Solar Terrestrial Activity Report

Activity chart

Last major update issued on November 29, 2023 at 06:20 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 on November 28, weakly under the influence of effects from CH1189. Solar wind speed at SOHO ranged between 403 and 495 km/sec. The high latitude magnetometer at Andenes recorded quiet to active levels.

Solar flux density measured at 18h UT on 2.8 GHz was 181.5 - increasing 22.9 over the previous solar rotation (the measurement at 20h UT was flare enhanced). (Centered 1 year average SF at 1 AU - 183 days ago: 157.91. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.4). Three hour interval K indices: 21222212 (planetary), 12212221 (Boulder), 33111325 (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: 308) and in 15 active regions using 1K resolution (SN: 227) SDO/HMI images.

Region 13492 [N19W43] decayed slowly and quietly.
Region 13493 [S12W34] decayed slowly and quietly.
Region 13494 [S17W28] decayed slowly and quietly.
Region 13499 [S17W59] decayed slowly and was mostly quiet until near the end of the day when a C8 flare was observed. C1 flares: C1.9 @ 05:17 UT
Region 13500 [S18W02] developed slightly gaining spots and area. The region has significant polarity intermixing and further major flares are possible. C1 flares: C1.9 @ 13:41, C1.9 @ 16:18 UT
Region 13501 [S09E07] was quiet and stable.
Region 13502 [N14W38] decayed before noon, then developed slightly after noon as new flux emerged to the north of the main penumbral areas. No spots have mature penumbra. C1 flares: C1.8 @ 05:29, C1.7 @ 16:53, C1.8 @ 18:14 UT
Region 13503 [N22E22] was quiet and stable.
New region 13505 [S17E81] rotated into view on November 27 and was numbered the next day by SWPC.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9156 [N21W56] decayed further and was quiet.
S9173 [N14W18] was quiet and stable.
S9178 [N16W09] developed slowly and quietly.
New region S9184 [S14E79] rotated into view with a mature spot.
New region S9185 [N08E81] rotated into view with a large, mature spot.
New region S9186 [S09E27] emerged with a tiny spot.
New region S9187 [S27W24] was observed with tiny spots in an old plage area.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C4.3 00:44   13500 GOES18  
C2.1 04:48   13500 GOES18  
C2.0 15:41   13500 GOES16  
C2.0 16:29   13504 GOES16  
C2.2 17:53   13502 GOES16  
C2.3 19:15   13500 GOES16  
M3.4 19:32 western part of the region 13500 GOES18 moderate type II radio sweep. Full halo CME. Simultaneous flare in AR 13502
M9.8 19:50 large area including all of the region 13500 GOES18 weak type II radio sweep. Bright full halo CME
C7.3 21:32   13500 GOES18  
C8.1 23:31   13499 GOES18  

Coronal mass ejections (CMEs)

November 26: No obviously Earth directed CMEs were observed.
November 27: Several CMEs were observed during the day. The first one involved a filament eruption 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 point to near the equator in the northwestern part of the filament channel. Coronal dimming was observed. A partial halo CME was observed and could reach Earth early on November 30. The second filament eruption began near 18:17 UT and occurred in the northeastern quadrant. The eruption affected areas as far south as AR 13500 and resulted in at least a partial halo CME, maybe a faint full halo CME. This CME is likely to reach Earth on December 1. The third filament eruption also occurred in the northeastern quadrant and further east than the previous eruption. This event began near 23:07 UT in SDO/AIA imagery. A partial halo CME was observed after this event and could influence Earth on December 1.
November 28: A full halo CME was observed after the M3.4 flare in AR 13500 at 19:32 UT. Another and brighter symmetrical full halo CME was observed after the major M9.8 flare at 19:50 UT. The CMEs are expected to merge. The combined CME is likely directed straight at Earth. Minor to severe storm conditions are likely on December 1-2.

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 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 on November 29. Late on November 29 or early on November 30 the first of the November 27 CMEs could reach Earth and cause unsettled to minor storm conditions. The second CME will likely arrive later in the day or early on December 1 and could increase the disturbance to major storm levels. The last of the Nov.27 CMEs may have an Earth directed component that could reach us on December 1. The November 28 CMEs are expected to combine and reach Earth on December 1 resulting in minor to severe storm conditions that day and on December 2. Quiet to unsettled conditions are likely on December 3. Effects from CH1190 could cause unsettled to minor storm conditions 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
13489 2023.11.16
2023.11.17
      S15W78        

location: S14W75

13497 2023.11.18
2023.11.20
      N17W63           location: N18W54
S9156 2023.11.18   6 3 N21W56 0012   AXX  
13490 2023.11.18 1     N22W56 0005 AXX        
13492 2023.11.18
2023.11.20
3 10 5 N19W47 0070 DSO CSO

area: 0240

location: N19W43

13491 2023.11.18
2023.11.19
      N11W52           location: N10W47
13496 2023.11.19
2023.11.20
      N09W77           location: N07W70
13493 2023.11.20
2023.11.20
2 8 6 S13W36 0010 CSO CSO

area: 0070

location: S12W34

S9162 2023.11.20       S17W41            
13494 2023.11.20
2023.11.20
1 1 1 S17W29 0010 HSX HSX

area: 0120

location: S17W28

bad area data from SWPC on this and AR 13493

13495 2023.11.20       N25W52           apparently spots in  the northeastern part of AR S9156
S9166 2023.11.20       S33W43            
13500 2023.11.22
2023.11.23
12 61 33 S19W05 0320 DKC DAC beta-gamma

location: S18W02

area: 0600

13499 2023.11.22
2023.11.23
4 9 4 S17W59 0010 BXO CRO

area: 0025

13501 2023.11.22
2023.11.23
1 5 2 S09E04 0020 HSX CSO area: 0120

location: S09E07

again bad area data from SWPC

13502 2023.11.22
2023.11.23
4 19 9 N14W37 0020 CAO DRI area: 0110

location: N14W38

bad area data from SWPC

S9173 2023.11.22   5 3 N14W18 0012   AXX  
13503 2023.11.23
2023.11.25
1 8 2 N15E18 0010 HRX CRO location: N22E22

area: 0030

SWPC location is way off

S9178 2023.11.26   10 5 N16W09 0030   CRO  
S9180 2023.11.26       N38W29            
S9181 2023.11.26       S19W49            
13505 2023.11.27
2023.11.28
1 1 1 S17E69 0020 HAX HSX area: 0070
S9183 2023.11.28       N44W48          
S9184 2023.11.28   1 1 S14E79 0190   HSX    
S9185 2023.11.28   1 1 N08E81 0320   HHX    
S9186 2023.11.28   1 1 S09E27 0002   AXX    
S9187 2023.11.28   2   S27W24 0002   AXX  

 

Total spot count: 30 148 77  
Sunspot number: 130 308 227  (total spot count + 10 * number of spotted regions)
Weighted SN: 73 205 124  (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): 143 169 182  

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
2023.11 152.5 (1)   95.4 (2A) / 102.2 (2B) / 122.3 (2C) (137.8 projected max SC25, +2.6) (12.9)
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.