Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 9, 2025 at 04:20 UT.
Reports from November 27 onwards will be updated when archived SDO imagery becomes available.

Sunspot data based on alternative image sources from November 27, 2024 until January 8, 2025. Normal SDO spot counts will resume on January 9.

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, 2025)
Solar cycle Solar cycles 23-25 (January 1, 2025) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (January 1, 2025) 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 (January 1, 2025) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (January 1, 2025) 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 January 8. Solar wind speed at SOHO ranged between 453 and 539 km/sec, averaging 472 km/sec (-62 km/sec compared to the previous day). The high latitude magnetometer at Andenes recorded quiet to minor storm levels. The above 10 MeV proton flux was at  background levels at the end of the day.

Solar flux density measured at 20h UT on 2.8 GHz was 160.2 - decreasing 0.7 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 191.38. In comparison SC24 peaked on June 28, 2014 at 145.50 while SC23 peaked on February 23, 2002 at 198.15. Current SC25 peak: 191.44 on July 8, 2024 (given a base solar flux level of 65, this is +57.07% compared to the SC24 peak and -5.04% compared to the SC23 peak). The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 7.6). Three hour interval K indices: 43201231 (planetary), 22201312 (Boulder), 53201322 (Andenes).

The background x-ray flux is at the class B9 level (GOES 18).

AR 13943 [S15W45] decayed slowly and quietly.
AR 13945 [S09W35] decayed slowly and quietly.
AR 13947 [N11W10] produced a few low level C flares. C1 flares: C1.9 @ 06:04, C1.8 @ 20:59 UT
AR 13948 [N23W43] reemerged with a few spots.
AR 13950 [S18E10] was quiet and stable.
AR 13952 [N18W55] was quiet and stable.
New AR 13953 [N20W16] emerged on January 7 and was numbered by SWPC the next day.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
T163 [N14W39] was quiet and stable.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.4 01:44     GOES16  
C2.2 02:16     GOES16  
C3.8 04:03 S07W18 13945 GOES16  
C9.8 06:37   13950 GOES16  
C2.4 09:10 S16W22 13951 GOES16  
C2.3 10:05 N12W03 13947 GOES16  
C2.1 15:12   13950 GOES16  

C1 flares: C1.6 @ 04:52, C1.4 @ 08:01, C1.2 @ 16:41, C1.2 @ 19:17 UT

Coronal mass ejections (CMEs)

January 6-8: No obviously Earth directed CMEs.

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]

No obvious coronal holes are currently in or near Earth facing locations.

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 fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be mostly quiet on January 9-11.

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
STAR SWPC STAR Current Previous
2K 1K
13942 2024.12.27
2024.12.29
      S13W86           was T150
13943 2024.12.29
2024.12.30
2   1 S17W47 0030 CSO HAX     was T154

location: S15W45

13944 2024.12.30
2024.12.31
2     S13W73 0010 BXO      

location: S15W70

T157 2024.12.31       S18W37            
13951 2024.12.31
2025.01.04
      S13W28           was T158

location: S14W26

13945 2024.12.31
2025.01.01
6   7 S10W37 0030 CRO CRO    

was T159

location: S09W35

13948 2025.01.01
2025.01.02
1   1 N16W40 0010 AXX AXX     was T161

actual location: N23W43

SWPC originally assigned this AR to spots at N23E36
When those spots disappeared SWPC chose to move the region to the location of AR T163, then located 9 degrees further south and 10 degrees further east. The original AR 13948 reemerged on January 8.

13947 2025.01.01
2025.01.02
12   21 N12W09 0370 EKC EKC     beta-gamma

was T162

area: 0580

location: N11W10

T163 2025.01.02     1 N14W39 0010   HRX      
T164 2025.01.02       S34W39            
T165 2025.01.02       S10W41            
13950 2025.01.03
2025.01.04
3   5 S18E09 0070 CSO CAO     was AR T166

location: S18E10

area: 0160

T167 2025.01.03       N08W13            
13952 2025.01.04
2025.01.04
1   1 N19W57 0010 AXX HRX     location: N18W55
T168 2025.01.06       S09W55            
13953 2025.01.07
2025.01.08
6   7 N20W18 0010 BXI DRO     was AR T169

location: N20W16

Total spot count: 33   44  
Sunspot number: 113   124  (total spot count + 10 * number of spotted regions)
Weighted SN: 56   73  (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): 124   99  

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
2023.04 145.4 146.4 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
2023.11 153.5 150.2 105.4 127.9 (+3.1) 12.20
2023.12 151.1 146.4 114.2 129.5 (+1.6) 9.60
2024.01 164.6 159.3 126.0 131.1 (+1.6) 5.46
2024.02 172.5 168.3 123.0 136.9 (+5.8) 5.31
2024.03 154.4 152.9 103.7 141.4 (+4.5) 11.03
2024.04 161.3 162.6 137.0 144.4 (+3.1) 9.69
2024.05 187.7 191.9 172.1 149.1 (+4.7) 23.56
(SC25 peak)
2024.06 184.3 190.2 164.1 152.7 (+3.6) 10.24
2024.07 196.6 203.0 196.5  (155.4 projected, +2.7) 7.13
2024.08  246.1
(cycle peak)
252.2 215.5  (SC25 peak) (157.3 projected, +1.9) 15.96
2024.09 195.7 197.8 141.4 (159.9 projected, +2.2) 15.36
2024.10 221.0 219.6 166.3 (161.2 projected, +2.3) 18.99
2024.11 199.6 195.3 152.5 (158.6 projected, -2.6) 9.33
2024.12 197.3 191.2 154.5 (154.2 projected, -4.4) 8.5
2025.01 190.1 (1)    41.1 (2A) / 159.3 (2B) / - (2C) (148.0 projected, -6.2) (24.1)
2025.02       (139.4 projected, -8.6)  
2025.03       (133.0 projected, -6.4)  
2025.04       (128.3 projected, -4.7)  
2025.05       (122.6 projected, -5.7)  
2025.06       (116.8 projected, -5.8)  

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 December 30, 2024

Sunspot activity increased again during the second half of December 2024, and this will be the eighth consecutive month with average solar flux above 180. The average solar flux at 1 AU since May 1, 2024 is 205. There is an increasing chance solar cycle 25 could have a higher 1 year solar flux average than solar cycle 23. The above plot displays a projected peak for the ISN 365d smoothed sunspot number on October 12, 2024. All the other smoothed sunspot numbers as well as the smoothed 365d solar flux have projected peaks October 12-15. A sudden decrease in activity during the first months of 2025 could move the SC25 max to sometime between July and October 2024.

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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.