Solar Terrestrial Activity Report

Activity chart

Last major update issued on November 23, 2023 at 04:25 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 unsettled to minor storm on November 22 under the influence of effects from CH1187. Solar wind speed at SOHO ranged between 443 and 628 km/sec. The high latitude magnetometer at Andenes recorded unsettled to major storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 189.5 - increasing 62.6 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 156.74. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 30 (STAR Ap - based on the mean of three hour interval ap indices: 29.9). Three hour interval K indices: 45543443 (planetary), 34543332 (Boulder), 45633354 (Andenes).

The background x-ray flux is at the class C4 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 17 active regions using 2K resolution (SN: 356) and in 15 active regions using 1K resolution (SN: 240) SDO/HMI images.

Region 13488 [N29W25] lost the leader spots and was quiet.
Region 13489 [S13E05] decayed substantially and produced several C flares.
Region 13491 [N10E32] was quiet and stable.
Region 13492 [N19E37] produced several C flares. New spots to the southeast were split off into a separate group.
Region 13493 [S12E45] was mostly quiet and stable.
Region 13494 [S17E50] was mostly quiet and stable.
Region 13496 [N07E08] was quiet and stable.
Region 13497 [N18E23] decayed slowly and quietly.
Region 13498 [S11W40] decayed slowly and quietly.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9156 [N22E26] developed further and has a weak magnetic delta structure in a southern penumbra. A minor M class flare is possible.
S9164 [S08W42] decayed early in the day, then developed slowly.
New region S9168 [S18E77] rotated into view as a compact, complex region with major flare potential. Many C flares were recorded from this region.
New region S9169 [S17E18] emerged during the latter half of the day with several spots.
New region S9170 [S09E85] rotated partly into view with a mature spot.
New region S9171 [N08E11] emerged to the east of AR 13496.
New region S9172 [N15E41] developed quickly and produced many C flares. The region has a magnetic delta structure in a leading penumbra and could produce M class flares.
New region S9173 [N11E59] was observed with tiny spots in an old plage area.

An active region just behind the northeast limb was the source of an M1.4 flare at 03:37 UT on November 23.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C7.5 01:11 N21E48 13492 GOES18  
C4.3 01:21   S9172 GOES18  
C3.6 01:36   S9172 GOES18  
C3.5 01:52   S9172 GOES18  
C3.6 02:16   13492 GOES18  
C3.2 04:01   13492 GOES18  
C3.1 04:48   13492 GOES18  
C4.3 05:27   13492 GOES18  
C3.4 06:05 southeast limb S9168 GOES18  
C8.9 06:28 N13E51 S9172 GOES18  
C3.4 06:57   13492 GOES18  
C3.3 07:33   S9156 GOES18  
C4.3 07:40   S9172 GOES18  
C3.7 07:58 southeast limb S9168 GOES18  
C3.8 08:36   13492 GOES18  
C3.8 09:28   S9172 GOES18  
C4.4 09:47   S9172 GOES18  
C4.2 10:04   13489 GOES18 simultaneous flare in AR S9172
C3.6 10:39   S9168 GOES18 simultaneous flare in AR 13492
C3.4 11:11   S9168 GOES18  
C4.8 11:58   S9168 GOES18  
C4.6 12:15   S9168 GOES18  
C4.6 12:31   13489 GOES18  
C3.9 13:05   13489 GOES18  
C4.3 14:07   S9172 GOES18  
C4.3 14:46   S9172 GOES18  
C4.3 15:50   S9172 GOES18  
C4.9 16:45   S9172 GOES18  
C4.4 17:20   13492 GOES18  
C3.5 17:54   13492 GOES18  
C3.5 18:56   S9168 GOES18  
C4.1 19:02   13489 GOES18  
C6.1 20:26   S9168 GOES18  
C4.4 22:31   13492 GOES18  
C4.8 23:00   S9156 GOES18  
C3.4 23:30   13492 GOES18  
C6.3 00:03   S9172 GOES18  

Coronal mass ejections (CMEs)

November 20-21: 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 well defined positive polarity northern hemisphere coronal hole (CH1187) was Earth facing on November 18. A positive polarity northern hemisphere coronal hole (CH1189) will be 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 unsettled on November 23 due to decreasing effects from CH1187. Quiet conditions are likely on November 24. If the Nov.22 CME reaches Earth, we could see unsettled to active conditions on November 25. Effects from CH1189 could cause quiet to minor storm conditions on November 26-27.

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       N25W37            
13488 2023.11.14
2023.11.14
  4   N31W32 0008   AXX

location: N29W29

S9149 2023.11.16       S08W36            
13489 2023.11.16
2023.11.17
14 29 13 S16E04 0220 CAI CAO

location: S13E05

S9151 2023.11.16       S24W19            
S9152 2023.11.16       S14W53            
S9153 2023.11.17       N22W50            
S9154 2023.11.17       S18W51            
13497 2023.11.18
2023.11.20
  8 2 N16E22 0030   CRO location: N18E23

SWPC has moved AR 13490 back and forth over the last days and has finally decided that what was AR 13497 is now the southern part of 13490 to them

S9156 2023.11.18   24 8 N22E26 0290   DAC beta-delta

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

13490 2023.11.18 9     N20E22 0150 DAC        
S9157 2023.11.18       N13W18            
13492 2023.11.18
2023.11.20
33 41 27 N18E36 0310 EKC EKI beta-gamma

area: 0510

13491 2023.11.18
2023.11.19
1 1 1 N13E27 0040 HSX HSX location: N10E32

area: 0090

SWPC location is way off

13496 2023.11.19
2023.11.20
2 4 2 N09E08 0010 BXO BXO location: N07E08
13493 2023.11.20
2023.11.20
3 4 1 S12E43 0040 CSO CSO

location: S12E45

area: 0150

S9162 2023.11.20       S17E37          
13494 2023.11.20
2023.11.20
12 2 2 S16E50 0030 HSX HAX

location: S17E50

area: 0150

SWPC spot count must be a typo

13495 2023.11.20 2     N27E31 0030 HRX       apparently the spots in  the northeastern part of AR S9156
S9164 2023.11.20   8 3 S08W42 0040   DRO  
S9165 2023.11.20       N47W52            
S9166 2023.11.20       S33E35          
13498 2023.11.21
2023.11.21
8 7 4 S11W40 0050 DAO DAO

area: 0090

S9167 2023.11.21       S09W45          
S9168 2023.11.22   12 5 S18E77 0390   DKC   beta-delta
S9169 2023.11.22   16 5 S17E18 0100   DRI    
S9170 2023.11.22   1 1 S09E85 0050   HSX    
S9171 2023.11.22   1 1 N08E11 0010   HRX    
S9172 2023.11.22   22 15 N15E41 0350   DAC   beta-delta
S9173 2023.11.22   2   N11E59 0002   AXX    
Total spot count: 84 186 90  
Sunspot number: 174 356 240  (total spot count + 10 * number of spotted regions)
Weighted SN: 127 258 162  (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): 191 196 192  

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
2023.11 144.5 (1)   62.2 (2A) / 84.8 (2B) / 102.7 (2C) (137.8 projected max SC25, +2.6) (13.1)
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.