Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 20, 2023 at 06:10 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 19, weakly under the influence of effects related to CH1153/CH1154. Solar wind speed at DSCOVR ranged between 392 and 503 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 168.8 - increasing 13.9 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 143.92. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 9.4). Three hour interval K indices: 22212333 (planetary), 23323332 (Boulder), 44223455 (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 18 active regions using 2K resolution (SN: 425) and in 15 active regions using 1K resolution (SN: 259) SDO/HMI images.

Region 13332 [S10W81] was mostly quiet and stable. C1 flares: C1.9 @ 14:00 UT
Region 13333 [S11W31] decayed slowly and quietly.
Region 13334 [N16W02] was quiet and stable.
Region 13335 [S14W06] was mostly unchanged and produced a few C flares. C1 flares: C1.8 @ 05:14, C1.6 @ 16:48 UT
Region 13336 [S21W02] has many tiny spots and was mostly quiet.
Region 13337 [N17E19] was quiet and stable.
Region 13338 [N11E17] decayed slowly and was mostly quiet. C1 flares: C1.8 @ 14:21, C1.7 @ 15:04 UT
Region 13339 [S19E44] was unchanged and quiet.
Region 13340 [N22E45] developed slowly and produced a few C flares. C1 flares: C1.9 @ 07:14 UT
New region 13341 [S14E75] rotated partly into view on June 18 and was numbered by SWPC the next day.
New region 13342 [S22W59] emerged on June 17 with SWPC numbering the region 2 days later. C flares are possible.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S8669 [N16W59] decayed slowly and quietly.
S8676 [S12E56] was quiet and stable.
New region S8679 [N22W32] emerged with several spots.
New region S8680 [S16E39] emerged with tiny spots.
New region S8682 [N17E48] emerged with several spots.
New region S8683 [N09E72] emerged with tiny spots. C1 flares: C1.8 @ 21:49 UT
New region S8684 [S16W34] emerged with tiny spots.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.2 00:25   13340 GOES16  
C2.7 00:44   13340 GOES16  
C2.9 00:54   13335 GOES16  
C6.0 02:08   13338 GOES16  
C6.1 02:14   13340 GOES16  
C2.3 03:30   S8680 GOES16  
C4.3 03:41   13340 GOES16  
M1.4 03:50   13341 GOES16 moderate type II radio sweep
simultaneous flares in ARs 13339 and 13342
C2.8 04:14   13335 GOES16  
C2.3 11:46   11340 GOES16  
M1.1 12:14 S13E79 13341 GOES16 moderate type II radio sweep
C2.1 12:34   13341 GOES16  
C2.2 12:59   13338 GOES16 simultaneous flare in AR 13341
C3.2 16:23 S17E00 13335 GOES16  
C2.4 16:59 S22W60 13342 GOES16  
C2.5 17:19 S18W03 13335 GOES16  
C2.2 18:46 S15E00 13335 GOES16  
C2.4 23:57   13335 GOES16  

Coronal mass ejections (CMEs)

June 16-18: 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 20-21 due to weak effects from CH1153 and CH1154. Quiet conditions are likely on June 22.

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
13332 2023.06.07
2023.06.07
1 5 2 S09W83 0010 AXX CRO

location: S10W81

area: 0020

S8639 2023.06.09       S13W51            
S8646 2023.06.10       S30W36            
S8649 2023.06.10       S20W47            
S8652 2023.06.11       N18W37            
13333 2023.06.12
2023.06.13
12 34 12 S11W31 0090 EAI EAI beta-gamma
13334 2023.06.13
2023.06.13
  21 7 N16W07 0035   BXO

location: N16W02

SWPC added a duplicate region on June 19, AR 13343

13336 2023.06.13
2023.06.14
7 38 11 S23E03 0020 CRO BXI

area: 0070

location: S21W02

13335 2023.06.13
2023.06.14
22 38 24 S15W03 0200 EAI EHI beta-gamma

area: 0340

location: S14W06

S8661 2023.06.14       N22E03            
13337 2023.06.14
2023.06.15
1 8 2 N17E18 0010 AXX CRO location: N17E19
13338 2023.06.14
2023.06.15
10 26 12 N11E17 0070 DAO EAO

area: 0100

S8667 2023.06.15       N27W43            
S8669 2023.06.16   1   N16W59 0001   AXX  
S8670 2023.06.16       N07E26            
13339 2023.06.16
2023.06.17
1 1 1 S19E42 0180 HSX HHX area: 0270

location: S19E44

S8672 2023.06.17       N20W51            
13340 2023.06.17 6 21 10 N23E45 0100 DAO DAO   area: 0160
S8674 2023.06.17       S23W45            
13342 2023.06.17
2023.06.19
5 20 9 S22W60 0060 DAO DAI area: 0110
S8676 2023.06.18   3   S12E56 0004   BXO  
13341 2023.06.18
2023.06.19
2 5 4 S13E62 0100 CSO DSO location: S14E75

area: 0290

S8678 2023.06.18       S01W01          
13343 2023.06.19 4     N16W01 0010 BXO       this is a duplicate of AR 13334
S8679 2023.06.19   8 5 N22W32 0020   BXO    
S8680 2023.06.19   3 2 S16E39 0007   BXO    
S8681 2023.06.19       N49W49          
S8682 2023.06.19   8 5 N17E48 0040   DRO    
S8683 2023.06.19   3 3 N09E72 0008   BXO    
S8684 2023.06.19   2   S16W34 0003   BXO    
Total spot count: 71 245 109  
Sunspot number: 181 425 259  (total spot count + 10 * number of spotted regions)
Weighted SN: 109 299 163  (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): 199 234 207  

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
2023.06 160.6 (1)   82.8 (2A) / 130.7 (2B) / 166.7 (2C) (134.3 projected, +3.1) (8.1)
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.