Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 13, 2024 at 04:10 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 (March 3, 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 June 12. The high latitude magnetometer at Andenes recorded quiet to active levels. The above 10 MeV proton flux was at 8 pfu at the end of the day.

Solar flux density measured at 20h UT on 2.8 GHz was 164.9 - decreasing 42.3 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 162.02. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 162.02 on December 13, 2023). The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.1). Three hour interval K indices: 11111112 (planetary), 11221322 (Boulder), 01113244 (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 14 active regions using 2K resolution (SN: 286) and in 12 active regions using 1K resolution (SN: 192) SDO/HMI images.

Region 13702 [N17W62] decayed slowly and quietly.
Region 13707 [S14W19] decayed slowly and was mostly quiet.
Region 13708 [S21W04] was quiet and stable.
Region 13709 [S09E01] was mostly quiet and stable.
Region 13711 [S10E14] decayed slowly and produced the only M flare of the day.
New region 13712 [S24E52] emerged quickly on June 11 and developed further the next day when it was numbered by SWPC. C1 flares: C1.8 @ 04:31, C1.6 @ 08:11, C1.6 @ 08:46, C1.6 @ 09:17 UT
New region 13713 [S13E70] rotated into view on June 11 and received its NOAA number the following day. C1 flares: C1.9 @ 12:34 UT
New region 13714 [N14E26] was first observed with spots on June 8. Slow development was observed on June 12 when SWPC numbered the spot group.
New region 13715 [N17E49] emerged on June 11 with SWPC numbering the region the next day.
New region 13716 [N10E62] emerged with a few spots.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9778 [N18W35] decayed slowly and quietly.
S9781 [S22W18] was quiet and stable.
S9789 [N18W08] reemerged with tiny spots.
S9796 [N22E14] was quiet and stable.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.2 01:11   13710 GOES16  
C2.1 05:09   13711 GOES16  
C3.6 05:21   13713 GOES16  
C2.3 05:52   13709 GOES16  
C2.7 07:28   13712 GOES16  
C2.0 10:26   13713 GOES16  
C4.4 13:07   13713 GOES16  
C2.5 14:55   13710 GOES16  
C3.3 15:24   13709 GOES16  
C3.4 16:26   13712 GOES16  
C4.2 17:33   13710 GOES16 simultaneous flare in AR 13712
C4.5 20:52   13709 GOES16  
M1.2 22:46   13711 GOES16  

Coronal mass ejections (CMEs)

June 10-12: No obviously Earth directed CME 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 southern hemisphere negative polarity coronal hole (CH1225) would have been Earth facing on June 10. CH1225 apparently closed before rotating across the central meridian. A positive polarity trans equatorial coronal hole (CH1226) will likely become Earth facing on June 13-14. A positive polarity northern hemisphere coronal hole (CH1227) rotated across the central meridian on June 12.

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 unsettled on June 13-15.

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
13702 2024.06.01
2024.06.02
2 3 1 N17W63 0050 CSO CSO

area: 0130

location: N17W62

13704 2024.06.02
2024.06.03
      S18W60            
13706 2024.06.03
2024.06.04
      S12W83            
S9769 2024.06.03       N09W50            
S9774 2024.06.05       S27W39            
13707 2024.06.05
2024.06.06
4 23 8 S14W19 0010 CAO CRI

area: 0040

13708 2024.06.05
2024.06.06
2 8 6 S21W05 0040 HAX DAO area: 0080

location: S21W04

S9778 2024.06.06   3   N18W35 0004   BXO  
13709 2024.06.06
2024.06.07
9 37 18 S10E02 0140 CAI CAI area: 0280

location: S09E01

S9781 2024.06.07   7 2 S22W18 0015   BXO  
S9782 2024.06.07       S09W07            
13711 2024.06.07
2024.06.09
3 10 6 S09E12 0010 BXO DRO beta-gamma

location: S10E14

area: 0025

13714 2024.06.08
2024.06.12
5 10 5 N14E24 0010   BXO location: N14E26
S9786 2024.06.08       S23W37          
S9789 2024.06.09   2 1 N18W08 0007   AXX    
S9791 2024.06.10       S24E07            
13715 2024.06.11
2024.06.12
3 7 3 N17E49 0010 BXO BXO area: 0015
13712 2024.06.11
2024.06.12
11 22 15 S24E52 0180 DAO DAI area: 0320
S9794 2024.06.11       S15E66           part of AR 13713
13713 2024.06.11
2024.06.12
3 5 4 S13E68 0150 DSO DSO location: S13E70

area: 0300

S9796 2024.06.11   3   N27E35 0004   BXO  
S9797 2024.06.11       S04W31          
S9798 2024.06.11       S20E20          
13716 2024.06.12 3 6 3 N10E62 0020 CRO DRO   area: 0040
Total spot count: 45 146 72  
Sunspot number: 145 286 192  (total spot count + 10 * number of spotted regions)
Weighted SN: 78 180 106  (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): 160 157 154  

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)
2024.06 183.0 (1)   65.6 (2A) / 163.9 (2B) / 170.9 (2C) (125.9 projected, -0.8) (8.8)
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.