Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 18, 2023 at 09:55 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 on June 17, weakly under the influence of effects related to CH1153. Solar wind speed at SOHO ranged between 500 and 673 km/sec. The high latitude magnetometer at Andenes recorded quiet to active levels.

Solar flux density measured at 20h UT on 2.8 GHz was 158.1 - decreasing 5.3 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 143.78. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 7 (STAR Ap - based on the mean of three hour interval ap indices: 6.9). Three hour interval K indices: 22222222 (planetary), 23222322 (Boulder), 44323343 (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: 318) and in 12 active regions using 1K resolution (SN: 219) SDO/HMI images.

Region 13331 [S23W65] decayed slowly and was mostly quiet. C1 flares: C1.5 @ 06:10 UT
Region 13332 [S11W53] reemerged with tiny spots.
Region 13333 [S11W05] was mostly quiet and stable. The region could produce a minor M class flare. C1 flares: C1.3 @ 03:01 UT
Region 13334 [N16E26] was quiet and stable.
Region 13335 [S14E21] still has a magnetic delta configuration in the leading spot section. M class flares are possible. C1 flares: C1.7 @ 01:39, C1.7 @ 13:26, C1.3 @ 19:34 UT
Region 13336 [S21E29] decayed slowly and was mostly quiet. C1 flares: C1.8 @ 08:20, C1.2 @ 09:26 UT
Region 13338 [N11E43] developed slowly and was mostly quiet. C1 flares: C1.4 @ 02:20, C1.8 @ 14:04 UT
New region 13339 [S19E70] rotated into view on June 16 with SWPC numbering the region the next day. C1 flares: C1.9 @ 13:19, C1.8 @ 15:38, C1.4 @ 19:42, C1.6 @ 22:01 UT

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S8669 [N16W32] was quiet and stable.
New region S8672 [N20W25] emerged with a tiny spot.
New region S8673 [N23E73] emerged with tiny spots. C1 flares: C1.5 @ 05:48, C1.9 @ 16:39, C1.6 @ 18:23 UT
New region S8674 [S23W19] emerged with a tiny spot.
New region S8675 [S21W32] emerged with tiny spots.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.0 10:58   13339 GOES16 LDE
C2.0 12:51   13335 GOES16  
C2.2 15:21   13333 GOES16  
C2.2 16:14   13339 GOES16  
C4.4 16:57   13335 GOES16  
C2.0 17:37   13335 GOES16  
C2.1 23:54   13339 GOES16  

Coronal mass ejections (CMEs)

June 15-17: 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 recurrent trans equatorial coronal hole (CH1153) rotated across the central meridian on June 12-17. A southern hemisphere coronal hole (CH1154) was Earth facing on June 16-17, however, CH1154 closed on June 17.

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

Quiet to unsettled geomagnetic conditions are expected for June 18-20 due to weak effects from CH1153 and then CH1154.

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
13331 2023.06.06
2023.06.07
2 3 2 S23W66 0060 HSX HAX

location: S23W65

13332 2023.06.07
2023.06.07
  2 2 S10W59 0010   HRX  

location: S11W53

S8639 2023.06.09       S13W25          
S8646 2023.06.10       S30W10          
S8649 2023.06.10       S20W21            
S8651 2023.06.11       S12W38            
S8652 2023.06.11       N18W11            
13333 2023.06.12
2023.06.13
18 40 25 S11W05 0240 EAI EAI  
13334 2023.06.13
2023.06.13
  25 6 N16E21 0035   BXO

location: N16E26

area: 0020

13336 2023.06.13
2023.06.14
5 27 12 S21E31 0030 CRO CRI

area: 0070

location: S21E29

S8657 2023.06.13       N20W56            
13335 2023.06.13
2023.06.14
18 51 29 S15E24 0390 EKI EKC beta-gamma-delta

area: 0470

location: S15E36

S8660 2023.06.14       S20W48            
S8661 2023.06.14       N22E29            
13337 2023.06.14
2023.06.15
      N17E45         location: N18E45
13338 2023.06.14
2023.06.15
6 21 12 N11E45 0130 CSO EAO

area: 0270

location: N11E43

S8664 2023.06.14       S10W51            
S8665 2023.06.15       S13W21          
S8666 2023.06.15       N26W59          
S8667 2023.06.15       N27W17            
S8668 2023.06.15       N17W43          
S8669 2023.06.16   5 4 N16W32 0015   BXO  
S8670 2023.06.16       N07E52          
13339 2023.06.16
2023.06.17
1 1 1 S19E70 0100 HSX HHX area: 0250
S8672 2023.06.17   1 1 N20W25 0003   AXX    
S8673 2023.06.17   8 4 N23E73 0030   CRI    
S8674 2023.06.17   1 1 S23W19 0004   AXX    
S8675 2023.06.17   3   S21W32 0003   BXO    
Total spot count: 50 188 99  
Sunspot number: 110 318 219  (total spot count + 10 * number of spotted regions)
Weighted SN: 78 232 143  (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): 121 175 175  

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
2023.06 160.0 (1)   72.3 (2A) / 127.6 (2B) / 163.7 (2C) (134.3 projected, +3.1) (8.0)
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.