Solar Terrestrial Activity Report

Activity chart

Last major update issued on November 3, 2023 at 08:50 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 (October 8, 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 quiet on November 2. Solar wind speed at SOHO ranged between 378 and 487 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 158.4 - increasing 3.1 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 155.96. 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: 5.6). Three hour interval K indices: 22112111 (planetary), 23222211 (Boulder), 33112123 (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 13 active regions using 2K resolution (SN: 276) and in 12 active regions using 1K resolution (SN: 183) SDO/HMI images.

Region 13472 [N20W51] decayed slowly and quietly.
Region 13473 [N17W21] decayed slowly and was mostly quiet.
Region 13474 [S18W42] lost the magnetic delta with continued slow decay in the trailing spot section. Further M class flares are possible.
Region 13476 [S16W15] decayed slowly and quietly.
Region 13477 [S14E54] was quiet and stable.
Region 13478 [N12E57] decayed slowly and quietly.
New region 13479 [N20E08] emerged on October 31 and was numbered by SWPC 2 days later.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9089 [N11W31] decayed slowly and quietly.
S9106 [N12W03] reemerged with tiny spots.
S9107 [S21E06] developed slowly and quietly.
New region S9114 [S08E80] rotated into view. This region and AR 13474 were the most active on the visible disk. A major flare is possible.
New region S9115 [N20E76] rotated into view with a small spot.
New region S9116 [N00E08] emerged at the equator with a tiny spot and with a southern hemisphere polarity orientation.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.1 01:10   13474 GOES16  
C3.9 01:58 S15W32 13474 GOES16  
C4.9 05:14   13474 GOES16  
C4.9 05:22   S9114 GOES16  
C6.4 06:25   S9114 GOES16  
C2.1 07:23   13474 GOES16  
C2.0 08:31   S9114 GOES16  
C3.9 11:19   S9114 GOES16  
C2.2 12:11 S19W31 13474 GOES16  
M1.6 12:22 S19W31 13474 GOES16  
C2.1 13:14   S9114 GOES16  
C2.0 14:25   S9114 GOES16  
M1.0 19:21   S9114 GOES16  
C4.2/1F 22:50 N16W17 13473 GOES16  

Coronal mass ejections (CMEs)

November 3: A CME was observed following a large (about 50 degrees long) filament eruption in the northwestern quadrant (from the central meridian and westwards) early in the day. The CME could reach Earth on October 6.
November 2: Several CMEs were observed during the day. The most interesting one was associated with an eruption in the northeastern quadrant starting near 02:30 UT in SDO/AIA imagery. At least a partial halo CME was observed after this event and there's a fair chance CME components could reach Earth on November 5.
November 1: No obviously Earth directed CMEs were observed.
October 31: A CME was observed starting at 22:12 UT in LASCO C2 imagery after a filament eruption in the central southern hemisphere. The core of the CME was observed off the south pole, weak extensions were seen off the southwest limb. Analysis was somewhat complicated due to a CME off the east limb (from a source just behind the southeast limb) that started at 21:12 UT in LASCO imagery, and it is uncertain if components of the CME related to the filament eruption will reach Earth. The is a minor chance of weak CME effects on November 3-4.

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 and well defined negative polarity trans equatorial coronal hole (CH1183) will likely become Earth facing on November 4-6.

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 on November 3-4. Unsettled and active intervals are possible on November 3-4 should components of the October 31 CME reach Earth. Quiet to minor storm conditions are possible on November 5 should the November 2 CME become geoeffective. Unsettled to major storm is possible on November 6 due to the Nov.3 CME. Quiet to major storm is possible on November 7-8 due to effects from CH1183.

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
S9087 2023.10.25       N19W37            
13472 2023.10.25
2023.10.26
11 22 6 N20W51 0060 DAI DRI  
S9089 2023.10.25   7 1 N11W31 0010   AXX  
13473 2023.10.25
2023.10.26
1 18 7 N16W18 0010 AXX CRO area: 0030

location: N17W21

13474 2023.10.26
2023.10.27
20 36 22 S18W42 0400 DKC EHI beta-gamma
S9097 2023.10.27       S14W34            
S9098 2023.10.27       S17W53            
13476 2023.10.28
2023.10.31
2 3 1 S15W19 0010 BXO BXO location: S16W15

area: 0007

S9103 2023.10.28       S23W41            
S9106 2023.10.30   7 1 N12W03 0010   AXX    
S9107 2023.10.30   8 5 S21E06 0030   CRO  
S9108 2023.10.30       S15W30            
13479 2023.10.31
2023.11.02
4 14 5 N22E08 0020 CAO DRO area: 0030
13478 2023.10.31
2023.11.01
1 4 2 N12E57 0020 HRX CRO  
13477 2023.10.31 4 15 7 S15E53 0300 CKO EKO area: 0400

location: S14E54

S9111 2023.11.01       N24E32          
S9112 2023.11.01       N17W13          
S9113 2023.11.01       S37E19          
S9114 2023.11.02   10 5 S08E80 0380   EKC    
S9115 2023.11.02   1 1 N20E76 0010   HRX    
S9116 2023.11.02   1   N00E08 0001   AXX    
Total spot count: 43 146 63  
Sunspot number: 113 276 183  (total spot count + 10 * number of spotted regions)
Weighted SN: 76 194 111  (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): 124 152 146  

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) 8.2
2023.11 158.5 (1)   7.3 (2A) / 109.0 (2B) / 115.0 (2C) (137.8 projected max SC25, +2.6) (6.9)
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.