Solar Terrestrial Activity Report

Activity chart

Last major update issued on December 2, 2023 at 06:45 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 (December 1, 2023) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (December 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 (December 1, 2023) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (December 1, 2023) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (November 26, 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 active to severe storm on December 1 due to CME effects. Solar wind speed at SOHO ranged between 435 and 586 km/sec. The high latitude magnetometer at Andenes recorded active to major storm levels. A solar wind shock was recorded at SOHO at 08:50 UT as the November 28 CME arrived.

Solar flux density measured at 20h UT on 2.8 GHz was 162.0 - increasing 6.7 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 158.34. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 49 (STAR Ap - based on the mean of three hour interval ap indices: 49.3). Three hour interval K indices: 44476555 (planetary), 43366444 (Boulder), 65465565 (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 14 active regions using 2K resolution (SN: 226) and in 11 active regions using 1K resolution (SN: 160) SDO/HMI images.

Region 13492 [N18W80] decayed slowly and was mostly quiet.
Region 13493 [S12W76] decayed slowly and was mostly quiet. C1 flares: C1.4 @ 08:14, C1.6 @ 15:01, C1.7 @ 17:35 UT
Region 13494 [S17W68] was quiet and stable.
Region 13500 [S18W42] decayed slightly and produced several flares. C1 flares: C1.5 @ 06:08, C1.6 @ 06:43, C1.7 @ 09:42, C1.4 @ 10:58, C1.6 @ 13:16, C1.8 @ 18:07, C1.6 @ 18:48 UT
Region 13501 [S08W34] was quiet and stable.
Region 13502 [N14W80] decayed slowly and was mostly quiet. C1 flares: C1.8 @ 10:11, C1.5 @ 16:14 UT
Region 13503 [N20W20] was quiet and stable.
Region 13505 [S17E29] was quiet and stable.
Region 13507 [N08E41] was quiet and stable.
Region 13508 [S14E39] was quiet and stable.
New region 13509 [N12W51] emerged quickly with several spots. C flares are possible.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9188 [N09W46] decayed slowly and quietly.
New region S9193 [S22W24] was observed with tiny spots in an old plage area.
New region S9194 [S10E52] was observed with tiny spots in an old plage area.

AR 13499 produced a C1.9 flare at 13:28 UT.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C4.8 03:11   13492 GOES18  
M1.1 04:39   13502 GOES18  
C5.2 11:59   13500 GOES18  
C2.3 19:11   13493 GOES18  
C3.3 19:27   13500 GOES18  
M1.0 21:20   13500 GOES18 LDE, partial halo CME
simultaneous flare in AR 13493
C5.6 22:45   13500 GOES18  
C4.8 23:07   13500 GOES18  
C4.4 23:58   13492 GOES18  

Coronal mass ejections (CMEs)

November 29-30: No obviously Earth directed CMEs were observed.
December 1: A partial halo CME was observed after an M1.0 flare in AR 13500 late in the day. This CME could reach Earth on December 4 and contribute to the expected CH1190 disturbance.

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 large recurrent negative polarity trans equatorial coronal hole (CH1190) will rotate across the central meridian on December 1-3.

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 December 2 due to CME effects. Effects from CH1190 could cause unsettled to major storm conditions on December 3-5 and quiet to active on December 6. Effects from the December 1 CME could contribute to the ongoing distrubance on December 4-5.

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
13492 2023.11.18
2023.11.20
2 1 1 N19W87 0050 CSO HSX

area: 0080

location: N18W80

13493 2023.11.20
2023.11.20
  1 1 S13W75 0004   AXX

location: S12W76

13494 2023.11.20
2023.11.20
1 1 1 S17W68 0030 HSX HSX

area: 0090

13500 2023.11.22
2023.11.23
15 36 24 S18W44 0280 EKC EAC beta-gamma-delta

location: S18W42

area: 0440

13501 2023.11.22
2023.11.23
1 7 5 S09W35 0040 HSX CSO area: 0090

location: S08W34

13502 2023.11.22
2023.11.23
5 5 2 N14W81 0030 CSO DAO area: 0090

location: N14W80

S9173 2023.11.22       N13W59            
13503 2023.11.23
2023.11.25
2 5 2 N19W20 0010 AXX BXO

locaton: N20W20

13506 2023.11.26
2023.11.29
      N15W57        

location: N15W47

13505 2023.11.27
2023.11.28
1 2 2 S17E29 0030 HSX HSX area: 0090
13508 2023.11.28
2023.11.29
1 2 1 S15E38 0060 HSX HSX area: 0200

location: S14E39

13507 2023.11.28
2023.11.29
1 2 2 N08E40 0080 HSX HKX area: 0330

location: N08E41

S9186 2023.11.28       S09W12            
S9188 2023.11.30   3   N09W46 0005   BXO  
S9189 2023.11.30       N28W13          
S9190 2023.11.30       S10W37          
S9191 2023.11.30       S13W46          
13509 2023.12.01
2023.12.01
11 17 9 N10W50 0030 CRI DAO   was AR S9192

location: N12W51

area: 0130

S9193 2023.12.01   2   S22W24 0004   AXX    
S9194 2023.12.01   2   S10E52 0003   BXO  

 

Total spot count: 40 86 50  
Sunspot number: 140 226 160  (total spot count + 10 * number of spotted regions)
Weighted SN: 88 136 100  (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): 154 124 128  

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
2023.05 155.6 159.2 137.4 123.9 (+1.2) 10.67
2023.06 161.7 166.8 160.5 (126.3 projected, +2.4) 8.95
2023.07  176.4 182.2 159.1 (127.1 projected, +0.8) 8.15
2023.08  153.7 157.6 114.8 (128.2 projected, +1.1) 7.19
2023.09  154.4 156.0 133.6 (130.4 projected, +2.2) 14.26
2023.10  142.8 141.9 99.4 (132.2 projected, +1.8) 8.16
2023.11 153.5 150.2 105.4 (134.1 projected max SC25, +1.9) 12.3
2023.12 162.0 (1)   4.5 (2A) / 140 (2B) / 124.9 (2C) (132.7 projected, -1.4) (49.3)
2024.01       (130.0 projected, -2.7)  
2024.02       (129.9 projected, -0.1)  
2024.03       (129.3 projected, -0.6)  
2024.04       (130.1 projected, +0.8)  
2024.05       (132.2 projected, +2.1)  
2024.06       (131.5 projected, -0.7)  

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.