Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 25, 2024 at 04:20 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 (January 1, 2024)
Solar cycle Solar cycles 23-25 (January 1, 2024) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (January 1, 2024) 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 (January 1, 2024) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (January 1, 2024) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (January  3, 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 to active on January 24 under the influence of weak CME effects. Solar wind speed at SOHO ranged between 416 and 503 km/sec. The high latitude magnetometer at Andenes recorded quiet to minor storm levels. The above 10 MeV proton flux was at background levels.

Solar flux density measured at 20h UT on 2.8 GHz was 172.0 - increasing 25.3 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 157.01. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 158.71 on June 27, 2023). The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 9.6). Three hour interval K indices: 43322001 (planetary), 32422221 (Boulder), 54311012 (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 11 active regions using 2K resolution (SN: 247) and in 10 active regions using 1K resolution (SN: 179) SDO/HMI images.

Region 13555 [S12W53] displayed few changes and was mostly quiet.
Region 13556 [N14W38] was quiet and stable.
Region 13557 [S23W25] was quiet and stable.
Region 13559 [N27W20] decayed significantly in the trailing spot section. The trailing spots are still close to the leader spots of AR S9346 and there is still a chance of a major flare.
Region 13560 [S10W20] was mostly quiet and stable. C1 flares: C1.7 @ 14:53 UT
Region 13561 [S16W60] decayed in the trailing spot section.
Region 13562 [S07W71] decayed slowly and quietly.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9346 [N28W08] decayed in the trailing spot section. M flares are still possible to interaction with AR 13559.
S9357 [S17W54] decayed losing spots and area. The magnetic delta structure in the trailing spot section lost area and extension. The region produced many C and M flares. C1 flares: C1.8 @ 15:47, C1.5 @ 16:57 UT
S9362 [S23E10] decayed slowly and quietly.
New region S9364 [S10E46] emerged with tiny spots.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
M1.0 00:38   S9357 GOES16  
C9.0 00:50   S9357 GOES16  
M1.2 01:07   S9357 GOES16  
M2.6 01:40   S9357 GOES16  
C2.3 03:07   13559 GOES16  
C2.2 03:20   13559 GOES16  
C3.9 04:37   S9357 GOES16  
C3.7 04:49   S9357 GOES16  
M1.4 05:43   S9357 GOES16  
C4.8 06:15   13561 GOES16  
C6.1 06:45   S9357 GOES16  
C5.2 06:57     GOES16  
C3.6 07:11     GOES16  
C2.7 07:27     GOES16  
C3.3 08:19   S9357 GOES16  
C3.7 09:06   13559 GOES16 simultaneous flare in AR 13555
C4.4 10:18 S17W50 S9357 GOES16  
C4.2 10:34 N29E02 S9346 GOES16  
C2.2 11:28   13559 GOES16  
C5.9 12:23 S17W54 S9357 GOES16  
C6.8 12:57 S17W52 S9357 GOES16  
C2.2 14:23   S9357 GOES16  
C2.4 15:58   S9357 GOES16  
C2.2 16:07   S9357 GOES16  
C2.9 18:15   13555 GOES16  
C5.9 19:43   S9357 GOES16  
C2.1 20:30   13561| GOES16  
M1.3 20:58   S9357 GOES16  
C5.7 21:40   13561 GOES16  
C2.1 23:16   13561 GOES16  
C2.3 23:27   13561 GOES16  
C2.2 23:42   13555 GOES16  

Coronal mass ejections (CMEs)

January 22: A partial halo CME was observed after a large filament eruption in the southwest quadrant after 09h UT. The CME could cause a disturbance on January 25.
January 23: Multiple partial halo CMEs were observed during the day due to flares in ARs S9346/13559 and S9357/13561. The CMEs could reach Earth on January 26.
January 24: No obviously Earth directed CMEs were observed.

