Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 23, 2023 at 05:55 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 22. Solar wind speed at SOHO ranged between 389 and 459 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 173.2 - increasing 24.2 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 144.27. 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: 12222221 (planetary), 12322313 (Boulder), 32224454 (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 23 active regions using 2K resolution (SN: 494) and in 21 active regions using 1K resolution (SN: 332) SDO/HMI images.

Region 13333 [S09W76] decayed slowly and quietly.
Region 13334 [N17W38] decayed slowly and quietly.
Region 13335 [S15W47] was mostly quiet and stable.
Region 13337 [N19W23] developed slowly and produced a few flares before noon. A weak magnetic delta is in the leading penumbra.
Region 13338 [N11W23] decayed slowly and quietly.
Region 13339 [S20E04] developed slowly and was mostly quiet.
Region 13340 [N22E07] developed further and could produce M class flares.
Region 13341 [S16E36] was again the main source of activity on the visible disk. The CME associated with an M4 flare near the end of the day may have Earth directed components. LASCO imagery was missing for several hours which makes a more definite forecast difficult.
Region 13344 [N23W72] was quiet and stable.
Region 13345 [N08E32] was quiet and stable.
Region 13346 [N08E09] was quiet and stable.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S8682 [N18E07] developed slowly and quietly.
S8686 [S12E53] was quiet and stable.
S8687 [N25E19] was quiet and stable.
S8688 [S27W11] was quiet and stable.
S8690 [S19W12] developed slowly and quietly.
S8692 [S31E61] developed slowly and quietly.
New region S8693 [N09E52] emerged with a few spots.
New region S8694 [N22E74] rotated into view with small spots.
New region S8695 [N16E32] emerged with tiny spots in an old plage area.
New region S8697 [S14W00] emerged with a tiny spot.
New region S8698 [N37E27] emerged with a tiny spot.
New region S8699 [N14E76] rotated into view with a tiny spot.

AR 13342 behind the southwest limb produced a C1.8 flare at 02:59 UT

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C6.2 01:10 N20W09 13337 GOES16  
C2.0 02:18   13342 GOES16  
C3.4 03:42 behind northeast limb   GOES16 LDE
C3.8 04:10 behind southwest limb 13342 GOES16  
C3.9 04:37   13341 GOES16  
C3.3 05:45   13342 GOES16  
C4.0 06:13   13337 GOES16  
C4.1 08:24 N19W12 13337 GOES16  
C2.0 09:59 behind southwest limb 13342 GOES16  
C2.1 10:50 northeast limb S8699? GOES16  
M1.1/1N 11:21 S12E44 13341 GOES16  
C2.9 13:30 S17E45 13341 GOES16  
C3.3 13:46 S09E43 13341 GOES16  
C2.9 16:16   13339 GOES16  
C3.1 16:32 |northeast limb   GOES16  
C2.9 17:43   13337 GOES16  
M4.8 23:44   13341 GOES16 moderate type II and weak type IV radio sweeps. CME

Coronal mass ejections (CMEs)

June 22: A CME was observed after the M4 flare in AR 13341 late in the day. Any Earth directed components would likely reach us on June 26.
June 21
: No obviously Earth directed CMEs were observed.
June 20: A CME associated with X1 flare at 17:09 UT in AR 13341 may have Earth directed components. In that case a weak shock and unsettled to minor storm intervals are possible on June 23-24.

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 trans equatorial coronal hole (CH1155) could become Earth facing on June 23. CH1155 lost a substantial part of its area on June 21 due to the development of AR 13346.

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 geomagnetic conditions are expected for June 23-25 with a chance of active to minor storm conditions on June 23-24 if the June 20 CME arrives.

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
13333 2023.06.12
2023.06.13
5 2 1 S11W71 0030 CAO HRX location: S09W76
13334 2023.06.13
2023.06.13
3 12 3 N17W40 0020 BXO BXO

location: N17W38

SWPC added a duplicate region on June 19, AR 13343

13336 2023.06.13
2023.06.14
      S19W44          

location: S21W42

northern part merged with AR 13335 on June 21

13335 2023.06.13
2023.06.14
9 30 11 S15W44 0230 ESI DKI

area: 0310

location: S15W47

S8661 2023.06.14       N22W36            
13337 2023.06.14
2023.06.15
6 22 11 N20W24 0060 DRO DAO beta-gamma-delta

location: N19W23

area: 0120

13338 2023.06.14
2023.06.15
4 10 4 N11W22 0030 CSO CAO

area: 0080

location: N11W23

S8670 2023.06.16       N07W13            
13339 2023.06.16
2023.06.17
9 31 14 S20E03 0140 CAO DAI area: 0200

location: S20E04

13340 2023.06.17 12 44 24 N22E07 0130 DSI DAI   beta-gamma

area: 0230

S8676 2023.06.18       S13E17            
13341 2023.06.18
2023.06.19
7 28 11 S16E35 0180 CSO CSO beta-gamma

location: S16E36

area: 0270

S8678 2023.06.18       S01W40            
13343 2023.06.19       N16W40           this is a duplicate of AR 13334
13344 2023.06.19
2023.06.20
2 3 2 N23W73 0040 DAO DAO location: N23W72
S8680 2023.06.19       S16W00            
S8682 2023.06.19   9 7 N18E07 0025   CRO  
13345 2023.06.19
2023.06.20
5 14 5 N09E33 0040 CSO DRI location: N08E32
13346 2023.06.20
2023.06.21
4 10 3 N08E08 0020 BXO DRO location: N08E07
S8686 2023.06.20   4 1 S12E53 0010   HRX  
S8687 2023.06.20   2 1 N25E19 0004   AXX  
S8688 2023.06.21   9 5 S27W12 0015   AXX  
S8689 2023.06.21       N15E51          
S8690 2023.06.21   13 9 S19W12 0050   DRI  
S8691 2023.06.21       S07W33          
S8692 2023.06.21   7 3 S31E61 0020   CRO  
S8693 2023.06.22   7 3 N09E52 0060   DRO    
S8694 2023.06.22   2 1 N22E74 0030   HAX    
S8695 2023.06.22   2 2 N16E32 0006   AXX    
S8697 2023.06.22   1 1 S14W00 0002   AXX    
S8698 2023.06.22   1   N37E27 0001   AXX    
S8699 2023.06.22   1   N14E76 0001   AXX    
Total spot count: 66 264 122  
Sunspot number: 176 494 332  (total spot count + 10 * number of spotted regions)
Weighted SN: 109 333 191  (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): 194 272 266  

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
2023.06 162.8 (1)   100.1 (2A) / 136.5 (2B) / 175.3 (2C) (134.3 projected, +3.1) (7.9)
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.