Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 27, 2023 at 06:05 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 unsettled on June 26 due to weak CME effects. Solar wind speed at SOHO ranged between 499 and 654 km/sec. The high latitude magnetometer at Andenes recorded quiet to minor storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 157.7 - decreasing 4.3 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 144.83. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.1). Three hour interval K indices: 23223323 (planetary), 32333333 (Boulder), 43234524 (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 13 active regions using 2K resolution (SN: 303) and in 12 active regions using 1K resolution (SN: 213) SDO/HMI images.

Region 13337 [N21W75] decayed slowly and was mostly quiet.
Region 13338 [N11W79] decayed slowly and quietly.
Region 13339 [S19W50] was mostly quiet and stable.
Region 13340 [N23W44] still has a complex magnetic layout in the trailing spot section and could produce further M class events. Some decay was observed in the leading spot section.
Region 13341 [S15W19] decayed significantly and was mostly quiet. C1 flares: C1.3 @ 00:33, C1.3 @ 03:25, C1.1 @ 07:45, C1.2 @ 08:30, C1.1 @ 09:17, C1.8 @ 17:19. C1.9 @ 17:24, C1.5 @ 20:30, C1.6 @ 22:45, C1.7 @ 23:04 UT
Region 13345 [N08W22] decayed slowly and quietly.
Region 13346 [N09W46] was quiet and stable.
Region 13348 [S31E11] was quiet and developed slowly.
Region 13349 [N09W02] was quiet and stable.
Region 13350 [S14E01] reemerged with tiny spots. C1 flares: C1.7 @ 05:13 UT
Region 13351 [N22E19] developed slowly and quietly. C1 flares: C1.3 @ 03:16, C1.2 @ 07:07 UT
New region 13354 [N14E27] rotated into view on June 22 with tiny spots. The region developed quickly on June 26 as new flux emerged. A minor M class flare is possible.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
New region S8706 [S14E76] rotated into view with a mature spot.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.1 00:56 S20W33 13339 GOES16  
C2.2 01:36 N25W33 13340 GOES16  
C2.1 02:30 N23W30 13340 GOES16  
C7.0/1F 04:02 N23W31 13340 GOES16  
C3.0/1F 06:32 N22W34 13340 GOES16  
C2.9 11:52   13351 GOES16  
C2.0 12:07   13337 GOES16  
C7.5 12:25   13340 GOES16  
M1.6 16:22 N23W38 13340 GOES16  
M1.1 16:27   13340 GOES16  
C4.0 16:43   13340 GOES16  
C2.1 19:28   13354 GOES16  
C3.4 19:56 N25W40 13340 GOES16  
C2.3 22:21 N25W40 13340 GOES16  
C3.6 23:20   13340 GOES16  
C2.2 23:46   13340 GOES16  

Coronal mass ejections (CMEs)

June 24-26: 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, trans equatorial coronal hole (CH1155) was Earth facing on June 23-24. 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. Propagation on long distance northeast-southwest paths is poor.

Forecast

Quiet to unsettled conditions are expected for June 27-28 with a chance of active intervals due to effects from CH1155.

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
13337 2023.06.14
2023.06.15
1 1 1 N15W75 0010 HRX HRX location: N21W75
13338 2023.06.14
2023.06.15
2 2 1 N09W78 0010 AXX AXX

location: N11W79

13339 2023.06.16
2023.06.17
10 16 7 S23W51 0150 CSO CSO

location: S19W50

area: 0100

13340 2023.06.17 22 50 29 N20W45 0350 EKI DAC beta-gamma-delta

location: N23W44

S8676 2023.06.18       S13W48            
13341 2023.06.18
2023.06.19
9 28 15 S15W19 0120 CAO CAO

 

S8680 2023.06.19       S16W52            
S8682 2023.06.19       N15W46          
13345 2023.06.19
2023.06.20
1 2 1 N09W23 0010 HRX HRX

area: 0030

13346 2023.06.20
2023.06.21
  2   N08W47 0004   AXX location: N09W46
13350 2023.06.20
2023.06.23
  4 2 S11W03 0008   AXX   location: S14E01
S8687 2023.06.20       N31W28            
S8689 2023.06.21       N15W01            
13347 2023.06.21
2023.06.23
1     S19W64 0010 AXX     spotless
13348 2023.06.21
2023.06.23
2 10 5 S33E07 0010 BXO CRO location: S31E11

area: 0030

13349 2023.06.22
2023.06.23
  1 1 N08W03 0003   AXX location: N09W02
13351 2023.06.22
2023.06.23
5 17 7 N20E18 0030 CRO DRO location: N22E19
S8695 2023.06.22       N16W20            
S8697 2023.06.22       S14W52            
S8698 2023.06.22       N37W25            
13354 2023.06.22
2023.06.26
5 39 23 N15E24 0020 CSO DAI area: 0200
13352 2023.06.23
2023.06.24
      N09W87          
S8701 2023.06.23       S11W45            
S8702 2023.06.23       N38W51            
13353 2023.06.24       S18W40           location is inside the trailing spot section of AR 13339
S8704 2023.06.24       N08E06            
S8705 2023.06.25       N30W10          
S8706 2023.06.26   1 1 S14E76 0120   HSX    
Total spot count: 58 173 93  
Sunspot number: 158 303 213  (total spot count + 10 * number of spotted regions)
Weighted SN: 92 210 130  (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): 174 167 170  

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
2023.06 162.5 (1)   124.5 (2A) / 143.7 (2B) / 180.8 (2C) (134.3 projected, +3.1) (8.5)
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.