Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 26, 2023 at 02:50 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 minor storm on June 25 under the influence of CME effects. Solar wind speed at SOHO ranged between 477 and 582 km/sec. The high latitude magnetometer at Andenes recorded quiet to major storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 154.8 - increasing 0.4 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 144.67. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 15 (STAR Ap - based on the mean of three hour interval ap indices: 15.3). Three hour interval K indices: 52212343 (planetary), 53213323 (Boulder), 63223455 (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 16 active regions using 2K resolution (SN: 319) and in 13 active regions using 1K resolution (SN: 207) SDO/HMI images.

Region 13335 [S14W86] produced a few flares as it rotated mostly out of view.
Region 13337 [N21W61] decayed slowly and produced a few flares.
Region 13338 [N11W66] decayed slowly and was mostly quiet. C1 flares: C1.7 @ 23:17 UT
Region 13339 [S19W37] was mostly quiet and stable.
Region 13340 [N23W31] developed further and has M class flare potential. C1 flares: C1.6 @ 01:44, C1.3 @ 03:30, C1.6 @ 10:07, C1.9 @ 11:08, C1.7 @ 17:23, C1.9 @ 20:02, C1.6 @ 23:01 UT
Region 13341 [S15W05] produced the largest flare of the day. C1 flares: C1.3 @ 08:43 UT
Region 13345 [N09W09] was quiet and stable.
Region 13346 [N09W34] decayed and could soon become spotless.
Region 13347 [S18W50] decayed slowly and quietly.
Region 13348 [S31E24] developed slowly and quietly.
Region 13349 [N09E11] decayed slowly and quietly.
Region 13351 [N22E32] gained several spots as the former single spot split into smaller penumbrae.
Region 13352 [N09W72] decayed slowly and quietly.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S8682 [N15W33] was quiet and stable.
S8699 [N17E38] was quiet and stable.
New region S8705 [N30E03] emerged with a tiny spot.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.3 02:19   13339 GOES16  
C2.7 04:22   13335 GOES16  
C2.0 05:49   13340 GOES16  
C6.0 07:08 S16W77 13335 GOES16  
C8.5/1N 12:18 S18E05 13341 GOES16  
C2.1 17:39   13340 GOES16  
C2.2 17:49   13340 GOES16  
C4.5 20:28   13337 GOES16  
C2.4 21:30   13335 GOES16  
C3.0 21:42   13341 GOES16 simultaneous flare in AR 13346
C6.8 22:02 N21W63 13337 GOES16  

Coronal mass ejections (CMEs)

June 23-25: 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.

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 26 due to weakening CME effects. Effects from CH1155 could reach Earth on June 27-28 and cause a few unsettled and active intervals.

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
13334 2023.06.13
2023.06.13
      N17W82          

location: N18W76

SWPC added a duplicate region on June 19, AR 13343

13336 2023.06.13
2023.06.14
      S19W86          

location: S21W81

northern part merged with AR 13335 on June 21

13335 2023.06.13
2023.06.14
1 2   S15W87 0200 HAX CSO  
13337 2023.06.14
2023.06.15
3 6 3 N21W61 0030 HAX CRO  
13338 2023.06.14
2023.06.15
3 8 5 N11W64 0020 CRO DRO

location: N11W66

S8670 2023.06.16       N07W52            
13339 2023.06.16
2023.06.17
6 26 14 S20W37 0090 CSO CSI

location: S19W37

13340 2023.06.17 18 37 25 N23W31 0300 EKC DKC beta-gamma-delta

area: 0480

S8676 2023.06.18       S13W22            
13341 2023.06.18
2023.06.19
5 33 8 S16W05 0130 CAO CSO

area: 0220

13343 2023.06.19       N16W84           this is a duplicate of AR 13334
S8680 2023.06.19       S16W39            
S8682 2023.06.19   7 3 N15W33 0012   CRO  
13345 2023.06.19
2023.06.20
1 7 3 N09W09 0010 HRX CRO

area: 0030

13346 2023.06.20
2023.06.21
2 3   N08W33 0010 BXO AXX location: N09W34

area: 0004

13350 2023.06.20
2023.06.23
      S11E11          
S8687 2023.06.20       N31W15            
S8688 2023.06.21       S28W50            
S8689 2023.06.21       N15E12            
13347 2023.06.21
2023.06.23
2 3 2 S18W50 0010 AXX AXX  
13348 2023.06.21
2023.06.23
  6 5 S31E20 0015 BXO BXO location: S31E24
13349 2023.06.22
2023.06.23
2 2   N08E11 0010 BXO BXO location: N09E11

area: 0003

13351 2023.06.22
2023.06.23
3 10 5 N22E32 0020 HRX CRO area: 0035
S8695 2023.06.22       N16W07            
S8697 2023.06.22       S14W39            
S8698 2023.06.22       N37W12            
S8699 2023.06.22   5 2 N17E38 0010   BXO  
13352 2023.06.23
2023.06.24
3 3 1 N09W73 0010 BXO BXO area: 0006
S8701 2023.06.23       S11W32            
S8702 2023.06.23       N38W38            
13353 2023.06.24 1     S18W26 0010 AXX       location is inside the trailing spot section of AR 13339
S8704 2023.06.24       N08E19          
S8705 2023.06.25   1 1 N30E03 0003   AXX    
Total spot count: 50 159 77  
Sunspot number: 180 319 207  (total spot count + 10 * number of spotted regions)
Weighted SN: 89 199 117  (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): 198 175 166  

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
2023.06 162.7 (1)   119.3 (2A) / 143.1 (2B) / 180.6 (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.