Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 24, 2023 at 10:30 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 23. Solar wind speed at SOHO ranged between 376 and 491 km/sec. The high latitude magnetometer at Andenes recorded quiet to minor storm levels. A sudden minor increase in solar wind speed, density and temperature was recorded at 18:03 UT at DSCOVR. This may have been the arrival of the June 20 CME.

Solar flux density measured at 20h UT on 2.8 GHz was 169.7 - increasing 12.8 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 144.41. 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: 8.6). Three hour interval K indices: 22122232 (planetary), 22232322 (Boulder), 42134455 (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 22 active regions using 2K resolution (SN: 469) and in 20 active regions using 1K resolution (SN: 312) SDO/HMI images.

Region 13334 [N18W50] decayed slowly and was mostly quiet. C1 flares: C1.9 @ 18:44 UT
Region 13335 [S14W61] was mostly quiet and stable. C1 flares: C1.9 @ 11:31, C1.6 @ 12:35 UT
Region 13337 [N19W35] lost mature penumbra and produced low level C flares. C1 flares: C1.5 @ 10:33, C1.5 @ 23:27 UT
Region 13338 [N10W37] decayed slowly and was mostly quiet. C1 flares: C1.7 @ 08:35, C1.8 @ 14:13 UT
Region 13339 [S20W10] was mostly quiet and stable.
Region 13340 [N22W07] decayed slightly but could still produce a minor M class flare. C1 flares: C1.9 @ 05:06, C1.6 @ 06:22, C1.8 @ 07:00, C1.5 @ 11:11, C1.6 @ 23:18 UT
Region 13341 [S16E22] was mostly quiet and stable. C1 flares: C1.9 @ 08:04, C1.5 @ 09:23, C1.9 @ 17:00 UT
Region 13345 [N08E18] decayed slowly and quietly.
Region 13346 [N08W05] was quiet and stable.
New region 13347 [S19W24] emerged on June 21 and was numbered by SWPC 2 days later as the region began to decay.
New region 13348 [S31E48] emerged on June 21 with SWPC discovering the region 2 days later.
New region 13349 [N08E38] emerged on June 22 and received its NOAA number the following day.
New region 13350 [S12E39] emerged on June 20 and was numbered by SWPC 3 days later as the region decayed. C1 flares: C1.6 @ 21:45 UT
New region 13351 [N22E59] rotated into view on June 22 with a small, mature spot.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S8682 [N17W06] was quiet and stable.
S8687 [N31E11] decayed slowly and quietly.
S8688 [S28W24] decayed slowly and quietly.
S8699 [N16E62] was quiet and stable.
New region S8700 [N08W43] emerged before noon with several spots.
New region S8701 [S11W06] emerged with a tiny spot.
New region S8702 [N38W12] emerged with a tiny spot.
New region S8703 [N19W44] emerged with tiny spots.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.0 02:46   13340 GOES16  
C2.1 02:55   13350 GOES16  
C2.1 03:06   13335 GOES16  
C4.6 03:32 N20W26 13337 GOES16  
C2.9 10:04 S15W50 13335 GOES16  
C2.0 16:46   13337 GOES16 simultaneous flare in AR 13335
C2.7 21:02 N22W32 13337 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 on June 26.
June 21, 23
: 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 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 geomagnetic conditions are expected for June 24-26. Effects from CH1155 could reach Earth on June 27 and cause a few unsettled and active intervals. Components from the June 22-23 CME could reach Earth on June 26 and cause some active and minor storm 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
13333 2023.06.12
2023.06.13
      S11W85         location: S09W89
13334 2023.06.13
2023.06.13
  2 1 N17W54 0005   BXO

location: N18W50

SWPC added a duplicate region on June 19, AR 13343

13336 2023.06.13
2023.06.14
      S19W58          

location: S21W55

northern part merged with AR 13335 on June 21

13335 2023.06.13
2023.06.14
9 16 7 S15W58 0230 DSO DKO

area: 0300

location: S14W61

S8661 2023.06.14       N22W49            
13337 2023.06.14
2023.06.15
6 21 12 N20W38 0080 DAO DRI beta-gamma

location: N19W35

area: 0120

13338 2023.06.14
2023.06.15
5 16 8 N11W37 0020 CRO DRI

area: 0040

location: N10W37

S8670 2023.06.16       N07W26            
13339 2023.06.16
2023.06.17
9 34 14 S20W11 0110 CAO ESI beta-gamma

area: 0130

location: S20W10

13340 2023.06.17 13 41 19 N22W07 0160 ESI DAI beta-gamma

area: 0230

S8676 2023.06.18       S13E04            
13341 2023.06.18
2023.06.19
5 27 10 S16E22 0200 CSO CAO

area: 0240

S8678 2023.06.18       S01W53            
13343 2023.06.19       N16W56           this is a duplicate of AR 13334
13344 2023.06.19
2023.06.20
1     N24W85 0010 AXX     rotated out of view
S8680 2023.06.19       S16W13            
S8682 2023.06.19   12 4 N17W06 0020   CRO  
13345 2023.06.19
2023.06.20
3 13 5 N08E19 0020 CRO CRO location: N08E18

area: 0030

13346 2023.06.20
2023.06.21
  10 5 N08W06 0020   CRO location: N08W05
13350 2023.06.20
2023.06.23
1 4 2 S11E39 0010 AXX AXX  
S8687 2023.06.20   3   N31E11 0005   AXX  
S8688 2023.06.21   8 2 S28W24 0010   AXX  
S8689 2023.06.21       N15E38            
13347 2023.06.21
2023.06.23
5 14 6 S17W26 0030 CRO CRO location: S19W24
S8691 2023.06.21       S07W46            
13348 2023.06.21
2023.06.23
3 5 3 S31E46 0020 BXO CRO location: S31E48
13349 2023.06.22
2023.06.23
3 8 5 N09E38 0020 BXO DRO location: N08E38

area: 0040

13351 2023.06.22
2023.06.23
1 1 1 N22E59 0020 HSX HAX area: 0040
S8695 2023.06.22       N16E19          
S8697 2023.06.22       S14W13          
S8698 2023.06.22       N37E14          
S8699 2023.06.22   2 1 N16E62 0004   AXX  
S8700 2023.06.23   8 5 N08W43 0035   DRO    
S8701 2023.06.23   1 1 S11W06 0004   AXX    
S8702 2023.06.23   1   N38W12 0002   AXX    
S8703 2023.06.23   2 1 N19W44 0004   BXO    
Total spot count: 64 249 112  
Sunspot number: 194 469 312  (total spot count + 10 * number of spotted regions)
Weighted SN: 103 306 169  (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): 213 258 250  

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
2023.06 163.1 (1)   106.6 (2A) / 139.0 (2B) / 177.9 (2C) (134.3 projected, +3.1) (8.0)
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.