Solar Terrestrial Activity Report

Activity chart

Last major update issued on November 2, 2024 at 07:15 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 (October 6, 2024)
Solar cycle Solar cycles 23-25 (November 1, 2024) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (November 1, 2024) Noon SDO sunspot count 1K image / 4K (*)
  Solar cycles 1-24 (August 1, 2020) POES auroral activity level [October 2009 - December 2012]
  Comparison of cycles 21-25 (November 1, 2024) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (November 1, 2024) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (October 13, 2024) 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
Calculating the Strength of Solar Cycle 25 Using 365-day Smoothing

Recent activity

The geomagnetic field was quiet on November 1. Solar wind speed at SOHO ranged between 423 and 575 km/sec, averaging 476 km/sec (-74 compared to the previous day). The high latitude magnetometer at Andenes recorded quiet to active levels. The above 10 MeV proton flux was at 4.9 pfu at the end of the day, slowly decreasing towards background levels.

Solar flux density measured at 20h UT on 2.8 GHz was 256.2 - decreasing 21.1 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 183.37. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 183.37 on May 3, 2024). The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 5.0). Three hour interval K indices: 22122010 (planetary), 21123220 (Boulder), 43121020 (Andenes).

The background x-ray flux is at the class C2 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 24 active regions using 2K resolution (SN: 484) and in 20 active regions using 1K resolution (SN: 306) SDO/HMI images.

AR 13868 [S11W72] was quiet and stable.
AR 13869 [S18W44] decayed slowly. A minor M class flare is possible.
AR 13873 [S16W34] decayed slowly and quietly.
AR 13874 [N24W71] was quiet and stable.
AR 13875 [N28W52] decayed in the intermediate and leading spot sections.
AR 13876 [S04W61] decayed, lost many spots and was mostly quiet.
AR 13877 [S16W17] was mostly quiet and stable.
AR 13878 [N16E14] decayed slowly. The magnetic delta configuration within the main penumbra are still present and there is a chance of a major flare.
AR 13879 [N15E36] was quiet and stable.
AR 13880 [S13E42] decayed slowly and quietly.
New AR 13881 [S09E26] emerged on October 30 and was numbered 2 days later by SWPC.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S10278 [S22W36] reemerged with tiny spots.
S10279 [N18W49] was quiet and stable.
S10292 [N17W01] reemerged with tiny spots.
S10295 [N11W30] was quiet and stable.
S10300 [S07E52] was quiet and stable.
S10303 [S09W62] produced several flares and developed slowly.
S10304 [S12E11] was quiet and stable.
S10305 [S16W09] was quiet and stable.
New region S10306 [N23W42] emerged with tiny spots before noon, then decayed slowly.
New region S10307 [N09E28] was observed with tiny spots in an old plage area.
New region S10308 [S05E81] rotated into view with a small spot.
New region S10309 [S22E30] was observed with tiny spots in an old plage area.
New region S10310 [S29W02] was observed with a tiny spot in an old plage area.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C7.3 00:16 N17E27 13878 GOES16  
C4.5 01:26   13875 GOES16  
C5.0 01:34   13875 GOES16  
M1.3 02:16 N17E27 13878 GOES16  
C3.5 03:36   S10303 GOES16  
C4.1 03:45   S10303 GOES16  
C4.0 04:12   13878 GOES16  
C3.9 04:58   13878 GOES16  
C3.6 05:39   13875 GOES16  
C3.1 06:32   13878 GOES16  
C4.9 07:20 behind southeast limb S10308 GOES16  
C5.2 07:39   S10303 GOES16  
C5.4 08:10 S09W51 S10303 GOES16  
C3.9 09:20   13878 GOES16  
C4.1 09:37   13878 GOES16  
C4.7 09:42   13878 GOES16  
M1.0/1F 10:13   S10303 GOES16  
C8.4 12:27   13880 GOES16 simultaneous flare in AR 13878
M1.3 12:52   S10303 GOES16  
C6.2 13:22   S10303 GOES16  
M2.0/1N 14:31   13878 GOES16  
C4.4 16:13   S10303 GOES16  
C6.3 16:33   S10303 GOES16  
C6.1 17:30   13877 GOES16  
C6.2 17:35   13878 GOES16  
C5.7 17:55   13878 GOES16  
C6.6 18:04   S10303 GOES16 simultaneous flare in AR 13869
C3.8 18:44   13878 GOES16  
C3.3 19:15   13878 GOES16  
C3.1 19:50   S10303 GOES16  
C4.6 20:11 S08W60 S10303 GOES16  
C4.5 20:26     GOES16  
C4.6 20:47   S10303 GOES16  
C4.4 21:06     GOES16  
C4.0 21:46     GOES16  
C3.6 23:16     GOES16  
C3.3 23:48     GOES16  

Coronal mass ejections (CMEs)

October 30 - November 1: No obviously Earth directed CMEs were observed.
October 29: A large filament in the southwestern quadrant erupted around noon. A partial halo CME was observed afterwards, and there is a slight chance components of the CME could reach Earth on November 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 positive polarity northern hemisphere coronal hole (CH1251) rotated across the central meridian on October 30-31. A positive polarity trans equatorial coronal hole (CH1252) was Earth facing on October 31 - November 1.

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

Forecast

The geomagnetic field is expected to be quiet to unsettled on November 2-4 due to effects from CH1251 and CH1252.

