Solar Terrestrial Activity Report

Activity chart

Last major update issued on February 16, 2025 at 09:30 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 (February 7, 2025)
Solar cycle Solar cycles 23-25 (February 1, 2025) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (February 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 (February 1, 2025) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (February 1, 2025) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (January 11, 2025) 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 unsettled to minor storm levels on February 15 under the influence of effects associated with CH1270. Solar wind speed at SOHO ranged between 504 and 704 km/sec, averaging 589 km/sec (+92 km/sec compared to the previous day). The high latitude magnetometer at Andenes recorded unsettled to major storm levels. The above 10 MeV proton flux was at background levels all day.

Solar flux density measured at 20h UT on 2.8 GHz was 184.0 - decreasing 51.6 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 192.96. In comparison SC24 peaked on June 28, 2014 at 145.50 while SC23 peaked on February 23, 2002 at 198.15. Current SC25 peak: 193.35 on August 7, 2024 (subtracting a baseline solar flux level of 65, this is +59.44% compared to the SC24 peak and -3.61% compared to the SC23 peak). The Potsdam WDC planetary A index was 24 (STAR Ap - based on the mean of three hour interval ap indices: 24.0). Three hour interval K indices: 45334334 (planetary), 44344333 (Boulder), 45334456 (Andenes).

The background x-ray flux is at the class C1 level (GOES 18).

At the time of counting spots (see image time), spots were observed in 21 active regions using 2K resolution (SN: 443) and in 20 active regions using 1K resolution (SN: 326) SDO/HMI images.

AR 13986 [N06W62] was quiet and stable.
AR 13989 [N18W12] was quiet and stable.
AR 13990 [S09E02] simplified and lost the magnetic delta configuration. There's still some polarity intermixing and further M class flaring is possible. C1 flares: C1.5 @ 05:43, C1.8 @ 13:20, C1.8 @ 23:30 UT
AR 13991 [S12E21] developed slowly and quietly.
AR 13992 [S06W52] decayed slowly and was mostly quiet.
AR 13993 [N16E49] was mostly quiet and stable.
AR 13994 [S18W18] was mostly quiet and stable. C1 flares: C1.6 @ 02:13 UT
AR 13995 [S22W46] decayed slowly and quietly.
New AR 13996 [S16E66] rotated into view on February 14 and was numbered the next day by SWPC. The spot group produced several C flares. C1 flares: C1.9 @ 01:19, C1.4 @ 01:44, C1.4 @ 03:24, C1.5 @ 03:28, C1.2 @ 03:58, C1.3 @ 04:19, C1.6 @ 12:21, C1.9 @ 13:33, C1.4 @ 18:29 UT
New AR 13997 [N02E43] emerged on February 13 and received its NOAA number 2 days later as development persisted.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S10791 [S19E08] was quiet and stable.
S10795 [N18E13] was quiet and stable.
S10796 [N12E18] was mostly quiet and stable. C1 flares: C1.9 @ 01:04 UT
S10797 [N10W53] was quiet and stable.
S10799 [S03W33] was quiet and stable.
S10801 [S30W22] was quiet and stable.
New region S10802 [N12E27] was observed with tiny spots in an old plage area.
New region S10803 [S14E80] rotated into view with a few spots. C1 flares: C1.5 @ 09:29 UT
New region S10804 [N06E65] emerged after noon with tiny spots.
New region S10805 [S08E48] was observed with tiny spots in an old plage area.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.3 00:31   13997 GOES16  
C3.1 00:39   13996 GOES16  
C2.8 07:23   13996 GOES16  
C2.4 13:58   13996 GOES16  
C2.2 14:06   13996 GOES16  
C3.6 19:36 behind northwest limb 13983 GOES16  
C2.0 20:15   13997 GOES16  
C2.0 21:03   13992 GOES16  
C2.8 22:16   13997 GOES16  
C2.6 22:28   S10803 GOES16  
C2.0 23:00   13992 GOES16  
C3.9 00:05   S10803 GOES16 incorrectly assigned to AR 13996 by SWPC

Coronal mass ejections (CMEs)

February 13-15: 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]

A recurrent negative polarity southern hemisphere coronal hole (CH1270) was in an Earth facing position on February 9-14.

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 fair.

Forecast

The geomagnetic field is expected to be at quiet to active levels on February 15-17 due to effects from CH1270.

