Solar Terrestrial Activity Report

Activity chart

Last major update issued on November 18, 2023 at 10:40 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 very quiet on November 17. Solar wind speed at SOHO ranged between 309 and 401 km/sec. The high latitude magnetometer at Andenes recorded quiet to unsettled levels.

Solar flux density measured at 20h UT on 2.8 GHz was 119.6 - decreasing 3.0 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 156.20. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 2.3). Three hour interval K indices: 00010110 (planetary), 10012221 (Boulder), 00000330 (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 5 active regions using 2K resolution (SN: 72 - lowest value since June 2022) and in 3 active regions using 1K resolution (SN: 39) SDO/HMI images.

Region 13486 [S09W75] decayed slowly and was mostly quiet. C1 flares: C1.2 @ 16:40, C1.5 @ 21:16 UT
New region 13489 [S15E72] rotated partly into view on November 16 and was numbered the next day by SWPC. C1 flares: C1.5 @ 10:10, C1.1 @ 11:05, C1.2 @ 13:58, C1.7 @ 15:02 UT

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9147 [N16W18] was quiet and stable.
New region S9153 [N22E15] emerged with tiny spots.
New region S9154 [S19E12] was observed with tiny spots in an old plage area.

An impulsive M1.2 flare was recorded at 05:42 UT on November 18 from an active region at the northeast limb. The same region produced a C1.4 flare at 17:53 UT on Nov.17. Two active region are rotating into view near the northeast limb at N17 and N22.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment

Coronal mass ejections (CMEs)

November 15, 17: No obviously Earth directed CMEs were observed.
November 16: A filament eruption began near 01:30 UT, peaked near 04:15 UT and covered parts of the northwestern quadrant from the central meridian. A slow moving partial halo CME was observed in LASCO imagery, the CME could reach Earth on November 19.

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 small negative polarity northern hemisphere hole (CH1186) rotated over the central meridian on November 14. A positive polarity northern hemisphere coronal hole (CH1187) is well defined and will be Earth facing on November 17-18. A positive polarity trans equatorial coronal hole (CH1188) formed just west of the central meridian on November 16. It is uncertain if CH1188 will cause any disturbance.

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

Forecast

The geomagnetic field is expected to be quiet November 18. November 19-20 could see quiet to minor storm conditions due to the November 16 CME. Quiet to active is likely on November 20-21 due to effects from CH1187.

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
S9133 2023.11.08       N08W53            
13486 2023.11.11
2023.11.12
4 4 3 S08W74 0120 DSO CSO area: 0150

location: S09W75

S9137 2023.11.12       N14W56            
S9139 2023.11.13       N07W47            
S9140 2023.11.13       N14W48            
S9141 2023.11.13       N25E28            
S9142 2023.11.13       N09W04            
13488 2023.11.14
2023.11.14
      N31E38        

location: N28E29

S9145 2023.11.14       S11W33            
S9146 2023.11.15       N16W48            
S9147 2023.11.15   5   N16W18 0010   BXO  
S9148 2023.11.15       S15W33            
S9149 2023.11.16       S08E29          
13489 2023.11.16
2023.11.17
2 8 5 S15E71 0060 CAO ESO location: S15E72

area: 0200

S9151 2023.11.16       S24E46          
S9152 2023.11.16       S14E12          
S9153 2023.11.17   2 1 N22E15 0006   AXX    
S9154 2023.11.17   3   S19E12 0006   BXO    
Total spot count: 6 22 9  
Sunspot number: 26 72 39  (total spot count + 10 * number of spotted regions)
Weighted SN: 16 32 19  (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): 29 39 31  

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
2023.11 140.8 (1)   44.5 (2A) / 78.6 (2B) / 94.2 (2C) (137.8 projected max SC25, +2.6) (13.7)
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.