Solar Terrestrial Activity Report

Activity chart

Last major update issued on November 27, 2023 at 06:15 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 (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 quiet to active on November 26 due to effects from CH1189. Solar wind speed at SOHO ranged between 481 and 630 km/sec. The high latitude magnetometer at Andenes recorded quiet to major storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 180.2 - increasing 40.5 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 157.52. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.1). Three hour interval K indices: 43322012 (planetary), 434322231 (Boulder), 65312124 (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 16 active regions using 2K resolution (SN: 331) and in 14 active regions using 1K resolution (SN: 232) SDO/HMI images.

Region 13489 [S14W48] decayed slowly and was mostly quiet.
Region 13492 [N18W17] decayed slowly and was mostly quiet. C1 flares: C1.9 @ 05:55 UT
Region 13493 [S12W07] was quiet and stable.
Region 13494 [S17W02] was quiet and stable.
Region 13499 [S17W36] was mostly quiet and stable. The region has weak polarity intermixing. C1 flares: C1.5 @ 15:04 UT
Region 13500 [S18E24] was mostly quiet and still has M class flare potential. C1 flares: C1.3 @ 11:23, C1.8 @ 16:07 UT
Region 13501 [S09E32] was quiet and stable.
Region 13502 [N14W11] decayed slowly and was mostly quiet. C1 flares: C1.3 @ 15:50 UT
Region 13503 [N21E48] developed slowly and quietly.
New region 13504 [N11W67] emerged on November 25 and developed further on Nov.26 when it was numbered by SWPC. C1 flares: C1.3 @ 14:49 UT

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9156 [N22W27] produced a C flares and decayed slowly. C1 flares: C1.2 @ 01:37, C1.4 @ 03:25, C1.7 @ 20:38 UT
S9173 [N11E04] was quiet and stable.
New region S9178 [N17E21] emerged with tiny spots.
New region S9179 [S22W47] emerged with a tiny spot before noon, then decayed slowly. C1 flares: C1.7 @ 05:46, C1.3 @ 13:20 UT
New region S9180 [N38W03] emerged with a tiny spot.
New region S9181 [S19W23] emerged with tiny spots.

An active region behind the southeast limb may be capable of M class flaring.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.6 07:43 N19W17 S9156 GOES18  
C2.7 12:57   13500 GOES18  

Coronal mass ejections (CMEs)

November 24-26: No obviously Earth directed CMEs were observed.
November 27: An interesting filament eruption was observed beginning just before 05h UT in SDO/AIA imagery. The eruption in the southwestern quadrant extended from close to the central meridian at its southernmost location to near the equator in the northwestern part of the eruption. Coronal dimming was observed. Any CME associated with this event would be likely to reach Earth on November 30.

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. A large recurrent negative polarity southern hemisphere coronal hole (CH1190) will likely rotate across the central meridian on December 1-2.

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 unsettled on November 27 due to effects from CH1189. Quiet conditions are likely on November 28-29.

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
      N31W88          

location: N29W81

13489 2023.11.16
2023.11.17
3 7 2 S14W50 0010 AXX CRO

location: S14W48

13497 2023.11.18
2023.11.20
      N17W34           location: N18W28
S9156 2023.11.18   11 8 N22W27 0090   CAO

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

13490 2023.11.18 6     N22W27 0090 CAI        
13492 2023.11.18
2023.11.20
9 24 13 N19W18 0210 HAX CSO

area: 0340

location: N18W17

13491 2023.11.18
2023.11.19
      N11W23         location: N10W21
13496 2023.11.19
2023.11.20
      N09W48           location: N07W44
13493 2023.11.20
2023.11.20
4 6 3 S13W07 0100 CSO CSO

area: 0130

location: S12W07

S9162 2023.11.20       S17W15            
13494 2023.11.20
2023.11.20
1 12 2 S17W03 0070 HSX CSO

area: 0160

13495 2023.11.20       N25W23           apparently the spots in  the northeastern part of AR S9156
S9166 2023.11.20       S33W17            
13500 2023.11.22
2023.11.23
10 29 19 S19E23 0470 DKC DKC beta-delta

location: S18E24

area: 0600

13499 2023.11.22
2023.11.23
9 29 16 S17W37 0060 CAI DAI beta-gamma

area: 0120

location: S17W36

13501 2023.11.22
2023.11.23
1 4 2 S09E32 0060 HSX CSO area: 0140
S9171 2023.11.22       N08W42            
13502 2023.11.22
2023.11.23
7 24 15 N15W14 0100 CAO DAO area: 0150

location: N14W11

S9173 2023.11.22   3 2 N11E04 0007   AXX  
13503 2023.11.23
2023.11.25
5 7 2 N21E45 0020 CRO DRO location: N21E48

area: 0040

13504 2023.11.25
2023.11.26
4 6 4 N14W65 0030 DRO DRO area: 0060

location: N11W67

S9178 2023.11.26   4 3 N17E21 0013   BXO    
S9179 2023.11.26   1 1 S22W47 0002   AXX    
S9180 2023.11.26   1   N38W03 0002   AXX    
S9181 2023.11.26   3   S19W23 0004   BXO    
Total spot count: 59 171 92  
Sunspot number: 169 331 232  (total spot count + 10 * number of spotted regions)
Weighted SN: 110 225 146  (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): 186 182 186  

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
2023.11 150.3 (1)   85.8 (2A) / 99.0 (2B) / 117.0 (2C) (137.8 projected max SC25, +2.6) (13.4)
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.

--------------------------------------------------------------------------------------

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.