Solar Terrestrial Activity Report

Activity chart

Last major update issued on November 21, 2023 at 06:55 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 (November 5, 2023)
Solar cycle Solar cycles 23-25 (November 1, 2023) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (November 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 (November 1, 2023) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (November 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 November 20. Solar wind speed at SOHO ranged between 311 and 370 km/sec. The high latitude magnetometer at Andenes recorded quiet to unsettled levels. Weak effects from CH1187 were noticed late in the day. Early on Nov.21 the disturbance is increasing.

Solar flux density measured at 20h UT on 2.8 GHz was 156.5 - increasing 35.4 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 156.40. 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: 4.1). Three hour interval K indices: 11121111 (planetary), 10212211 (Boulder), 20111123 (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 15 active regions using 2K resolution (SN: 275) and in 13 active regions using 1K resolution (SN: 201) SDO/HMI images.

Region 13488 [N29W02] was quiet and stable.
Region 13489 [S15E32] developed significantly. Magnetic delta structures formed in both the northern and southern spot sections. M class flaring is likely. C1 flares: C1.7 @ 00:36. C1.7 @ 02:29 UT
Region 13491 [N10E58] was mostly quiet and stable.
New region 13492 [N18E63] rotated into view on November 18-19 and was numbered by SWPC on Nov.20. The region is complex and has mixed polarities and a magnetic delta structure in a southern penumbra. A major flare is possible.
New region 13493 [S12E72] rotated into view early in the day with a mature spot. C1 flares: C1.9 @ 02:56, C1.8 @ 22:29 UT
New region 13494 [S17E77] rotated into view with a mature spot. C1 flares: C1.9 @ 17:18 UT
New region 13496 [N07E36] emerged on November 19 and was numbered by SWPC the following day.
New region 13497 [N18E49] rotated into view on November 18 and was numbered by SWPC two days later.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9154 [S18W25] was quiet and stable.
S9156 [N23E52] was mostly quiet and stable.
S9157 [N13E08] reemerged with a tiny spot.
New region S9162 [S17E61] emerged with a few spots.
New region S9164 [S09W13] emerged with several spots.
New region S9165 [N47W26] emerged with tiny spots at an unusually high latitude.
New region S9166 [S33E48] was observed with a tiny spot in an old plage area.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.9 03:11   13491 GOES18  
C2.0 04:34   13491 GOES18  
C2.2 05:31   13489 GOES18  
C2.1 06:11   13491 GOES18  
C3.8 07:06   13492 GOES18  
C3.8 07:33   13492 GOES18  
C3.3 07:42   13492 GOES18  
C2.3 08:06   13491 GOES18  
C2.1 08:36   13492 GOES18  
M1.2 09:03   13492 GOES18  
C4.8 09:25   13492 GOES18  
C2.0 09:52   13489 GOES18  
C5.0 10:14   13492 GOES18  
C8.0 12:31   13492 GOES18  
C2.7 13:12   13489 GOES18  
C2.0 13:37   13489 GOES18  
C3.5 14:07   13492 GOES18  
C2.4 15:04   13492 GOES18  
C2.1 16:23   13492 GOES18  
C2.0 17:03   13492 GOES18  
C2.8 20:57   13489 GOES18  
C2.7 21:10   13492 GOES18  
C2.0 23:05   13491 GOES18  
C3.1 23:42   13492 GOES18  

Coronal mass ejections (CMEs)

November 18-20: 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 well defined positive polarity northern hemisphere coronal hole (CH1187) was Earth facing on November 17-18. A positive polarity northern hemisphere coronal hole (CH1189) will likely become Earth facing on November 23.

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 to good. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet to active on November 21 and quiet to unsettled on November 22 due to effects from CH1187. Quiet conditions are likely on November 23-24.

