Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 2, 2024 at 06:20 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 (June 9, 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 1. 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 170.6 - decreasing 21.7 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 163.22. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 163.22 on January 1, 2024). The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 4.9). Three hour interval K indices: 21212111 (planetary), 25322231 (Boulder), 23322323 (Andenes).

The background x-ray flux is at the class C1 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 19 active regions using 2K resolution (SN: 397) and in 18 active regions using 1K resolution (SN: 294) SDO/HMI images.

Region 13721 [N27W52] decayed slowly and quietly.
Region 13722 [S13W56] was quiet and stable.
Region 13723 [S20W29] was mostly quiet and stable
Region 13726 [S05W38] decayed slowly and quietly.
Region 13727 [S18W18] decayed slowly and quietly.
Region 13728 [S27W24] decayed slowly quietly.
Region 13729 [S04W01] gained spots and area. The region has polarity intermixing and could produce M flares. C1 flares: C1.6 @ 01:12 UT
Region 13730 [S18W45] gained spots and produced several flares including the largest flare of the day. C1 flares: C1.9 @ 00:28, C1.4 @ 08:00, C1.7 @ 08:28, C1.6 @ 13:43 UT
Region 13731 [S16E09] decayed slowly and quietly.
Region 13733 [N03W01] decayed slowly and quietly.
Region 13734 [N08E41] decayed in the trailing spot section while slow development was observed in the leading spot section.
Region 13735 [N17E48] was quiet and stable.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9830 [S07W19] decayed slowly and quietly.
S9838 [N23W22] decayed slowly and quietly.
S9843 [N09W01] was quiet and stable.
S9847 [S13E19] was quiet and stable.
New region S9854 [N23E19] emerged with tiny spots.
New region S9855 [S13W36] emerged with tiny spots.
New region S9856 [S28E08] was observed with tiny spots in an old plage area.

An active region behind the southeast limb was the source of a C1.8 flare at 20:16, a C1.9 flare at 21:38 and a C1.8 flare at 23:25 UT

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.1 03:16   13729 GOES16  
M2.1/1N 11:02   13730 GOES16  
C2.8 11:42   13729 GOES16  
C2.1 15:28   13729 GOES16  
C2.0 17:57 southwest limb 13720 GOES16  
C2.2 22:07 behind southeast limb   GOES16  
C3.6 22:33 behind southeast limb   GOES16  
C2.1 22:59 behind southeast limb   GOES16  

Coronal mass ejections (CMEs)

June 29: A faint full halo CME was observed after a large, multi stage filament eruption in the southern hemisphere. The eruption may have been triggered by a C2 flare in AR 13728 that occurred at 13:13 UT. The filament eruption spread westwards and covered a large area with the peak activity occurring between 15 and 16 UT. The associated CME was observed in LASCO C2 imagery from 16:12 UT.
June 30-July 1: 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 positive polarity northern hemisphere coronal hole (CH1229) could rotate into an Earth facing position on July 4-5.

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 quiet to minor storm on July 2-3 due to effects from the June 29 CME. Quiet conditions are likely on July 4.

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
13719 2024.06.19
2024.06.19
1     S17W94 0090 HAX     rotated out of view
13720 2024.06.19
2024.06.19
      S05W82          
13725 2024.06.20
2024.06.23
      N18W71           location: N22W68
13721 2024.06.21
2024.06.21
2 5 3 N26W55 0060 HAX CRO area: 0030

location: N27W52

13722 2024.06.21
2024.06.21
1 3 2 S12W57 0070 HSX CSO area: 0170

location: S13W56

13723 2024.06.22
2024.06.23
  15 7 S20W33 0050   DRO

location: S20W29

13726 2024.06.22
2024.06.23
  2 1 S04W55 0004   AXX location: S05W38
13724 2024.06.23 1     S16W56 0060 HSX       SWPC split this off from AR 13722
13728 2024.06.23
2024.06.25
3 6 2 S27W22 0030 CAO HRX

location: S27W24

13727 2024.06.24
2024.06.25
7 19 8 S18W19 0130 CAO CAO area: 0230

location: S18W18

S9830 2024.06.24   4 1 S07W19 0008   BXO  
13729 2024.06.25
2024.06.26
24 64 38 S04W00 0240 FSI FAI

beta-gamma-delta

area: 0490

location: S04W01

13730 2024.06.26
2024.06.27
4 13 9 S17W47 0030 DRO DRI area: 0050

location: S18W45

13731 2024.06.26
2024.06.28
1 9 3 S15E07 0010 AXX CRO area: 0015
S9837 2024.06.27       N09W21            
S9838 2024.06.27   11 2 N23W22 0020   BXO  
S9839 2024.06.27       S26W55            
13732 2024.06.28 4     S18W25 0050 DAO       There are no spots at the location given by SWPC. This used to be a split off of the leading penumbra of AR 13727, but that penumbra has disappeared
S9840 2024.06.28       N27W38            
13733 2024.06.28
2024.06.29
6 10 7 N05W00 0040 DAO DRO

location: N03W01

13734 2024.06.28
2024.06.29
7 29 14 N09E42 0080 EAI FAI location: N08E41

area: 0150

S9843 2024.06.28   3 1 N09W01 0007   BXO  
S9844 2024.06.28       N12W30            
S9845 2024.06.28       S30W10          
13735 2024.06.29
2024.06.29
1 1 1 N17E47 0050 HSX HSX

area: 0090

location: N17E48

S9847 2024.06.29   4   S13E19 0006   BXO  
S9848 2024.06.29       N11W45            
S9849 2024.06.29       S16E04            
S9851 2024.06.30       S40E17          
S9854 2024.07.01   2 1 N23E19 0005   AXX    
S9855 2024.07.01   4 3 S13W36 0010   BXO    
S9856 2024.07.01   3 1 S28E08 0008   BXO    
Total spot count: 62 207 104  
Sunspot number: 192 397 294  (total spot count + 10 * number of spotted regions)
Weighted SN: 120 250 155  (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): 211 218 235  

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  176.4 182.2 160.0 124.4 (-0.9) 8.15
2023.08  153.7 157.6 114.8 124.1 (-0.3) 7.19
2023.09  154.4 156.0 134.2 123.9 (-0.2) 14.26
2023.10  142.8 141.9 99.4 124.8 (+0.9) 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
2024.01 164.6 159.3 123.0 (128.9 projected, -0.5) 5.46
2024.02 172.5 168.3 124.7 (129.4 projected, +0.5) 5.31
2024.03 154.4 152.9 104.9 (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
(current
SC25 peak)
2024.06 184.3 190.2 164.2 (134.9 projected, +1.7) 9.9
2024.07 170.6 (1)   6.2 (2A) / 192 (2B) / 165.0 (2C) (134.8 projected, -0.1) (4.9)
2024.08       (134.3 projected, -0.5)  
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 June 6, 2024

May 2024 easily became the month with the highest sunspot counts during solar cycle 25, and early June has seen no change in that pattern of many spot groups, some of which are large and complex. The next candidate for solar max is still uncertain, however, May 20-21, 2024 has all of the smoothed 365d sunspot numbers as well as the 365d smoothed solar flux signalling a peak on those days.

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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.