Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 30, 2023 at 05:15 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 1, 2023)
Solar cycle Solar cycles 23-25 (June 1, 2023) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (June 1, 2023) 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, 2023) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (June 1, 2023) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (May 29, 2023) 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

Recent activity

The geomagnetic field was quiet to active on June 29, most likely under the influence of effects from CH1156. Solar wind speed at SOHO ranged between 414 and 507 km/sec. The high latitude magnetometer at Andenes recorded unsettled to minor storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 162.2 - decreasing 0.1 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 145.33. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 17 (STAR Ap - based on the mean of three hour interval ap indices: 17.1). Three hour interval K indices: 33332444 (planetary), 33333433 (Boulder), 45353445 (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 12 active regions using 2K resolution (SN: 242) and in 10 active regions using 1K resolution (SN: 166) SDO/HMI images.

Region 13340 [N25W79] decayed and was quiet as it began to rotate over the northwest limb.
Region 13341 [S16W59] decayed further and was mostly quiet.
Region 13345 [N08W62] was quiet and stable.
Region 13348 [S32W28] decayed slowly and was mostly quiet.
Region 13351 [N22W21] decayed slowly and could soon become spotless.
Region 13354 [N14W14] changed significantly with the main penumbral area splitting into smaller penumbra. Some area was lost in the trailing spot section. There are still a few minor magnetic delta structures and an X class flare is possible. C1 flares: C1.1 @ 00:20, C1.7 @ 02:57, C1.9 @ 03:10, C1.4 @ 04:57, C1.2 @ 05:10, C1.0 @ 06:33, C1.1 @ 06:44, C1.4 @ 07:23, C1.1 @ 09:28, C1.1 @ 10:18 UT
Region 13355 [S16E36] lost area and gained small and tiny spots.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
New region S8709 [N14W62] emerged with tiny spots and was split from AR 13345.
New region S8710 [S07E53] emerged with tiny spots.
New region S8711 [N14E49] emerged with a tiny spot.
New region S8712 [S12E22] emerged with tiny spots.
New region S8713 [S12E11] was observed with tiny spots in an old plage area.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.8 04:03 S32W20 13348 GOES16  
C3.3 04:20 S15W56 13341 GOES16  
C2.7 08:09 N14W01 13354 GOES16  
C3.4 11:15 N14W11 13354 GOES16  
C2.4 11:53   13354 GOES16  
C3.2 12:38 N14W11 13354 GOES16  
M3.8/2B 14:15 N17W14 13354 GOES16  
C2.5 16:37   13354 GOES16  
C3.3 18:09   13339 GOES16  
C2.8 18:36   13354 GOES16  
C2.7 18:46   13354 GOES16  
C3.0 20:13   S8709 GOES16 incorrectly attributed to AR 13340 by SWPC
C5.3 22:07   13354 GOES16  
C2.6 22:47   13354 GOES16  

Coronal mass ejections (CMEs)

June 27-29: No obviously Earth directed CMEs were 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 small southern hemisphere coronal hole (CH1156) rotated across the central meridian on June 26-27.

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 to fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

Quiet to unsettled conditions are expected for June 30 due to effects from CH1156. Quiet conditions are likely on July 1-2.

Coronal holes (1) Coronal mass ejection (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
13339 2023.06.16
2023.06.17
1     S19W91 0030 HAX    

rotated out of view

13340 2023.06.17 7 5 3 N23W86 0080 EAI BXO

location: N25W79

area: 0020

13341 2023.06.18
2023.06.19
2 3 2 S15W61 0020 HAX CRO

location: S16W59

13345 2023.06.19
2023.06.20
1 1 1 N09W64 0010 AXX AXX

 

13346 2023.06.20
2023.06.21
      N08W89           location: N09W85
13350 2023.06.20
2023.06.23
      S11W45           location: S09W40
S8689 2023.06.21       N15W40            
13348 2023.06.21
2023.06.23
  2   S33W33 0003   BXO location: S32W28
13349 2023.06.22
2023.06.23
      N08W45         location: N09W41
13351 2023.06.22
2023.06.23
  3 1 N21W22 0005   AXX location: N22W21
S8695 2023.06.22       N16W59            
13354 2023.06.22
2023.06.26
40 89 48 N15W16 0890 EKC FKC beta-gamma-delta

area: 1090

location: N14W14

13353 2023.06.24       S18W82           location is inside the trailing spot section of AR 13339
S8704 2023.06.24       N08W33            
S8705 2023.06.25       N29W47            
13355 2023.06.26
2023.06.27
1 6 4 S16E28 0030 HAX CAO area: 0060

location: S16E36

S8707 2023.06.27       N20E05            
S8709 2023.06.29   6 4 N14W62 0015   BXO    
S8710 2023.06.29   2 1 S07E53 0010   AXX    
S8711 2023.06.29   1 1 N14E49 0004   AXX    
S8712 2023.06.29   2 1 S12E22 0005   BXO    
S8713 2023.06.29   2   S12E11 0003   AXX    
Total spot count: 52 122 66  
Sunspot number: 112 242 166  (total spot count + 10 * number of spotted regions)
Weighted SN: 82 140 84  (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): 123 133 133  

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
2021.10 88.9 88.3 37.4 45.2 (+5.0) 7.38
2021.11 86.2 84.4 34.8 50.8 (+5.6) 9.83
2021.12 103.0 99.8 67.5 55.9 (+5.1) 6.40
2022.01 103.8 100.5 55.3 60.1 (+4.2) 8.92
2022.02 109.1 106.5 60.9 64.7 (+4.6) 10.46
2022.03 117.0 115.8 78.6 68.7 (+4.0) 10.20
2022.04 130.8 131.7 84.0 73.0 (+4.3) 11.79
2022.05 133.8 136.8 96.5 77.4 (+4.4) 7.48
2022.06 116.1 119.8 70.3 81.1 (+3.7) 8.20
2022.07 125.4 129.5 91.4 86.7 (+5.6) 9.51
2022.08 114.2 117.1 74.6 92.5 (+5.8) 10.92
2022.09 135.1 136.5 96.0 96.4 (+3.9) 12.18
2022.10 133.5 132.7 95.5 98.7 (+2.3) 11.16
2022.11 123.4 120.7 80.5 101.0 (+2.3) 9.33
2022.12 147.9 143.4 112.8 (105.8 projected, +4.8) 10.99
2023.01 182.4 176.6 143.6 (112.2 projected, +6.4) 8.73
2023.02 167.2 163.2 110.9 (117.0 projected, +4.8) 14.48
(current
SC25 peak)
2023.03 157.2 155.6 122.6 (120.1 projected, +3.1) 14.42
2023.04 145.4 146.4 96.4 (125.5 projected, +5.4) 13.40
2023.05 155.6 159.2 137.9 (131.2 projected, +5.7) 10.67
2023.06 161.8 (1)   137.7 (2A) / 142.4 (2B) / 175.8 (2C) (134.3 projected, +3.1) (8.4)
2023.07       (133.8 projected, -0.5)  
2023.08       (134.8 projected, +1.0)  
2023.09       (138.2 projected, +3.4)  
2023.10       (140.1 projected, +1.9)  
2023.11       (142.7 projected max SC25)  
2023.12       (142.6 projected, -0.1)  

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

 

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.