Solar Terrestrial Activity Report

Activity chart

Last major update issued on November 2, 2023 at 08:05 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 to unsettled on November 1 due to lingering coronal hole effects. Solar wind speed at SOHO ranged between 423 and 507 km/sec. The high latitude magnetometer at Andenes recorded quiet to active levels.

Solar flux density measured at 20h UT on 2.8 GHz was 158.6 - increasing 2.5 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 155.89. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.1). Three hour interval K indices: 22322222 (planetary), 11433232 (Boulder), 44233214 (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: 262) and in 11 active regions using 1K resolution (SN: 180) SDO/HMI images.

Region 13472 [N20W39] developed slowly and produced a few flares. The region has minor polarity intermixing.
Region 13473 [N17W05] decayed slowly and quietly.
Region 13474 [S18W28] decayed in the trailing spot section and was mostly quiet. A weak magnetic delta structure formed in a small southern penumbra.
Region 13476 [S14W04] was quiet and stable.
Region 13477 [S14E67] was quiet and stable.
New region 13478 [N12E70] rotated into view on October 31 and was numbered by SWPC the next day.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9082 [N20W50] decayed slowly and quietly.
S9089 [N10W19] was quiet and stable.
S9107 [S21E19] was quiet and stable.
S9109 [N21E21] was quiet and stable.
New region S9111 [N24E45] was observed with a tiny spot.
New region S9112 [S17E00] was observed with tiny spots.
New region S9113 [S37E32] was observed with a tiny spot.

AR S9114 is rotating into view early on November 2 at S08 on the southeast limb. The region is unstable and could produce further M class flares.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C6.9 00:41 behind SE limb S9114 GOES16 LDE
C2.4 03:04   13474 GOES18  
C2.2 05:34 behind SE limb S9114 GOES18  
M1.1 06:26 behind SE limb S9114 GOES16 LDE
C3.0 09:08 behind SE limb S9114 GOES16  
C3.1 09:29 behind SE limb S9114 GOES16  
C3.0 11:47 behind SE limb S9114 GOES16  
M1.4 12:26 behind SE limb S9114 GOES16 LDE
C7.2 13:25   13478 GOES16  
C2.5 17:36   13474 GOES16  
C2.7 20:08   13472 GOES16  
C2.6 22:00   13472 GOES16  
C2.4 22:50   13472 GOES16  
C2.3 23:20 behind SE limb S9114 GOES16  

Coronal mass ejections (CMEs)

October 30+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 of 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 4-5.

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 2-4. Unsettled and active intervals are possible on November 3-4 should components of the October 31 CME reach Earth.

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
S9082 2023.10.22   1   N20W50 0002   AXX  
S9087 2023.10.25       N19W24            
13472 2023.10.25
2023.10.26
10 25 15 N20W39 0030 BXI DRI

beta-gamma

area: 0120

S9089 2023.10.25   8 4 N10W19 0015   AXX  
13473 2023.10.25
2023.10.26
7 23 7 N16W03 0020 BXO DRO area: 0040

location: N17W05

13474 2023.10.26
2023.10.27
23 37 28 S18W29 0430 DKI DKI beta-delta

location: S18W28

S9095 2023.10.26       N17W57            
S9097 2023.10.27       S14W21            
S9098 2023.10.27       S17W40            
13476 2023.10.28
2023.10.31
3 8 4 S15W04 0030 CRO DRO location: S14W04
S9103 2023.10.28       S23W28            
S9106 2023.10.30       N10E10            
S9107 2023.10.30   3 2 S21E19 0009   BXO  
S9108 2023.10.30       S15W17            
S9109 2023.10.31   5 3 N21E21 0020   CRO  
13478 2023.10.31
2023.11.01
1 1 1 N12E71 0010 HRX HRX area: 0030
13477 2023.10.31 1 6 4 S15E66 0160 HSX EKO area: 0400

location: S14E67

S9111 2023.11.01   1 1 N24E45 0002   AXX    
S9112 2023.11.01   3 1 N17E00 0005   BXO    
S9113 2023.11.01   1   S37E32 0002   AXX    
Total spot count: 45 132 70  
Sunspot number: 105 262 180  (total spot count + 10 * number of spotted regions)
Weighted SN: 66 167 105  (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): 116 144 144  

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
2023.11 158.6 (1)   3.5 (2A) / 105 (2B) / 115.5 (2C) (137.8 projected max SC25, +2.6) (8.1)
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.