Solar Terrestrial Activity Report

Activity chart

Last major update issued on November 25, 2023 at 12:35 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 to unsettled on November 24. Solar wind speed at SOHO ranged between 364 and 471 km/sec. A transient disturbance was observed arriving at DSCOVR after 18h UT. A solar wind shock was observed at 07:54 UT on November 25, probably the arrival of the first of the Nov.22 CMEs. The high latitude magnetometer at Andenes recorded quiet to active levels.

Solar flux density measured at 20h UT on 2.8 GHz was 178.0 - increasing 50.0 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 157.14. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 7 (STAR Ap - based on the mean of three hour interval ap indices: 7.3). Three hour interval K indices: 21112233 (planetary), 12012212 (Boulder), 43211343 (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 13 active regions using 2K resolution (SN: 300) and in 13 active regions using 1K resolution (SN: 221) SDO/HMI images.

Region 13489 [S13W22] decayed slowly and quietly.
Region 13491 [N10E05] decayed slowly and quietly.
Region 13492 [N19E09] decayed further and produced low level C flares. C1 flares: C1.5 @ 00:11 UT
Region 13493 [S12E18] was mostly quiet and stable.
Region 13494 [S17E24] was mostly quiet and stable.
Region 13498 [S11W72] decayed slowly and quietly.
Region 13499 [S17W09] produced the only M flare of the day and was otherwise mostly quiet. C1 flares: C1.6 @ 11:23 UT
Region 13500 [S18E51] was mostly quiet despite its magnetic complexity. A major flare is still possible. C1 flares: C1.3 @ 19:25 UT
Region 13501 [S09E59] was mostly quiet and stable.
New region 13502 [N15E16] emerged on November 21/22 and was numbered by SWPC on Nov.24 as they split the region off AR 13492.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9156 [N22W01] decayed slowly and was mostly quiet.
S9173 [N12E32] reemerged with a tiny spot.
S9174 [N21E73] was quiet and stable.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.0 01:16   13492 GOES18  
C2.0 02:21   13492 GOES18  
C2.2 03:03   13492 GOES18  
C2.0 03:48   13502 GOES18  
C3.3 05:41   13502 GOES18  
C2.3 06:06   13502 GOES18  
C2.0 06:20   13501 GOES18  
C2.6 06:42   S9156 GOES18  
C3.3 07:03   13492 GOES18  
C2.2 07:40   13501 GOES18  
C2.6 08:47   13502 GOES18  
M1.1/1F 09:33 S16W02 13499 GOES18  
C2.5 10:19   13493 GOES18  
C7.5/1F 10:42 S15E34 13493 GOES18  
C2.2 13:38   13492 GOES18  
C5.5 22:19   S9156 GOES18  

Coronal mass ejections (CMEs)

November 23-24: No obviously Earth directed CMEs were observed.
November 22: A filament eruption in the southeast quadrant early in the day was associated with a partial halo CME. This CME may have an Earth directed component, in which case we could see geomagnetic effects on November 25. Another filament eruption in the southwest quadrant late in the day may have been associated with another partial halo CME, however, it is uncertain if this CME has any Earth directed component.

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 positive polarity northern hemisphere coronal hole (CH1189) was Earth facing on November 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

The geomagnetic field is expected to be quiet to minor storm on November 25-27, first due to CME effects, then due to effects from CH1189.

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
13488 2023.11.14
2023.11.14
      N31W60          

location: N29W55

13489 2023.11.16
2023.11.17
6 18 8 S15W23 0060 CAI CRO

location: S13W22

S9151 2023.11.16       S24W45            
13497 2023.11.18
2023.11.20
      N17W06         location: N18W02
S9156 2023.11.18   13 7 N22W01 0200   DAO beta-delta

SWPC apparently considers this region as two groups (13490 and 13495)

13490 2023.11.18 6     N20W03 0180 DAI        
S9157 2023.11.18       N13W44            
13492 2023.11.18
2023.11.20
21 38 16 N19E11 0380 EHI CSO

area: 0410

13491 2023.11.18
2023.11.19
2 7 3 N10E04 0060 HAX CAO location: N10E05
13496 2023.11.19
2023.11.20
      N09W20         location: N07W18
13493 2023.11.20
2023.11.20
2 17 8 S13E17 0080 CSO CSO

area: 0150

S9162 2023.11.20       S17E11            
13494 2023.11.20
2023.11.20
1 5 2 S18E23 0060 HSX CSO

area: 0160

13495 2023.11.20 2     N25E05           apparently the spots in  the northeastern part of AR S9156
S9166 2023.11.20       S33E09            
13498 2023.11.21
2023.11.21
1 2 1 S12W67 0020 HSX CAO

location: S11W72

13500 2023.11.22
2023.11.23
6 25 15 S19E50 0530 DKC DKC beta-delta

area: 0600

location: S18E51

13499 2023.11.22
2023.11.23
9 22 17 S17W09 0060 DAO DAI area: 0100
13501 2023.11.22
2023.11.23
1 1 1 S09E58 0060 HSX HSX area: 0140

location: S09E59

S9171 2023.11.22       N08W16          
13502 2023.11.22
2023.11.23
7 19 11 N14E13 0090 DAI DKO area: 0310

location: N15E16

S9173 2023.11.22   1 1 N12E32 0004   AXX    
S9174 2023.11.23   2 1 N21E73 0030   HRX  
Total spot count: 64 170 91  
Sunspot number: 184 300 221  (total spot count + 10 * number of spotted regions)
Weighted SN: 131 236 157  (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): 202 165 177  

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
2023.11 148.0 (1)   74.2 (2A) / 92.7 (2B) / 110.4 (2C) (137.8 projected max SC25, +2.6) (12.5)
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.