Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 16, 2024 at 06:35 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 oothing 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 unsettled levels on July 15. The high latitude magnetometer at Andenes recorded quiet to major storm levels. The above 10 MeV proton flux was at background levels at the end of the day. A transient (CME) was observed reaching ACE+DSCOVR near 21:35 UT and caused a disturbance late in the day and early on July 16.

Solar flux density measured at 20h UT on 2.8 GHz was 233.2 - increasing 40.5 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 163.76. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 163.76 on January 15, 2024). The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 5.3). Three hour interval K indices: 11111113 (planetary), ******** (Boulder), 11112126 (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 23 active regions using 2K resolution (SN: 576) and in 20 active regions using 1K resolution (SN: 370) SDO/HMI images.

AR 13738 [S08W70] lost spots and continued to produce C and M flares.
AR 13742 [S25W06] decayed slowly and quietly.
AR 13743 [S09W15] developed further and has minor polarity intermixing.
AR 13744 [N16W02] decayed slightly and could still produce a minor M class flare.
AR 13745 [S19W09] developed slowly and was mostly quiet.
AR 13748 [N15E15] was quiet and stable.
AR 13749 [S33E42] was quiet and stable.
AR 13750 [S20E41] developed slowly and quietly.
AR 13751 [S08E51] developed further becoming a compact region with a weak magnetic delta configuration. M flares are possible.
AR 13752 [N23E57] developed slowly and quietly.
New AR 13753 [N11W22] developed further and was quiet.
New AR 13754 [N25E70] rotated into view on July 14 and was numbered the next day by SWPC.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9884 [N15W49] reemerged with tiny spots.
S9885 [S07W50] reemerged with a tiny spot.
S9895 [S08W09] developed slowly and quietly.
New region S9907 [N22E68] was split off from AR 13754.
New region S9908 [N02E75] rotated into view.
New region S9909 [S17E80] rotated into view with a mature spot.
New region S9910 [S29E02] emerged with a tiny spot.
New region S9911 [N18E87] began to rotate into view late in the day.
New region S9912 [N29W33] was observed with tiny spots in an old plage area.
New region S9913 [S21E16]  was observed with tiny spots in an old plage area.
New region S9914 [S06E29] emerged with a tiny spot.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.8 00:25   13738 GOES16  
C3.1 01:23   13751 GOES16  
C3.1 01:29   13738 GOES16  
C3.3 02:06   13738 GOES16  
C3.8 02:21   13738 GOES16  
C3.2 02:34   13738 GOES16  
C3.3 03:08   13738 GOES16  
C3.8 03:12   13751 GOES16  
M1.2 03:45 S11W57 13738 GOES16  
C4.2 04:20   13738 GOES16  
C3.6 04:48   13744 GOES16  
C7.1 05:12   13744 GOES16  
C3.2 07:40   13744 GOES16  
C2.9 08:09   13744 GOES16  
C4.3 08:29   13738 GOES16  
C3.8 08:41   13738 GOES16  
C3.7 09:19   13738 GOES16  
M2.7 09:37   13738 GOES16  
M1.9 10:13   13738 GOES16 simultaneous flare in AR 13754
M1.1 10:39   13754 GOES16 simultaneous flare in AR 13738
C4.8 12:54   13751 GOES16 simultaneous flare in AR 13738
C4.6 13:22   13744 GOES16  
C4.9 13:42   13738 GOES16  
C5.1 15:21   13743 GOES16  
C4.5 16:17   13738 GOES16  
C3.2 17:24   13751 GOES16  
C3.7 18:11   13742 GOES16  
C4.2 18:32   13750 GOES16  
C5.0 18:56   13751 GOES16 simultaneous flare in AR 13738
C7.9 20:08   13751 GOES16  
C8.2 21:25   13742/13745 GOES16  
C9.8 21:37   13750 GOES16  
C7.5 22:15   13738 GOES16  
C9.4 22:33   13751 GOES16 simultaneous flare in AR 13738
C7.3 22:48   13750 GOES16  
C6.4 23:21   13751 GOES16  

Coronal mass ejections (CMEs)

July 13-15: 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 large recurrent negative polarity coronal hole (CH1232) in the northern hemisphere will be rotating across the central meridian on July 14-16.

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 on July 15-17.

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
13738 2024.07.04
2024.07.05
19 33 16 S09W68 1010 FKC FKC beta-gamma-delta

location: S08W70

13741 2024.07.07
2024.07.07
      N09W51           location: N10W43
13742 2024.07.07
2024.07.09
  14 8 S21W25 0190   HSX

location: S25W06

SWPC split off the trailing spot section into AR 13747 on 2024.07.11

13743 2024.07.08
2024.07.09
15 58 35 S08W17 0140 DAI EAI

beta-gamma

area: 0210

location: S09W15

13745 2024.07.08
2024.07.10
3 26 10 S18W11 0020 CSO DRO area: 0060

location: S19W09

13744 2024.07.09
2024.07.09
7 33 12 N16W01 0120 CSO DAI

beta-gamma

area: 0160

location: N16W02

S9884 2024.07.09   3 3 N15W49 0012   HRX    
S9885 2024.07.09   1 1 S08W50 0003   AXX    
S9886 2024.07.09       S24W54            
13753 2024.07.10
2024.07.15
7 35 16 N12W22 0050 DAO DAI location: N11W22

area: 0240

13746 2024.07.10
2024.07.11
      N23W78          

location: N21W75

13748 2024.07.10
2024.07.12
4 19 10 N14E14 0010 BXO DRI area: 0050

location: N15E15

S9893 2024.07.10       N40W33            
13747 2024.07.11 2     S25W07 0130 HSX       AR 13747 is the trailing polarity section of AR 13742
S9895 2024.07.12   22 12 S08W09 0070   DRI  
13750 2024.07.12
2024.07.13
9 31 13 S20E38 0090 CAO DAI beta-gamma

location: S20E41

area: 0200

13749 2024.07.12
2024.07.13
4 8 3 S32E36 0040 CAO EAO area: 0070

location: S33E42

13751 2024.07.13
2024.07.13
10 33 15 S08E54 0220 DSI EAC

beta-gamma-delta

location: S08E52

area: 0550

13752 2024.07.13
2024.07.14
1 5 4 N22E53 0030 HSX DSO area: 0070

location: N23E57

S9901 2024.07.13       N35W04          
S9902 2024.07.13       N25W25            
13754 2024.07.14 4 5 4 N23E69 0030 DRO DAO southernmost spots split off into AR S9907

location: N25E70

area: 0100

S9904 2024.07.14       N16E37          
S9905 2024.07.14       S35E24          
S9906 2024.07.14       S24W35          
S9907 2024.07.15   3 1 N22E68 0010   CRO    
S9908 2024.07.15   7 3 N02E75 0060   DAO    
S9909 2024.07.15   1 1 S17E80 0150   HSX    
S9910 2024.07.15   1 1 S29E02 0003   AXX    
S9911 2024.07.15   1   N18E87 0050   HSX    
S9912 2024.07.15   2   N29W33 0003   AXX    
S9913 2024.07.15   4 2 S21E16 0008   AXX    
S9914 2024.07.15   1   S06E29 0001   AXX    
Total spot count: 85 346 170  
Sunspot number: 205 576 370  (total spot count + 10 * number of spotted regions)
Weighted SN: 143 427 246  (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): 226 317 296  

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
2024.07 190.5 (1)   77.7 (2A) / 160.7 (2B) / 180.2 (2C) (134.7 projected, -0.2) (5.4)
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.