Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 24, 2024 at 06:55 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 unsettled on January 23 under the influence of weak CME effects. Solar wind speed at SOHO ranged between 386 and 458 km/sec. The high latitude magnetometer at Andenes recorded quiet to minor storm levels. The above 10 MeV proton flux returned to background levels by the end of the day.

Solar flux density measured at 20h UT on 2.8 GHz was 180.3 - increasing 30.9 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 157.03. 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 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.3). Three hour interval K indices: 23211112 (planetary), 22211322 (Boulder), 34211135 (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 14 active regions using 2K resolution (SN: 348) and in 13 active regions using 1K resolution (SN: 254) SDO/HMI images.

Region 13549 [S21W80] was quiet and stable.
Region 13553 [N02W63] decayed slowly and quietly.
Region 13555 [S12W39] displayed few changes and was mostly quiet.
Region 13556 [N15W27] decayed slowly and quietly.
Region 13557 [S24W07] was quiet and stable.
Region 13559 [N26W05] has large leader and trailer spots, however, there are few significant intermediate spots. The potential for another major flare is primarily related to possible interaction with AR S9346.
Region 13560 [S10W07] decayed slowly and quietly.
Region 13561 [S16W45] is a compact region with many spots and some polarity intermixing. Major flares are possible due to interaction with nearby regions AR 13555 and S9357. The latitudinal separation between ARs 13561 and S9357 is minimal and the two regions could merge.
Region 13562 [S07W56] decayed slowly and quietly.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9346 [N28E05] decayed in the trailing spot section. M flares are still possible to interaction with AR 13559.
S9347 [S25W55] reemerged with a tiny spot.
S9357 [S17W42] is still a compact region with an elongated magnetic delta structure in the trailing spot section. A major flare is possible, also due to interaction with AR 13561.
New region S9362 [S24E23] emerged with tiny spots.
New region S9363 [S49W06] emerged with a tiny spot at a high latitude.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C4.6 00:06   13561 GOES16  
C8.9 00:15   S9357 GOES16  
C3.7 01:02   13561 GOES16  
C3.2 01:37   S9346 GOES16  
C5.4 03:02   S9346 GOES16  
M5.1 03:31   S9346 GOES16 simultaneous flare in AR S9357
C3.6 04:41   S9357 GOES16  
C3.2 05:18   13559 GOES16  
C2.8 06:13   S9357 GOES16  
C7.0 06:40   13561 GOES16  
C9.6 07:00 S19W35 13561 GOES16  
C6.9 07:56     GOES16  
M2.4 08:11   S9357 GOES16  
M2.3/1F 08:22 S19W37 S9357 GOES16 simultaneous flare in AR 13559
C8.1 08:48 behind northwest limb   GOES16  
C6.2 09:30   S9346 GOES16  
C3.7 10:04   S9357 GOES16  
C2.3 10:17   13561 GOES16  
C3.6 11:07   13559 GOES16  
C3.0 11:23   13561 GOES16  
C2.6 12:01   S9357 GOES16  
C2.7 12:49   S9357 GOES16  
M1.0 12:58   S9357 GOES16  
M1.0 13:08   S9346 GOES16  
C8.6 13:20   13559 GOES16  
C3.1 14:18   13561 GOES16  
C9.5 14:38   S9357 GOES16  
M1.3 14:59   S9357 GOES16  
C7.6 16:33   13559 GOES16  
M4.3 16:40   S9357 GOES16  
C7.3 17:39   13559 GOES16 incorrectly attributed by SWPC to smaller flare in AR 13561
C5.2 18:05   S9357 GOES16  
M1.0 18:28   13561 GOES16  
M1.1 18:44   13561 GOES16  
C9.1 19:35   S9357 GOES16  
M1.0 19:52   S9357 GOES16  
M1.0 20:01   S9357 GOES16  
C4.9 21:07   S9346 GOES16  
C2.9 23:20   13559 GOES16  

Coronal mass ejections (CMEs)

January 21: A partial halo CME was observed after a C4 flare in AR 13559, including filaments to the southeast, early in the day. There is a slight chance that the outer edge of the CME could reach Earth.
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.

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.

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 24-27 due to CME effects with a chance of minor storm intervals on January 26-27.

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
13549 2024.01.10
2024.01.12
1 1 1 S22W82 0170 HSX HHX

area: 0270

location: S21W80

13553 2024.01.13
2024.01.13
  1 1 N05W65 0002   AXX location: N02W63
13554 2024.01.13
2024.01.15
      N07W60          

location: N07W52

S9324 2024.01.13       S19W50            
13555 2024.01.14
2024.01.15
3 12 7 S12W38 0080 CAO CAO

area: 0220

location: S12W39

S9329 2024.01.15       S19W37            
13556 2024.01.15
2024.01.16
2 11 4 N16W29 0030 HRX CRO location: N15W27
13557 2024.01.16
2024.01.16
  6 3 S13W24 0010   BXO

location: S24W07

13561 2024.01.16
2024.01.19
18 39 29 S17W42 0220 DAC DAC beta-gamma

area: 0350

location: S16W45

S9333 2024.01.16       N11W42            
13559 2024.01.17
2024.01.18
20 44 22 N27W03 0520 FKI EKO beta-gamma

area: 0780

location: N26W05

SWPC includes AR S9346

13560 2024.01.17
2024.01.18
8 30 16 S10W06 0080 CAO DRI

location: S10W07

S9338 2024.01.17       N30W54          
S9340 2024.01.17       N11W53            
S9342 2024.01.18       S10W42            
S9343 2024.01.18       N22W08            
S9346 2024.01.19   30 15 N28E05 0180   DAI beta-gamma
S9347 2024.01.19   1   S23W52 0001   AXX    
S9348 2024.01.19       N12W57            
13562 2024.01.20
2024.01.20
1 7 4 S08W54 0030 CRO CAO

location: S07W56

S9351 2024.01.20       S20W36          
S9352 2024.01.20       S33W54            
S9353 2024.01.20       N26W41            
S9355 2024.01.20       N14W07            
S9357 2024.01.21   22 19 S17W42 0190   DAC beta-delta
S9358 2024.01.21       N10W17            
S9360 2024.01.22       S09W34          
S9361 2024.01.22       S05W15          
S9362 2024.01.23   3 2 S24E23          
S9363 2024.01.23   1 1 S49W06 0002   AXX    
Total spot count: 53 208 124  
Sunspot number: 123 348 254  (total spot count + 10 * number of spotted regions)
Weighted SN: 89 259 175  (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): 135 191 203  

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
2024.01 170.0 (1)   102.1 (2A) / 137.7 (2B) / 158.7 (2C) (117.9 projected, -3.3) (5.3)
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.