Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 25, 2023 at 08:00 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 active on June 24 under the influence of effects from the June 20 CME. Solar wind speed at SOHO ranged between 414 and 572 km/sec. The high latitude magnetometer at Andenes recorded unsettled to minor storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 160.8 - increasing 9.5 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 144.54. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 14 (STAR Ap - based on the mean of three hour interval ap indices: 13.8). Three hour interval K indices: 13323334 (planetary), 23223434 (Boulder), 34434445 (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: 382) and in 18 active regions using 1K resolution (SN: 276) SDO/HMI images.

Region 13335 [S14W74] decayed slowly and was mostly quiet. C1 flares: C1.3 @ 00:05, C1.7 @ 09:31, C1.6 @ 09:50, C1.8 @ 11:35, C1.6 @ 14:35, C1.6 @ 16:33, C1.7 @ 20:21, C1.6 @ 20:39, C1.2 @ 22:24, C1.5 @ 23:58 UT
Region 13337 [N21W48] decayed slowly and produced several flares. C1 flares: C1.4 @ 00:48, C1.7 @ 08:32 UT
Region 13338 [N11W51] was mostly quiet and stable.
Region 13339 [S19W23] was mostly quiet and stable. C1 flares: C1.6 @ 06:46 UT
Region 13340 [N23W18] developed and could produce M flares. The trailing spot section is complex with polarity intermixing. C1 flares: C1.8 @ 04:42, C1.9 @ 10:44, C1.4 @ 14:16, C1.7 @ 18:36, C1.4 @ 22:47 UT
Region 13341 [S15E08] produced a few low level C flares. C1 flares: C1.5 @ 03:12, C1.5 @ 05:22 UT
Region 13345 [N09E04] decayed slowly and quietly.
Region 13346 [N09W20] was mostly quiet and stable. C1 flares: C1.4 @ 02:47 UT
Region 13347 [S18W37] decayed slowly and quietly.
Region 13348 [S31E31] decayed slowly and quietly.
Region 13349 [N09E26] decayed slowly and quietly.
Region 13350 [S12E29] was quiet and stable.
Region 13351 [N22E47] was quiet and stable.
New region 13352 [N09W58] emerged on June 23 with SWPC numbering the region the next day. C1 flares: C1.3 @ 23:38 UT

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S8676 [S12W12] reemerged with a tiny spot.
S8682 [N17W21] was quiet and stable.
S8699 [N17E49] was quiet and stable.
New region S8704 [N08E32] emerged with tiny spots.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.7 00:24 N19W40 13337 GOES16  
C2.4 07:21 S15E21 13341 GOES16  
C2.4 07:28   13337 GOES16  
C4.1 09:19 N21W40 13337 GOES16  
C2.0 10:13   13337 GOES16 simultaneous flare in AR 13340
M1.1 12:17 N21W42 13337 GOES16  
C2.7 16:10 S19W65 13335 GOES16  
C3.0 17:51 S12W11 13341 GOES16  
C2.1 18:21   13340 GOES16 simultaneous flare in AR 13335
C2.1 18:51   13340 GOES16 simultaneous flare in AR 13335
C2.2 19:34   13335 GOES16  
C4.9 21:17 S16W71 13335 GOES16  

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 either late on June 25 or on June 26.
June 23-24
: 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 minor storm conditions are expected for June 25-26 due to CME effects. Effects from CH1155 could reach Earth on June 27 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
      N17W68        

location: N18W63

SWPC added a duplicate region on June 19, AR 13343

13336 2023.06.13
2023.06.14
      S19W72          

location: S21W68

northern part merged with AR 13335 on June 21

13335 2023.06.13
2023.06.14
4 6 3 S14W73 0220 CSO DKO

area: 0280

location: S14W74

13337 2023.06.14
2023.06.15
6 17 7 N21W51 0060 CAO DRI

location: N21W48

13338 2023.06.14
2023.06.15
4 17 7 N11W51 0020 HRX CRO

area: 0035

S8670 2023.06.16       N07W39            
13339 2023.06.16
2023.06.17
7 28 14 S20W23 0110 CSO CSI beta-gamma

location: S19W23

13340 2023.06.17 18 37 24 N22W19 0200 EAI DAI beta-gamma-delta

area: 0330

location: N23W18

S8676 2023.06.18       S13W09            
13341 2023.06.18
2023.06.19
4 35 13 S16E09 0140 CAO CSO

area: 0220

13343 2023.06.19       N16W70           this is a duplicate of AR 13334
S8680 2023.06.19       S16W26            
S8682 2023.06.19   9 6 N17W21 0020   DRO  
13345 2023.06.19
2023.06.20
1 7 4 N09E07 0010 HRX CRO location: N09E04

area: 0030

13346 2023.06.20
2023.06.21
2 7 2 N10W20 0020 BXO CRO location: N09W20
13350 2023.06.20
2023.06.23
  4 1 S11E25 0008   BXO  
S8687 2023.06.20       N31W02          
S8688 2023.06.21       S28W37          
S8689 2023.06.21       N15E25            
13347 2023.06.21
2023.06.23
3 8 3 S18W38 0010 BXO CRO location: S18W37
S8691 2023.06.21       S07W59            
13348 2023.06.21
2023.06.23
2 4 1 S31E34 0020 BXO BXO location: S31E31

area: 0005

13349 2023.06.22
2023.06.23
2 5 2 N09E24 0020 BXO DRO location: N09E26
13351 2023.06.22
2023.06.23
1 1 1 N22E46 0030 HSX HAX area: 0040

location: N22E47

S8695 2023.06.22       N16E06            
S8697 2023.06.22       S14W26            
S8698 2023.06.22       N37E01            
S8699 2023.06.22   7 2 N17E49 0010   AXX  
13352 2023.06.23
2023.06.24
3 8 6 N08W59 0020 CRO DRI area: 0050
S8701 2023.06.23       S11W19          
S8702 2023.06.23       N38W25          
S8703 2023.06.23       N19W57          
13353 2023.06.24 3     S18W12 0010 BXO       location is inside the trailing spot section of AR 13339
S8704 2023.06.24   2 1 N08E32 0005   BXO    
Total spot count: 60 202 97  
Sunspot number: 200 382 277  (total spot count + 10 * number of spotted regions)
Weighted SN: 99 256 151  (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): 220 210 222  

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
2023.06 163.0 (1)   113.3 (2A) / 141.6 (2B) / 179.9 (2C) (134.3 projected, +3.1) (8.2)
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.