Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 13, 2023 at 11:25 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 (July 6, 2023)
Solar cycle Solar cycles 23-25 (July 1, 2023) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (July 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 (July 1, 2023) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (July 1, 2023) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (July 10, 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 July 12. Solar wind speed at SOHO ranged between 280 and 371 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 193.3 - increasing 40.2 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 147.18. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.0). Three hour interval K indices: 21101221 (planetary), 22222321 (Boulder), 54122232 (Andenes).

The background x-ray flux is at the class C2 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 16 active regions using 2K resolution (SN: 322) and in 11 active regions using 1K resolution (SN: 187) SDO/HMI images.

Region 13361 [N24W63] decayed and lost mature penumbra on the trailing spots.
Region 13362 [S08W31] was quiet and stable.
Region 13363 [S21W07] was mostly quiet despite becoming more complex magnetically. The magnetic delta within the large spot strengthened. A major flare is possible.
Region 13364 [N23W24] was mostly quiet and stable.
Region 13366 [S10W84] lost all trailing spots and rotated quietly to the southwest limb.
Region 13367 [N10W41] decayed slowly and produced a few flares.
Region 13368 [S18W74] decayed slowly and quietly.
Region 13370 [S16E34] was quiet and stable.
Region 13371 [S15E47] decayed slowly and quietly.
Region 13372 [N23E66] became less active after a major M6 flare at 08:55 UT. There seems to be a magnetic delta in the trailing spot section and further major flares are possible.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S8752 [N15E20] decayed slowly and quietly.
S8753 [S29E40] decayed slowly and quietly.
S8756 [S13E21] was quiet and stable.
New region S8758 [N26E29] emerged with tiny spots.
New region S8759 [S01E05] emerged with a tiny spot.
New region S8760 [S08W58] emerged with tiny spots.

What looks like a very weak solar wind shock was observed at DSCOVR at 11:10 UT on July 13, probably the arrival of the July 10 CME.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
M1.4 00:31   13366 GOES16 simultaneous flares in AR 13368 and 13372
C7.5 00:57   13366 GOES16  
C6.1 01:28   13372 GOES16  
C8.7 02:19 N24E77 13372 GOES16  
C7.6 02:42   13372 GOES16  
C7.2 03:15   13372 GOES16  
C7.6 03:33   13367 GOES16 simultaneous flare in AR 13364
M1.34 04:44   13361 GOES16  
M1.36 04:49   13372 GOES16  
M1.3 05:14   13361 GOES16 simultaneous flare in AR 13372
C5.6 06:17   13372 GOES16  
C3.3 07:20   13372 GOES16  
C3.2 07:49   13372 GOES16  
C4.1 08:32   13361 GOES16 simultaneous flare in AR 13368
C5.9 08:43   13361 GOES16  
M6.9/1N 08:55 N24E77 13372 GOES16  
C6.7 09:32   13361 GOES16  
C5.0 10:20   13372 GOES16  
C9.1 10:29   13361 GOES16  
C4.0 10:50   13368 GOES16  
C3.3 11:39   13360 GOES16  
C3.2 13:37   13368 GOES16 simultaneous flare in AR 13363
C4.7/1N 15:05 N23W58 13361 GOES16  
C3.2 16:01   13372 GOES16  
C3.6 16:16   13372 GOES16  
C3.0 17:03   13372 GOES16  
C3.6 17:32   13361 GOES16  
C3.9 18:40   13372 GOES16  
C4.9 19:38   13372 GOES16  
C3.2 20:24   13372 GOES16  
C3.1 20:48   13372 GOES16  
C3.3 21:33   13372 GOES16  
C3.6 22:30   13372 GOES16  
C5.5 22:50 S25W08 13363 GOES16  
C6.4 22:57   13372 GOES16  
C7.0 23:06   13372 GOES16  
C4.1 23:42   13372 GOES16  

Coronal mass ejections (CMEs)

July 10: An asymmetrical full halo CME was observed after the M2 flare in AR 13366 at 03:55 UT. The main part of the ejecta is not headed towards Earth, however, components of the CME will likely reach us either late on July 12 or on July 13 and cause unsettled to minor storm conditions.
July 11: An asymmetrical full halo CME was observed after 19:36 UT following a large filament eruption near and to the southwest of AR 13363. The CME could reach Earth on July 14 and cause unsettled to major storm conditions.
July 12: 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 northern hemisphere coronal hole (CH1159) rotated across the central meridian on July 10. CH1159 lost a large part of its area after July 7 due to the development of AR 13367. A large trans equatorial area of weak corona has become CH1160. CH1160 will be Earth facing July 11-13.

