The geomagnetic field was at quiet to active levels on October 26. Solar wind speed at SOHO ranged between 311 and 550 km/sec. The high latitude magnetometer at Andenes recorded quiet to active levels. The above 10 MeV proton flux was at 58 pfu at the end of the day, slowly increasing, reaching 91 pfu as I write this. The total field of the IMF increased abruptly at 11:34 UT, likely the arrival of the October 23 CME. Another sudden increase was observed at 15:35 UT at ACE, the arrival of the October 24 CME. Since late on Oct.26 the Bz component of the IMF has been predominantly northwards resulting in quiet geomagnetic conditions so far on Oct. 27.
Solar flux density measured at 20h UT on 2.8 GHz was 238.4 - increasing 41.2 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 181.48. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 181.48 on April 27, 2024). The Potsdam WDC planetary A index was 11 (STAR Ap - based on the mean of three hour interval ap indices: 10.6). Three hour interval K indices: 10113344 (planetary), 12113444 (Boulder), 30002344 (Andenes).
The background x-ray flux is at the class C3 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 22 active regions using 2K resolution (SN: 520) and in 20 active regions using 1K resolution (SN: 347) SDO/HMI images.
AR 13863 [S09W36] decayed in parts of the spot
group, however, new flux emerged ahead of the leader spot before noon and
some new spots formed.
AR 13865 [S22W20] decayed slowly and quietly.
AR 13866 [S12W09] developed slightly in the
leading spot section and was
quiet.
AR 13868 [S11E08] decayed slowly and quietly.
AR 13869 [S17E28] was mostly quiet and stable. M flares are possible.
AR 13870 [S19W58] developed slowly and was mostly quiet.
AR 13872 [S17E42] produced 2 major flares where the flare center was
at or close to the magnetic delta configuration in the northeastern part of
the huge trailing penumbra. Further major flaring is possible.
AR 13873 [S11E48] was mostly quiet.
AR 13874 [N23E08] developed further, has polarity intermixing, and
could produce a minor M class flare.
AR 13875 [N26E23] developed slowly and quietly.
AR 13876 [S04E20] developed further and has a simple magnetic layout.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S10261 [N17W19] decayed slowly and slowly.
S10275 [N17W27] decayed slowly and quietly.
S10277 [N04W16] was quiet and stable.
S10278 [S24E52] decayed slowly and quietly.
S10279 [N16E33] reemerged with tiny spots.
S10282 [N16E21] was quiet and stable.
S10284 [S15E57] was quiet and stable.
S10285 [S15E65] was quiet and stable.
New region S10288 [N01E01] was observed with tiny spots in an old
plage area.
New region S10289 [N17E83] rotated into partly into view, is unstable and produced
the majority of the C and M
flares.
New region S10290 [S23E15] was observed with tiny spots in an old
plage area.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C3.1 | 01:01 | 13869 | GOES16 | ||
| C3.2 | 01:25 | 13872 | GOES16 | ||
| C3.0 | 01:50 | 13872 | GOES16 | ||
| C4.5 | 02:19 | S19E54 | 13872 | GOES16 | |
| C3.1 | 02:49 | N17E90 (SDO/AIA) | S10289 | GOES16 | |
| C3.5 | 03:17 | N16E90 (SDO/AIA) | S10289 | GOES16 | |
| C3.9 | 04:05 | 13873 | GOES16 | ||
| C4.0 | 04:09 | 13873 | GOES16 | ||
| C4.9 | 05:34 | N17E90 (SDO/AIA) | S10289 | GOES16 | |
| M9.5 | 06:23 | S14E56 (SDO/AIA) | 13872 | GOES16 | |
| X1.8/3N | 07:16 | 13872 | GOES16 | halo CME, moderate type II and strong type IV radio sweeps | |
| M2.2 | 10:26 | 13869 | GOES16 | ||
| M2.2 | 11:50 | N17E90 (SDO/AIA) | S10289 | GOES16 | |
| M2.8 | 12:05 | N17E90 (SDO/AIA) | S10289 | GOES16 | |
| M1.7 | 12:50 | N17E90 (SDO/AIA) | S10289 | GOES16 | |
| M1.1 | 13:26 | N17E90 (SDO/AIA) | S10289 | GOES16 | |
| M1.6 | 14:16 | N17E90 (SDO/AIA) | S10289 | GOES16 | |
| C7.5 | 17:10 | N17E90 (SDO/AIA) | S10289 | GOES16 | |
| C8.6 | 17:57 | N17E90 (SDO/AIA) | S10289 | GOES16 | |
| C9.3 | 18:14 | 13873 | GOES16 | simultaneous flare in AR 13870 | |
| C9.1 | 18:35 | N17E90 (SDO/AIA) | S10289 | GOES16 | |
| C7.6 | 19:11 | N17E90 (SDO/AIA) | S10289 | GOES16 | |
| C7.5 | 19:27 | 13874 | GOES16 | ||
| C5.6 | 20:27 | 13869 | GOES16 | ||
| C9.7 | 22:38 | N17E90 (SDO/AIA) | S10289 | GOES16 | |
| C5.9 | 23:36 | N17E90 (SDO/AIA) | S10289 | GOES16 |
October 24: An asymmetric full halo CME was observed after the X3
flare in AR 13872. The CME reached ACE at 15:35 UT.