Coronal holes (1) Coronal mass ejections (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
S9141 2023.11.13       N25W11            
S9142 2023.11.13       N09W43            
13488 2023.11.14
2023.11.14
  11 3 N31W04 0020   BXO

location: N29W02

S9147 2023.11.15       N19W41            
S9149 2023.11.16       S08W10            
13489 2023.11.16
2023.11.17
20 39 24 S16E32 0230 DAI DAC

beta-delta

area: 0310

location: N15E32

S9151 2023.11.16       S24E07            
S9152 2023.11.16       S14W27            
S9153 2023.11.17       N22W24            
S9154 2023.11.17   5 2 S18W25 0007   BXO  
13497 2023.11.18
2023.11.20
1 7 3 N16E50 0080 HSX CAO area: 0050
S9156 2023.11.18   11 6 N23E52 0190   DAO SWPC apparently considers this region as two groups (13490 and 13495)
13490 2023.11.18 1     N17E47 0040 HAX       duplicate of AR 13497, or incorrect location?
S9157 2023.11.18   1   N13E08 0002   AXX    
13492 2023.11.18
2023.11.20
7 28 20 N18E64 0280 DHI EKC beta-delta

area: 0620

13491 2023.11.18
2023.11.19
1 1 1 N13E55 0040 HSX HSX location: N10E58

area: 0090

13496 2023.11.19
2023.11.20
3 7 4 N09E36 0010 BXO DRO location: N07E36

area: 0040

13493 2023.11.20
2023.11.20
1 1 1 S12E69 0030 HAX HSX   was AR S9161

location: S12E72

area: 0140

S9162 2023.11.20   4 2 S17E62 0010   BXO    
13494 2023.11.20
2023.11.20
1 1 1 S15E78 0030 HAX HSX   was AR S9163

location: S17E77

area: 0170

13495 2023.11.20 2     N27E59 0030 HRX        
S9164 2023.11.20   6 3 S09W13 0020   DRO    
S9165 2023.11.20   2 1 N47W26 0005   AXX    
S9166 2023.11.20   1   S33E48 0001   AXX    
Total spot count: 37 125 71  
Sunspot number: 127 275 201  (total spot count + 10 * number of spotted regions)
Weighted SN: 80 171 117  (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): 140 151 161  

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
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 92.6 (+5.9) 10.92
2022.09 135.1 136.5 96.0 96.5 (+3.9) 12.18
2022.10 133.5 132.7 95.5 98.9 (+2.4) 11.16
2022.11 123.4 120.7 80.5 101.2 (+2.3) 9.33
2022.12 147.9 143.4 112.8 106.7 (+5.5) 10.99
2023.01 182.4 176.6 144.4 113.3 (+6.6) 8.73
2023.02 167.2 163.2 111.3 117.8 (+3.5) 14.48
(current
SC25 peak)
2023.03 157.2 155.6 123.3 121.0 (+3.2) 14.42
2023.04 145.4 146.4 97.6 122.7 (+1.7) 13.40
2023.05 155.6 159.2 137.4 (124.7 projected, +2.0) 10.67
2023.06 161.7 166.8 160.5 (127.9 projected, +3.2) 8.95
2023.07  176.4 182.2 159.1 (128.3 projected, +0.4) 8.15
2023.08  153.7 157.6 114.8 (130.1 projected, +1.8) 7.19
2023.09  154.4 156.0 133.6 (133.5 projected, +3.4) 14.26
2023.10  142.8 141.9 99.4 (135.2 projected, +1.7) 8.16
2023.11 140.9 (1)   51.8 (2A) / 77.7 (2B) / 95.1 (2C) (137.8 projected max SC25, +2.6) (12.4)
2023.12       (137.1 projected, -0.7)  
2024.01       (134.4 projected, -2.7)  
2024.02       (134.2 projected, -0.2)  
2024.03       (133.7 projected, -0.5)  
2024.04       (134.5 projected, +0.8)  
2024.05       (135.8 projected, +1.3)  

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

Update on the progress of solar cycle 25 as of August 20, 2023

Looking back 6 months, the 365d smoothed values for solar flux and all sunspot numbers with the exception of NOAA's, are all above their solar cycle 24 peak. The first peak of solar cycle 25 is forecast to be between July 7 and 10, 2023 (solar flux on July 7, ISN and STAR 1K and 2K all have that peak on July 9, while NOAA peaks on July 10). This is unlikely to be the final peak of SC25, however, there is a small probability that it is the actual sunspot and solar flux maximum.

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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.