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
13868 2024.10.21
2024.10.21
1 1 1 S11W73 0120 HSX HSX

area: 0220

13869 2024.10.22
2024.10.23
14 35 15 S18W45 0260 DKC ESC

beta-gamma

location: S18W44

13875 2024.10.23
2024.10.24
13 28 11 N28W53 0170 DAI EAI

location: N28W52

13872 2024.10.23
2024.10.24
2     S17W36 0220 HAX      

merged with AR 13869 on 2024.10.31

13871 2024.10.24 10     S09W62 0180 DSI       was part of AR 13869, see AR S10303
13873 2024.10.24
2024.10.24
1 26 10 S10W30 0030 HAX DKO

location: S16W34

area: 0340

SWPC has the leader spot as AR 13872

S10278 2024.10.24   3 2 S22W28 0006   BXO    
S10279 2024.10.24   3 1 N18W49 0006   BXO  
13874 2024.10.24
2024.10.25
7 9 6 N25W72 0180 EAO EAO

location: N24W71

area: 0250

13876 2024.10.25
2024.10.25
7 14 7 S06W60 0180 DAO DAO

location: S04W61

area: 0230

SWPC mismatch between area and classification

S10284 2024.10.25       S15W21            
13877 2024.10.25
2024.10.27
1 6 2 S17W18 0010 AXX CRO

area: 0015

location: S16W17

13878 2024.10.26
2024.10.27
16 44 25 N16E10 0400 EKO EKC beta-gamma-delta

location: N16E14

area: 0520

S10292 2024.10.27   6 2 N17W03 0010   BXO    
13879 2024.10.28
2024.10.29
1 17 4 N15E36 0480 HHX CKO

area: 0830

S10295 2024.10.28   1 1 N11W30 0003   AXX  
S10296 2024.10.28       S01W17            
S10297 2024.10.29       S12W08            
13880 2024.10.29
2024.10.31
2 6 1 S13E41 0010 AXX BXO area: 0015

location: S13E42

S10299 2024.10.30       S12W00            
S10300 2024.10.30   2   S07E52 0003   AXX  
13881 2024.10.30
2024.11.01
5 14 6 S09E26 0050 DAI DRI area: 0110
S10303 2024.10.31   14 7 S09W62 0180   DAI beta-gamma

SWPC moved AR 13871 to this spot group on 2024.11.01

S10304 2024.10.31   2   S12E11 0003   AXX  
S10305 2024.10.31   5 1 S16W09 0010   BXO  
S10306 2024.11.01   2 2 N23W42 0006   BXO    
S10307 2024.11.01   2   N09E26 0005   AXX    
S10308 2024.11.01   1 1 S05E79 0010   HRX    
S10309 2024.11.01   2 1 S22E28 0003   AXX    
S10310 2024.11.01   1   S29W04 0002   AXX    
Total spot count: 80 244 106  
Sunspot number: 210 484 306  (total spot count + 10 * number of spotted regions)
Weighted SN: 150 313 175  (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): 231 266 245  

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
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
2023.03 157.2 155.6 123.3 121.1 (+3.3) 14.42
2023.04 145.4 146.4 97.6 122.9 (+1.8) 13.40
2023.05 155.6 159.2 137.4 124.2 (+1.3) 10.67
2023.06 161.7 166.8 160.5 125.3 (+1.1) 8.95
2023.07  176.4 182.2 160.0 124.6 (-0.7) 8.15
2023.08  153.7 157.6 114.8 124.3 (-0.3) 7.19
2023.09  154.4 156.0 134.2 124.0 (-0.3) 14.26
2023.10  142.8 141.9 99.4 124.8 (+0.8) 8.16
2023.11 153.5 150.2 105.4 127.8 (+3.0) 12.20
2023.12 151.1 146.4 114.2 129.4 (+1.6) 9.60
2024.01 164.6 159.3 126.0 131.1 (+1.7) 5.46
2024.02 172.5 168.3 123.0 136.8 (+5.7) 5.31
2024.03 154.4 152.9 103.7 141.3 (+4.5) 11.03
2024.04 161.3 162.6 136.5 144.4 (+3.1) 9.69
2024.05 187.7 191.9 171.7 (149.6 projected, +5.2) 23.56
(SC25 peak)
2024.06 184.3 190.2 164.2 (153.5 projected, +3.9) 10.24
2024.07 196.6 203.0 196.5  (156.4 projected, +2.9) 7.13
2024.08  246.1
(cycle peak)
252.2 215.5  (SC25 peak) (158.4 projected, +2.0) 15.96
2024.09 195.7 197.8 141.4 (161.1 projected, +2.7) 15.36
2024.10 221.0 219.6 166.3 (163.4 projected, +2.3) 19.0
2024.11 256.2 (1)   7 (2A) / 210 (2B) / 204.7 (2C) (161.8 projected, -1.6) (5)
2024.12       (158.7 projected, -3.1)  
2025.01       (154.4 projected, -4.3)  
2025.02       (147.6 projected, -6.8)  
2025.03       (142.8 projected, -4.8)  
2025.04       (139.8 projected, -3.0)  

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 October 27, 2024

Sunspot activity in October 2024 increased over September and looks to be headed for an SSN near 160. The average solar flux for October will become the second highest for a month during SC25. The above plot now displays the peak in 365d smoothed sunspot numbers in mid October. ISN has a peak on October 15, NOAA SN on October 14 while both the 1K and 2K SDO SN peaked on October 16. Assuming that the average sunspot number from October 2024 until April 14, 2025 becomes 150, we would be looking at a 365 days smoothed sunspot maximum of 164.5 centered on October 15. Should the average sunspot number for that period become 160 we would get a peak near 169.7.

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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.