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

The geomagnetic field is expected to be quiet to active on July 13-16 due to CME and coronal hole effects, minor storm intervals are possible on July 14 if the July 11 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
13366 2023.06.30
2023.07.07
1 1 1 S11W83 0090 CSO CKO

area: 0280

location: S10W84

13360 2023.06.30
2023.07.01
1     N23W89 0000 AXX     rotated out of view
13368 2023.07.02
2023.07.09
11 13 7 S17W78 0080 DAI DRI  
13361 2023.07.02
2023.07.04
13 16 7 N25W65 0220 DSI DSI

location: N24W63

13362 2023.07.04
2023.07.05
1 3 2 S08W34 0020 HRX HAX location: S08W31

area: 0030

13363 2023.07.05
2023.07.06
24 40 14 S21W09 0850 DKO DKC beta-delta

location: S22W07

area: 1080

13364 2023.07.05
2023.07.06
5 11 7 N25W26 0010 BXO CRO location: N24W25

area: 0020

13367 2023.07.07
2023.07.08
18 26 14 N10W41 0160 DAI EAI beta-gamma
S8743 2023.07.07       N24W47            
13369 2023.07.08
2023.07.09
2     S18W65 0000 AXX     spotless

location: S19W62

S8746 2023.07.08       S29W29            
13370 2023.07.09
2023.07.10
8 15 9 S15E33 0030 DRO DRI area: 0040

location: S16E34

S8748 2023.07.09       N31W20            
S8749 2023.07.09       S02W56            
13371 2023.07.10
2023.07.11
2 4 2 S15E48 0030 HAX HAX area: 0110

location: S15E47

S8752 2023.07.10   1 1 N15E20 0003   AXX  
S8753 2023.07.10   2   S29E40 0002   BXO  
13372 2023.07.11
2023.07.11
13 23 13 N24E65 0650 EKI FHC

location: N23E66

area: 1300

S8755 2023.07.11       N51W05          
S8756 2023.07.11   1   S13E21 0003   AXX  
S8757 2023.07.11       N21E02          
S8758 2023.07.12   3   N26E29 0004   BXO    
S8759 2023.07.12   1   S01E05 0001   AXX    
S8760 2023.07.12   2   S08W58 0002   BXO    
Total spot count: 99 162 77  
Sunspot number: 219 322 187  (total spot count + 10 * number of spotted regions)
Weighted SN: 150 221 136  (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): 241 177 150  

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
2021.12 103.0 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
2022.12 147.9 143.4 112.8 106.6 (+5.6) 10.99
2023.01 182.4 176.6 143.6 (113.7 projected, +6.1) 8.73
2023.02 167.2 163.2 110.9 (118.5 projected, +4.8) 14.48
(current
SC25 peak)
2023.03 157.2 155.6 122.6 (121.6 projected, +3.1) 14.42
2023.04 145.4 146.4 96.4 (127.0 projected, +5.4) 13.40
2023.05 155.6 159.2 137.9 (132.7 projected, +5.7) 10.67
2023.06 161.7 166.8 163.4 (135.9 projected, +3.2) 8.9
2023.07  173.9 (1)   59.9 (2A) / 154.8 (2B) / 172.1 (2C) (135.4 projected, -0.5) (6.2)
2023.08       (136.4 projected, +1.0)  
2023.09       (139.8 projected, +3.4)  
2023.10       (141.6 projected, +1.8)  
2023.11       (144.2 projected max SC25, +2.6)  
2023.12       (143.4 projected, -0.1)  
2024.01       (140.1 projected, -3.3)  

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.