October 25: No obviously Earth directed CMEs were observed.
October 26: A fast and well defined full halo CME was observed after
the closely spaced major flares in AR 13872. The CME could reach Earth
before noon on October 28.
[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 (CH1250) was Earth facing on October 24-25. A positive polarity northern hemipshere coronal hole (CH1251) could rotate across the central meridian on October 30-31.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle and high latitudes is very poor. Propagation on long distance northeast-southwest paths is poor to fair.
The geomagnetic field is expected to be quiet to active on October 27 due to CME effects. On October 28-29 the CME associated with the Oct.26 flares in AR 13872 could cause unsettled to severe storm disturbance levels.
| 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.
(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 | ||||||||||
| 13863 | 2024.10.17 2024.10.19 |
11 | 24 | 8 | S08W37 | 0120 | DAI | DAI |
 |
 |
location: S09W36 |
| 13862 | 2024.10.18 2024.10.19 |
S15W45 |
 |
location: S17W49 | |||||||
| 13865 | 2024.10.19 2024.10.20 |
1 | 4 | S22W16 | 0020 | HSX | AXX |
 |
 |
location: S22W20 area: 0005 |
|
| 13864 | 2024.10.19 2024.10.20 |
N25W37 | location: N25W30 | ||||||||
| 13866 | 2024.10.20 2024.10.21 |
2 | 30 | 8 | S12W08 | 0010 | BXO | BXI |
 |
 |
area: 0050 location: S12W09 |
| S10261 | 2024.10.20 | 8 | 3 | N17W19 | 0015 | AXX |
 |
 |
|||
| 13867 | 2024.10.20 2024.10.21 |
S15W38 | location: S21W33 | ||||||||
| 13868 | 2024.10.21 2024.10.21 |
1 | 9 | 5 | S11E06 | 0150 | HSX | CHO |
 |
 |
location: S11E08 area: 0280 |
| S10265 | 2024.10.21 | S25W17 | |||||||||
| S10266 | 2024.10.21 | N09W17 | |||||||||
| 13869 | 2024.10.22 2024.10.23 |
15 | 42 | 27 | S17E28 | 0410 | EKI | EKC |
 |
 |
beta-gamma area: 0590 |
| 13870 | 2024.10.22 2024.10.24 |
5 | 10 | 5 | S22W66 | 0040 | CAO | DAO |
 |
 |
location: S19W58 area: 0160 SWPC location is way off |
| S10269 | 2024.10.22 | N30W40 | |||||||||
| 13875 | 2024.10.23 2024.10.24 |
6 | 21 | 11 | N29E17 | 0020 | CAO | DRI |
 |
 |
location: N26E23 area: 0030 SWPC location is way off |
| S10272 | 2024.10.23 | N18W05 | |||||||||
| 13872 | 2024.10.23 2024.10.24 |
10 | 37 | 18 | S18E40 | 0280 | DKI | EKC |
 |
 |
beta-gamma-delta area: 0770 location: S17E42 |
| 13871 | 2024.10.24 | S09E19 | part of AR 13869 | ||||||||
| 13873 | 2024.10.24 2024.10.24 |
5 | 36 | 20 | S10E49 | 0120 | DAI | DAI |
 |
 |
beta-gamma location: S11E48 area: 0190 |
| S10275 | 2024.10.24 | 5 | N17W27 | 0006 | BXO |
 |
 |
||||
| S10276 | 2024.10.24 | S25W09 | |||||||||
| S10277 | 2024.10.24 | 3 | 2 | N04W16 | 0008 | AXX |
 |
 |
|||
| S10278 | 2024.10.24 | 4 | 2 | S24E52 | 0008 | BXO |
 |
 |
|||
| S10279 | 2024.10.24 | 4 | 1 | N16E33 | 0008 | BXO |
 |
||||
| 13874 | 2024.10.24 2024.10.25 |
10 | 25 | 16 | N27E06 | 0030 | CAO | DAI |
 |
 |
beta-gamma location: N23E08 area: 0200 |
| S10281 | 2024.10.24 | S21W28 | |||||||||
| S10282 | 2024.10.25 | 2 | 2 | N16E21 | 0008 | BXO |
