny spots in an old plage area.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.2 00:25   13738 GOES16  
C3.1 01:31   13738 GOES16  
C2.8 02:39   13738 GOES16  
M1.4 03:17   13738 GOES16  
C7.0 03:47   13738 GOES16  
C8.1 04:15   13751 GOES16  
C8.3 04:20   13751 GOES16 incorrectly attributed to AR 13738 by SWPC
simultaneous flare in AR 13749
C8.0 04:35   13751 GOES16 incorrectly attributed to AR 13738 by SWPC
C9.5 05:10   13738 GOES16  
C6.1 05:39   13751 GOES16  
C4.1 06:17   13751 GOES16  
C3.4 07:04   13751 GOES16 simultaneous flare in AR 13743
C2.9 07:38   13738 GOES16  
C2.7 08:13   13738 GOES16  
C2.8 09:42   13738 GOES16  
C2.7 10:29   13743 GOES16  
C3.5 12:07   13751 GOES16 incorrectly attributed to AR 13738 by SWPC
C4.6 12:19   13743 GOES16 incorrectly attributed to much smaller flare in AR 13738 by SWPC
M5.3/1N 12:42 S08W42 13738 GOES16 weak type II radio sweep
M1.0 13:24   13742 GOES16  
C5.2 14:14   13751 GOES16 incorrectly attributed to AR 13738 by SWPC
C5.4 14:19   13738 GOES16  
C5.4 14:27   13738 GOES16  
C5.8 14:40   13738 GOES16  
C5.7 14:50   13738 GOES16  
C6.2 14:56   13738 GOES16  
M1.8 15:29   13742 GOES16  
M1.9 15:44   13738 GOES16  
C8.2 16:48   13751 GOES16 simultaneous flare in AR S9900
C6.0 17:14   13738 GOES16  
C3.9 18:34   13738 GOES16  
C5.6 18:50   13738 GOES16  
M1.0 19:30   13738 GOES16  
C7.6 20:02   13751 GOES16 simultaneous flare in AR 13738
C6.7 20:52   S9900 GOES16  
C6.0 21:11   13738 GOES16  
C4.9 22:11   13751 GOES16  
M5.0 23:01   13738 GOES16  

Coronal mass ejections (CMEs)

July 11-13: 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 well defined positive polarity northern hemisphere coronal hole (CH1231) rotated 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 fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet to unsettled on July 14-16.

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
13736 2024.07.02
2024.07.03
1 3 2 S21W54 0020 HAX HRX location: S20W54
S9859 2024.07.03       S27W50            
13738 2024.07.04
2024.07.05
50 101 60 S09W26 1100 FKI FKC beta-gamma-delta

location: S09W28

13740 2024.07.04
2024.07.06
      S18W89        

location: S17W83

S9872 2024.07.06       S07W41            
13741 2024.07.07
2024.07.07
  6   N09W09 0008   BXO location: N08W09
13742 2024.07.07
2024.07.09
4 31 16 S23E16 0010 BXO FSO area: 0250

location: S25E32

SWPC split off the trailing spot section into AR 13747 on 2024.07.11
There's unfortunately no obvious reason for this split

The original interpretation will not be changed as of now

S9875 2024.07.07       S13W40          
S9877 2024.07.07       S24W57            
13743 2024.07.08
2024.07.09
12 58 29 S09E24 0200 DSI DAI beta-gamma

area: 0300

location: S09E26

S9880 2024.07.08       N09W52            
13745 2024.07.08
2024.07.10
2 12 7 S17E31 0020 BXO DRO area: 0030
S9882 2024.07.08       S11W53            
13744 2024.07.09
2024.07.09
7 27 11 N16E43 0180 DSO DSI

beta-gamma

area: 0220

location: N15E40

S9884 2024.07.09   4 2 N18W19 0007   AXX  
S9885 2024.07.09   7   S07W11 0010   BXO  
S9886 2024.07.09   2   S24W15 0004   AXX  
S9888 2024.07.10   19 7 N13E17 0040   BXO  
13746 2024.07.10
2024.07.11
      N23W37        

location: N21W36

S9890 2024.07.10       S46W20            
13748 2024.07.10
2024.07.12
4 16 5 N15E57 0030 BXO DRO  
S9892 2024.07.10   12   N07E24 0015   BXO  
S9893 2024.07.10       N40E06            
13747 2024.07.11 2     S25E32 0180 HSX       AR 13747 is the trailing spot section of AR 13742
S9895 2024.07.12   7 4 S11E36 0020   DRO    
S9896 2024.07.12   1 1 N18W46 0003   AXX    
S9897 2024.07.12   5 4 S20E80 0080   DRI    
S9898 2024.07.12   3 2 S32E81 0070   DAO    
Total spot count: 82 314 150  
Sunspot number: 162 484 280  (total spot count + 10 * number of spotted regions)
Weighted SN: 112 359 195  (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): 178 266 224  

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
2024.07 179.4 (1)   57.2 (2A) / 147.8 (2B) / 167.3 (2C) (134.7 projected, -0.2) (5.7)
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.