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
13986 2025.02.04
2025.02.05
1 1 1 N06W62 0080 HSX HAX     was AR S10772

area: 0180

13987 2025.02.05
2025.02.06
      S07W61           was AR S10774

location: S09W51

13989 2025.02.08
2025.02.09
1 8 2 N18W14 0270 HHX CHO     was AR S10780

location: N18W12

13990 2025.02.09
2025.02.10
18 69 38 S09W00 0310 CKI DKI     beta-gamma

was AR S10783

area: 0390

location: S09E02

13992 2025.02.10
2025.02.12
7 21 9 S05W54 0060 EAO EAO    

was AR S10785

location: S06W52

area: 0180

13991 2025.02.10
2025.02.11
2 25 9 S13E17 0010 AXX CRI     was AR S10787

area: 0050

location: S12E21

S10789 2025.02.10   3 1 S05W04 0005   AXX      
13994 2025.02.11
2025.02.13
6 21 16 S19W18 0030 CRO CAI     was AR S10790

area: 0100

location: S18W18

S10791 2025.02.12   11 3 S19E08 0020   BXO      
13993 2025.02.13
2025.02.13
2 7 4 N16E47 0220 HSX CKO     location: N16E63

area: 0340

location: N16E49

13995 2025.02.13
2025.02.14
2 5 4 S22W44 0020 CSO CRO     was AR S10792

location: S22W46

area: 0060

S10793 2025.02.13       N10W04            
13997 2025.02.13
2025.02.15
5 23 13 N03E42 0030 CAO DAI     beta-gamma

was AR S10794

location: N02E43

area: 0140

S10795 2025.02.13   8 4 N18E13 0020   BXO      
S10796 2025.02.13   3 1 N12E18 0005   BXO      
S10797 2025.02.14   2 1 N10W53 0005   BXO      
13996 2025.02.14
2025.02.15
9 24 13 S11E65 0090 ESO EAI     beta-gamma

was AR S10798

location: S16E66

area: 0360

S10799 2025.02.14   3 1 S03W33 0006   BXO      
S10800 2025.02.14       S14E40            
S10801 2025.02.14   2   S30W22 0002   AXX      
S10802 2025.02.15   7 1 N12E27 0010   BXO      
S10803 2025.02.15   4 3 S14E80 0020   CRO      
S10804 2025.02.15   3 1 N06E65 0005   BXO      
S10805 2025.02.15   2 1 S08E48 0004   AXX      
Total spot count: 53 252 126  
Sunspot number: 153 462 326  (total spot count + 10 * number of spotted regions)
Weighted SN: 106 316 190  (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): 168 254 261  

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
2023.06 161.7 166.8 160.5 125.3 (+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
2024.01 164.6 159.3 126.0 131.2 (+1.7) 5.46
2024.02 172.5 168.3 123.0 136.9 (+5.7) 5.31
2024.03 154.4 152.9 103.7 141.4 (+4.5) 11.03
2024.04 161.3 162.6 137.0 144.5 (+3.1) 9.69
2024.05 187.7 191.9 172.1 149.1 (+4.6) 23.56
(SC25 peak)
2024.06 184.3 190.2 164.1 152.7 (+3.6) 10.24
2024.07 196.6 203.0 196.8 154.9 (+2.3) 7.13
2024.08  246.1
(cycle peak)
252.2 216.0  (SC25 peak) (156.2 projected, +1.3) 15.96
2024.09 195.7 197.8 141.1 (158.3 projected, +2.1) 15.36
2024.10 221.0 219.6 166.3 (159.1 projected, +0.8) 18.99
2024.11 199.6 195.3 152.5 (156.5 projected, -2.6) 9.33
2024.12 197.3 191.2 154.5 (152.1 projected, -4.4) 8.42
2025.01 190.3 184.2  137.0 (145.8 projected, -6.3) 13.17
2025.02  182.7 (1)   75.9 (2A) / 141.6 (2B) / 171.6 (2C) (137.2 projected, -8.6) (14.6)
2025.03       (130.8 projected, -6.4)  
2025.04       (126.2 projected, -4.6)  
2025.05       (120.9 projected, -5.3)  
2025.06       (115.6 projected, -5.3)  
2025.07       (110.9 projected, -4.7)  

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 27 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 February 10, 2025

Sunspot activity has been on a slowly decreasing trend since September 2024 (using the mean solar flux over 3 solar rotations as a proxy). The 365 days average ISN has a peak on July 8, 2024, but is still expected to peak in October 2024 due to low sunspot numbers in March and the first half of April 2024. Unless there is an uptick in sunspot activity over the next couple of months, the 365 days average solar flux is likely to peak 1-2% below the peak of solar cycle 23. While the 365d average solar flux peaks of SC23 and SC25 are similar, sunspot numbers will peak significantly lower for SC25 compared to SC23.

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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.