 |
 |
|||
| 13876 | 2024.10.25 2024.10.25 |
5 | 23 | 13 | S01E20 | 0020 | DAI | DAI |
 |
 |
location: S04E20 area: 0260 SWPC area and location are at odds with reality |
| S10284 | 2024.10.25 | 2 | 1 | S15E57 | 0008 | BXO |
 |
 |
|||
| S10285 | 2024.10.25 | 3 | 1 | S15E65 | 0020 | HRX |
 |
 |
|||
| S10286 | 2024.10.25 | N08W21 |
 |
||||||||
| S10287 | 2024.10.25 | N15E03 |
 |
||||||||
| S10288 | 2024.10.26 | 2 | 1 | S01E01 | 0005 | AXX |
 |
||||
| S10289 | 2024.10.26 | 1 | 1 | N17E83 | 0130 | HAX |
 |
||||
| S10290 | 2024.10.26 | 5 | 2 | S23E15 | 0010 | AXX |
 |
||||
| Total spot count: | 71 | 300 | 147 | ||||||||
| Sunspot number: | 181 | 520 | 347 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 131 | 366 | 213 | (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): | 199 | 286 | 278 | ||||||||
| 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 |
| 2023.01 | 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 |
| 2023.03 | 157.2 | 155.6 | 123.3 | 121.1 (+3.3) | 14.42 |
| 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 | 127.8 (+3.0) | 12.20 |
| 2023.12 | 151.1 | 146.4 | 114.2 | 129.4 (+1.6) | 9.60 |
| 2024.01 | 164.6 | 159.3 | 126.0 | 131.1 (+1.7) | 5.46 |
| 2024.02 | 172.5 | 168.3 | 123.0 | 136.8 (+5.7) | 5.31 |
| 2024.03 | 154.4 | 152.9 | 103.7 | 141.3 (+4.5) | 11.03 |
| 2024.04 | 161.3 | 162.6 | 136.5 | (145.3 projected, +4.0) | 9.69 |
| 2024.05 | 187.7 | 191.9 | 171.7 | (151.6 projected, +6.3) | 23.56 (SC25 peak) |
| 2024.06 | 184.3 | 190.2 | 164.2 | (155.5 projected, +3.9) | 10.24 |
| 2024.07 | 196.6 | 203.0 | 196.5 | (158.4 projected, +2.9) | 7.13 |
| 2024.08 | 246.1 (cycle peak) |
252.2 | 215.5 (SC25 peak) | (160.4 projected, +2.0) | 15.96 |
| 2024.09 | 195.7 | 197.8 | 141.4 | (163.1 projected, +2.7) | 15.36 |
| 2024.10 | 213.3 (1) | 124.2 (2A) / 148.1 (2B) / 205.6 (2C) ISN preliminary average to date: 156 |
(165.4 projected, +2.3) | (20.4) | |
| 2024.11 | (163.7 projected, -1.7) | ||||
| 2024.12 | (160.7 projected, -3.0) | ||||
| 2025.01 | (156.3 projected, -4.4) | ||||
| 2025.02 | (149.6 projected, -6.7) | ||||
| 2025.03 | (144.8 projected, -4.8) | ||||
| 2025.04 | (141.6 projected, -3.2) | ||||
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
Sunspot activity in October 2024 increased over September and looks to be headed for an SSN near 160. The average solar flux for October will become the second highest for a month during SC25. The above plot now displays the peak in 365d smoothed sunspot numbers in mid October. ISN has a peak on October 15, NOAA SN on October 14 while both the 1K and 2K SDO SN peaked on October 16. Assuming that the average sunspot number from October 2024 until April 14, 2025 becomes 150, we would be looking at a 365 days smoothed sunspot maximum of 164.5 centered on October 15. Should the average sunspot number for that period become 160 we would get a peak near 169.7.
--------------------------------------------------------------------------------------
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.
