Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 15, 2023 at 15:50 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 unsettled on June 14. Solar wind speed at SOHO ranged between 335 and 422 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 143.5 - decreasing 7.1 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 143.69. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.5). Three hour interval K indices: 31100101 (planetary), 31011312 (Boulder), 52110101 (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: 264) and in 12 active regions using 1K resolution (SN: 170) SDO/HMI images.

Region 13326 [N25W80] was mostly quiet and stable.
Region 13327 [S17W63] decayed slowly and was mostly quiet. C1 flares: C1.6 @ 03:36, C1.4 @ 12:08 UT
Region 13329 [N23W63] decayed slowly and was mostly quiet. C1 flares: C1.7 @ 08:04 UT
Region 13331 [S23W26] decayed and lost the magnetic delta.
Region 13333 [S11E36] extended but didn't gain spots. C flares are possible. C1 flares: C1.8 @ 03:58, C1.7 @ 04:47, C1.6 @ 10:09, C1.2 @ 19:57 UT
Region 13334 [N17E61] decayed slowly and quietly.
New region 13335 [S14E65] rotated into view on June 13 and was numbered the next day by SWPC. The region produced a number of C flares and has minor M class flare potential. C1 flares: C1.9 @ 09:05, C1.5 @ 13:34, C1.3 @ 16:53, C1.4 @ 18:16, C1.8 @ 19:21, C1.9 22:11 UT
New region 13336 [S21E69] rotated into view on June 13 with SWPC numbering the region the following day. The region has M class flare potential. C1 flares: C1.7 @ 05:21 UT

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S8629 [N08W46] decayed slowly and quietly.
S8636 [N27W37] reemerged with tiny spots.
S8639 [S12E11] decayed slowly and quietly.
New region S8660 [S20W09] emerged with tiny spots
New region S8661 [N22E68] rotated into view with a tiny spot.
New region S8662 [N16E82] rotated into view with tiny spots.
New region S8663 [N11E83] rotated into view with a tiny spot.
New region S8664 [S10W12] emerged with a tiny spot.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.0 00:19   13335 GOES16  
C2.9 01:05   13335 GOES16  
C3.6 01:14   13333 GOES16  
C2.0 07:00   13333 GOES16  
C2.0 09:31   13329 GOES16 incorrectly attributed to AR 13335 by SWPC
C3.7 15:16 S15E67 13335 GOES16  
C3.6/1F 20:37 S14E65 13335 GOES16  
C6.6 22:59 S17W56 13327 GOES16  
C5.0 23:38 northeast limb S8662 GOES16  

Coronal mass ejections (CMEs)

June 12-14: 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 12-15. A southern hemisphere coronal hole (CH1154) will likely become Earth facing on June 16-17.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle and high latitudes is fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

Quiet to active conditions are expected for June 15-17 due to effects from CH1153, isolated minor storm intervals are possible.

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
13326 2023.06.02
2023.06.02
1 1 1 N25W80 0050 HSX HSX

area: 0100

13327 2023.06.03
2023.06.04
  6 1 S17W65 0010   BXO

location: S17W63

S8629 2023.06.04   1   N08W46 0002   AXX  
13330 2023.06.05
2023.06.06
      N18W87          

location: N17W84

13329 2023.06.05
2023.06.06
2 7 4 N23W66 0090 CAO CAO location: N23W63

area: 0060

13331 2023.06.06
2023.06.07
6 17 6 S23W28 0090 CAO CAO

area: 0130

13332 2023.06.07
2023.06.07
      S08W21          

 

S8636 2023.06.07   4 1 N27W37 0006   BXO    
S8639 2023.06.09   3   S12E11 0005   BXO  
S8640 2023.06.09       N12W28            
S8641 2023.06.09       S11W48            
S8642 2023.06.10       S16W29            
S8645 2023.06.10       S24W49            
S8646 2023.06.10       S29E28            
S8649 2023.06.10       S20E18            
S8651 2023.06.11       S12E01          
S8652 2023.06.11       N18E28            
13333 2023.06.12
2023.06.13
16 24 12 S11E36 0140 DAI DAI area: 0230
13334 2023.06.13
2023.06.13
2 5 4 N17E56 0060 HAX AXX

area: 0015

location: N17E61

13336 2023.06.13
2023.06.14
5 15 9 S20E66 0160 CSO DAI beta-gamma

location: S21E69

S8657 2023.06.13       N20W17          
13335 2023.06.13
2023.06.14
5 13 6 S15E63 0140 DAO EAO area: 0240
S8659 2023.06.13       S13W12          
S8660 2023.06.14   3 3 S20W09 0015   CRO    
S8661 2023.06.14   1   N22E68 0001   AXX    
S8662 2023.06.14   2 2 N16E82 0008   AXX   maybe BXO
S8663 2023.06.14   1   N11E83 0001   AXX    
S8664 2023.06.14   1 1 S10W12 0003   AXX    
Total spot count: 37 104 50  
Sunspot number: 107 264 170  (total spot count + 10 * number of spotted regions)
Weighted SN: 72 137 83  (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): 118 145 136  

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) 10.9
2023.06 160.8 (1)   60.9 (2A) / 130.5 (2B) / 160.3 (2C) (134.3 projected, +3.1) (5.1)
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.