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 negative polarity southern hemisphere coronal hole (CH1199) will likely become Earth facing on January 25-26. A negative polarity northern hemisphere coronal hole (CH1200) will likely become Earth facing on January 25-26, CH1200 is probably too far to the north to cause a disturbance.

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 to active on January 25-27 due to CME effects with a chance of minor storm intervals. Effects from CH1199 could reach Earth on January 28-31 and cause quiet to minor storm conditions.

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
13553 2024.01.13
2024.01.13
      N05W80         location: N02W76
13554 2024.01.13
2024.01.15
      N07W75          

location: N07W65

13555 2024.01.14
2024.01.15
4 9 5 S12W53 0060 CAO DAO

area: 0150

S9329 2024.01.15       S19W50            
13556 2024.01.15
2024.01.16
1 5 3 N16W44 0030 HRX CRO location: N14W38

area: 0015

13557 2024.01.16
2024.01.16
  6 1 S13W39 0010   BXO

location: S23W25

13561 2024.01.16
2024.01.19
18 27 18 S17W57 0200 DAC EAI beta-gamma

area: 0260

location: S16W60

S9333 2024.01.16       N11W55            
13559 2024.01.17
2024.01.18
20 27 18 N27W18 0480 FKI EKO

area: 0610

location: N27W20

SWPC includes AR S9346

13560 2024.01.17
2024.01.18
4 22 11 S10W21 0070 CAO DRI

location: S10W20

S9342 2024.01.18       S10W55            
S9343 2024.01.18       N22W21            
S9346 2024.01.19   17 9 N28W08 0100   DAI  
13562 2024.01.20
2024.01.20
1 4 2 S08W69 0010 AXX AXX

location: S07W71

S9353 2024.01.20       N26W54            
S9355 2024.01.20       N14W20            
S9357 2024.01.21   17 11 S17W54 0090   DAI beta-gamma
S9358 2024.01.21       N10W30            
S9360 2024.01.22       S09W47            
S9361 2024.01.22       S05W28            
S9362 2024.01.23   1   S23E10 0002   AXX  
S9363 2024.01.23       S49W19          
S9364 2024.01.24   2 1 S10E46 0007   AXX    
Total spot count: 48 137 79  
Sunspot number: 108 247 179  (total spot count + 10 * number of spotted regions)
Weighted SN: 76 173 115  (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): 119 136 143  

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
2022.05 133.8 136.8 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
2023.05 155.6 159.2 137.4 123.9 (+1.2) 10.67
2023.06 161.7 166.8 160.5 125.0 (+1.1)
(SC25 solar max candidate)
8.95
2023.07  176.4 182.2 160.0 (124.6 projected, -0.4) 8.15
2023.08  153.7 157.6 114.8 (124.1 projected, -0.5) 7.19
2023.09  154.4 156.0 134.2 (123.8 projected, -0.3) 14.26
2023.10  142.8 141.9 99.4 (124.6 projected, +0.8) 8.16
2023.11 153.5 150.2 105.4 (124.6 projected, +0.0) 12.20
2023.12 151.1 146.4 114.2 (121.2 projected, -3.4) 9.60
2024.01 170.1 (1)   105.6 (2A) / 136.4 (2B) / 159.4 (2C) (117.9 projected, -3.3) (5.5)
2024.02       (117.1 projected, -0.8)  
2024.03       (116.6 projected, -0.5)  
2024.04       (116.6 projected, +0.0)  
2024.05       (117.0 projected, -0.8)  
2024.06       (114.9 projected, -2.1)  

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 January 3, 2024

The relatively low solar activity during the last months of 2023 significantly increased the possibility that solar cycle 25 has already peaked. Whether the first peak in June 2023 will be the actual solar max will not be known for some time. Due to the relatively high solar activity early in 2023 it is unlikely there will be another solar max candidate, if at all, until at least May 2024. Both the northern and southern polar fields, as well as the averaged total field, have already reversed polarities.

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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.