Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 1, 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 (June 9, 2024)
Solar cycle Solar cycles 23-25 (June 1, 2024) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (June 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 (June 1, 2024) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (June 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 unsettled levels on June 30, weakly under the influence of a positive polarity coronal hole high speed stream. 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 173.8 - decreasing 12.2 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 December 31, 2023). The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 9.9). Three hour interval K indices: 22123322 (planetary), 22143345 (Boulder), 44235533 (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 23 active regions using 2K resolution (SN: 388) and in 17 active regions using 1K resolution (SN: 266) SDO/HMI images.

Region 13719 [S17W82] was mostly quiet and stable as the spot group rotated to the southwest limb. C1 flares: C1.5 @ 14:02 UT
Region 13720 [S05W67] decayed slowly and quietly.
Region 13721 [N27W40] was quiet and stable.
Region 13722 [S13W42] was mostly quiet and stable. C1 flares: C1.6 @ 13:06 UT
Region 13723 [S21W15] developed slowly and was mostly.  Flare: C1.7 @ 14:36, C1.9 @ 00:06 (on July 1, flare began at 23:55) UT
Region 13726 [S07W31] was quiet and stable.
Region 13727 [S18W05] was mostly quiet and stable.
Region 13728 [S28W10] decayed slowly and was mostly quiet. C1 flares: C1.6 @ 03:05 UT
Region 13729 [S04E13] developed slowly and was mostly quiet. M flares are possible. C1 flares: C1.5 @ 22:45 UT
Region 13730 [S17W33] was quiet and stable.
Region 13731 [S16E22] gained a few spots and was mostly quiet.
Region 13733 [N04E14] decayed slowly and was mostly quiet. C1 flares: C1.8 @ 08:09 UT
Region 13734 [N08E56] displayed no major changes and was considerable less active than during the previous days. C1 flares: C1.5 @ 08:28, C1.5 @ 09:58, C1.4 @ 10:52, C1.7 @ 14:18 UT
Region 13735 [N17E62] was quiet and stable.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9830 [S06W04] was quiet and stable.
S9838 [N24W11] developed slowly and quietly.
S9843 [N10E09] was quiet and stable.
S9845 [S30E03] reemerged with tiny spots.
S9847 [S11E30] was quiet and stable.
New region S9851 [S40E30] emerged with a tiny spot at a high latitude.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.3 04:16   13723 GOES16  
C2.0 04:34   13731 GOES16  
C3.8 06:18   13734 GOES16  
C2.0 07:48   13728 GOES16  
C2.2 15:49   13734 GOES16  
C2.8 21:03   13727 GOES16  
C2.2 22:28   13729 GOES16  
C2.2 23:39   13722 GOES16  

Coronal mass ejections (CMEs)

June 28: A faint partial halo CME was observed during the first hours of the day, the source was likely a C6.6 flare in AR 13730 at 23:47 UT on June 27.
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: 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) couød 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 to fair.

Forecast

The geomagnetic field is expected to be quiet to active on July 1 due to effects from the June 28 CME. Unsettled to major storm conditions are possible on July 2-3 in response to effects related to the June 29 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
13719 2024.06.19
2024.06.19
2 2 1 S16W81 0220 CSO CHO

area: 0400

location: S17W82

13720 2024.06.19
2024.06.19
3 4 1 S05W67 0030 BXO BXO

area: 0008

13725 2024.06.20
2024.06.23
      N18W57         location: N22W55
13721 2024.06.21
2024.06.21
3 10 3 N26W41 0060 HAX CAO area: 0090

location: N27W40

13722 2024.06.21
2024.06.21
1 4 3 S11W43 0080 HSX CSO area: 0190

location: S13W42

13723 2024.06.22
2024.06.23
2 10 6 S20W21 0010 BXO DRO

location: S21W15

area: 0060

13726 2024.06.22
2024.06.23
  7   S04W40 0010   BXO location: S07W31
13724 2024.06.23 1     S15W43 0060 HSX       SWPC split this off from AR 13722
13728 2024.06.23
2024.06.25
5 8 4 S27W09 0060 DAO DAO

location: S27W10

13727 2024.06.24
2024.06.25
5 28 17 S19W02 0220 CAO CSI area: 0290

location: S18W05

S9830 2024.06.24   6 2 S06W04 0013   BXO  
13729 2024.06.25
2024.06.26
12 42 27 S04E14 0200 EAI EAI

beta-gamma

area: 0430

location: S04E13

S9832 2024.06.25       N07W50            
13730 2024.06.26
2024.06.27
1 9 4 S18W33 0010 AXX HRX area: 0025

location: S17W33

13731 2024.06.26
2024.06.28
1 8 4 S16E21 0010 AXX CRO area: 0020
S9835 2024.06.26       N51W57            
S9837 2024.06.27       N09W08            
S9838 2024.06.27   10 4 N24W11 0015   BXO  
S9839 2024.06.27       S26W42            
13732 2024.06.28 4     S19W11 0030 CAO       apparently SWPC has split off the westernmost spots of AR 13727. Magnetically there is no separation
S9840 2024.06.28       N27W25          
13733 2024.06.28
2024.06.29
4 10 8 N05E14 0040 DAO DSO

location: N04E14

area: 0100

13734 2024.06.28
2024.06.29
4 18 8 N08E59 0060 DAO FSI location: N08E56

area: 0170

S9843 2024.06.28   3 1 N10E09 0007   AXX  
S9844 2024.06.28       N12W17            
S9845 2024.06.28   5 2 S30E03 0013   BXO    
13735 2024.06.29
2024.06.29
1 1 1 N17E62 0060 HSX HSX

area: 0090

S9847 2024.06.29   2   S11E30 0004   BXO  
S9848 2024.06.29       N11W32          
S9849 2024.06.29       S16E17          
S9850 2024.06.29       S13W52          
S9851 2024.06.30   1   S40E30 0001   AXX    
Total spot count: 49 188 96  
Sunspot number: 199 388 266  (total spot count + 10 * number of spotted regions)
Weighted SN: 104 247 155  (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): 219 213 213  

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 (128.7 projected, +0.9) 9.60
2024.01 164.6 159.3 123.0 (127.0 projected, -1.7) 5.46
2024.02 172.5 168.3 124.7 (126.2 projected, -0.8) 5.31
2024.03 154.4 152.9 104.9 (125.6 projected, -0.6) 11.03
2024.04 161.3 162.6 136.5 (125.6 projected, -0.0) 9.69
2024.05 187.7
(cycle peak)
191.9 171.7 (SC25 peak) (126.7 projected, +1.1) 23.56
(current
SC25 peak)
2024.06 184.3 (1) 190.2 156.6 (2A/2B) / 164.8 (2C) (125.9 projected, -0.8) (9.9)
2024.07       (124.2 projected, -1.7)  
2024.08       (122.2 projected, -2.0)  
2024.09       (121.0 projected, -1.2)  
2024.10       (119.6 projected, -1.4)  
2024.11       (114.5 projected, -5.1)  
2024.12       (109.1 projected, -5.4)  

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.