Solar Terrestrial Activity Report

Activity chart

Last major update issued on November 1, 2024 at 04:00 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 at quiet to active levels on October 31. A solar wind transient was observed beginning near 17h UT at ACE and the total field of the IMF reached 10 nT later in the day. Solar wind speed at SOHO ranged between 443 and 630 km/sec, averaging 550 km/sec (+10 compared to the previous day). The high latitude magnetometer at Andenes recorded quiet to major storm levels. The above 10 MeV proton flux was at 13 pfu at the end of the day.

Solar flux density measured at 20h UT on 2.8 GHz was 269.9 - decreasing 21.1 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 183.10. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 183.10 on May 2, 2024). The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.3). Three hour interval K indices: 11111234 (planetary), 11112333 (Boulder), 21011336 (Andenes).

The background x-ray flux is at the class C3 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 17 active regions using 2K resolution (SN: 476) and in 15 active regions using 1K resolution (SN: 291) SDO/HMI images.

AR 13868 [S11W59] was quiet and stable.
AR 13869 [S18W32] decayed further and merged with AR 13872. A small magnetic delta configuration formed.
AR 13873 [S16W21] decayed slowly and quietly.
AR 13874 [N24W58] decayed slowly and quietly.
AR 13875 [N28W40] developed further and has minor polarity intermixing.
AR 13876 [S04W46] decayed slowly. The spots immediately to the south of this region were split off into a separate spot group.
AR 13877 [S15W04] was mostly quiet and stable.
AR 13878 [N16E26] developed further and has magnetic delta configurations both in the northwestern and eastern part of the largest penumbra. Further major flares are likely.
AR 13879 [N14E49] was quiet and stable.
New AR 13880 [S13E55] rotated into view on October 28 and was numbered by SWPC 2 days later.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S10279 [N13W43] decayed slowly and quietly.
S10295 [N11W17] was quiet and stable.
S10300 [S09E59] decayed slowly and quietly.
S10301 [S09E39] developed slowly and quietly.
New region S10303 [S09W48] was split off from AR 13876 as development continued. The spot group has polarity intermixing. Minor M class flares are possible.
New region S10304 [S11E23] was observed with tiny spots in an old plage area.
New region S10305 [S14E07] was observed with tiny spots in an old plage area.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C9.3 00:51 S09W31 S10303 GOES16  
C4.2 01:51   S10303 GOES16  
M1.0 02:52 N15E36 13878 GOES16  
M1.0 03:30 N15E36 13878 GOES16  
C5.1 04:28   13878 GOES16  
C5.6 05:11   S10303 GOES16 simultaneous flare in AR 13878
C6.7 05:54   13878 GOES16 simultaneous flare in AR S10303
C4.9 06:25   13878 GOES16  
C3.4 07:35   13878 GOES16  
C6.2 08:31   S10303 GOES16  
C5.5 08:45   13878 GOES16  
C7.6 09:04   S10303 GOES16  
C7.1 09:29   13878 GOES16  
M1.4/1F 09:37 N17E36 13878 GOES16  
M1.2 09:43   13878 GOES16  
M1.1 09:50   13878 GOES16  
C9.2 09:55   13878 GOES16  
C6.4 10:23   13878 GOES16  
C9.1 10:27   13878 GOES16  
C7.4 10:35   13878 GOES16  
C3.4 11:31   S10303 GOES16  
C3.2 12:05   S10303 GOES16  
M2.4/1N 12:54 N27W35 13875 GOES16 simultaneous flare in AR 13877
C5.1 13:34   13878 GOES16  
M1.2 13:59   S10303 GOES16  
C6.0 14:37   S10303 GOES16 simultaneous flare in AR 13875
C3.5 15:19   13876 GOES16  
C3.2 16:02   S10303 GOES16  
C4.1 16:58   13876 GOES16  
C4.3 17:17   13878 GOES16  
C3.5 18:16   S10303 GOES16  
C4.7 18:29   S10303 GOES16  
C4.8 18:36   S10303 GOES16  
M1.0/2N 19:07   S10303 GOES16  
C4.9 19:37   13878 GOES16  
C6.3 20:25   13876 GOES16  
M4.6 21:10 N18E24 13878 GOES16  
X2.0 21:20   13878 GOES16  
M9.4 21:54   13878 GOES16  
M2.7 22:48   S10303 GOES16  

Coronal mass ejections (CMEs)

October 30-31: 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) will be 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 very poor. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet to unsettled on November 1-4, on Nov. 2-3 due to effects from CH1251 and on November 3-4 with effects from CH1252 dominating.

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
13865 2024.10.19
2024.10.20
      S22W86            
13866 2024.10.20
2024.10.21
      S12W78            
13868 2024.10.21
2024.10.21
1 1 1 S11W59 0150 HSX HSX

area: 0220

13869 2024.10.22
2024.10.23
12 38 23 S18W33 0260 DKC ESC

beta-gamma-delta

location: S18W32

13875 2024.10.23
2024.10.24
15 26 13 N28W41 0150 DAI DAI beta-gamma

location: N28W40

area: 0230

S10272 2024.10.23       N18W57            
13872 2024.10.23
2024.10.24
6     S17W24 0240 DKO    

merged with AR 13869 on 2024.10.31

13871 2024.10.24       S09W50           part of AR 13869
13873 2024.10.24
2024.10.24
4 47 17 S12W15 0040 HAX DKO

location: S16W21

area: 0380

SWPC data has the leader spot as part of AR 13872

S10278 2024.10.24       S22W20          
S10279 2024.10.24   1   N13W43 0001   AXX  
13874 2024.10.24
2024.10.25
7 19 9 N25W60 0200 EAI EAI

location: N24W58

area: 0250

S10282 2024.10.25       N11W49            
13876 2024.10.25
2024.10.25
18 40 14 S06W46 0200 DKI DAI beta-gamma

location: S04W46

area: 0280

SWPC mismatch between area and classification

S10284 2024.10.25       S15W08            
13877 2024.10.25
2024.10.27
1 14 5 S16W04 0010 AXX CRO

area: 0025

location: S15W04

13878 2024.10.26
2024.10.27
11 53 32 N16E23 0400 EKI EKC beta-gamma-delta

location: N16E26

area: 0560

S10290 2024.10.26       S21W59            
S10291 2024.10.27       N24W56            
S10292 2024.10.27       N16E06          
13879 2024.10.28
2024.10.29
1 11 5 N15E50 0570 HHX CKO location: N14E49

area: 0870

S10295 2024.10.28   5 1 N11W17 0010   AXX  
S10296 2024.10.28       S01W04            
S10297 2024.10.29       S12E05            
13880 2024.10.29
2024.10.31
1 9 6 S13E55 0010 AXX CRO area: 0025
S10299 2024.10.30       S12E13          
S10300 2024.10.30   2   S09E59 0003   AXX  
S10301 2024.10.30   7 2 S09E39 0015   BXO  
S10303 2024.10.31   19 10 S09W48 0150   DAI   beta-gamma
S10304 2024.10.31   6 1 S11E23 0012   AXX    
S10305 2024.10.31   8 2 S14E07 0015   AXX    
Total spot count: 77 306 141  
Sunspot number: 187 476 291  (total spot count + 10 * number of spotted regions)
Weighted SN: 147 372 207  (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): 206 262 233  

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 (1)   0 (2A/2B) / 203.9 (2C) (161.8 projected, -1.6) ()
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.