The geomagnetic field was at very quiet levels on October 25. Solar wind speed at SOHO ranged between 315 and 353 km/sec. The high latitude magnetometer at Andenes recorded quiet to unsettled levels. The above 10 MeV proton flux was at 0.8 pfu at the end of the day, slowly increasing.
Solar flux density measured at 20h UT on 2.8 GHz was 209.3 - increasing 14.8 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 181.18. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 181.18 on April 26, 2024). The Potsdam WDC planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 1.5). Three hour interval K indices: 10000001 (planetary), 10101211 (Boulder), 30000013 (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 22 active regions using 2K resolution (SN: 468) and in 19 active regions using 1K resolution (SN: 317) SDO/HMI images.
AR 13857 [S08W76] developed slowly early in the day, then decayed
again.
AR 13862 [S17W36] decayed slowly and quietly.
AR 13863 [S08W22] decayed slowly and quietly.
AR 13865 [S21W05] decayed slowly and quietly.
AR 13866 [S12E02] decayed slowly and was mostly quiet.
AR 13868 [S10E21] decayed slowly and quietly.
AR 13869 [S16E42] produced several C flares. A major flare is possible.
AR 13870 [S19W44] became spotless early in the day, then new flux
emerged, several spots formed, and C flares were recorded.
AR 13872 [S17E55] is the most complex spot group on the disk and
continues to produce major flares. On October 26 an M9.5 flare was recorded
at 06:23 (SDO/AIA location: S14E56), then an X1.86 flare was recorded at
07:06 UT. An impressive CME was observed in LASCO imagery.
AR 13873 [S11E62] produced the only M flare of the day as well as
several C flares.
New AR 13874 [N24E21] emerged on October 24 and was numbered the next
day by SWPC.
New AR 13875 [N27E35] emerged on October 23 with SWPC numbering the
region 2 days later.
New AR 13876 [S04E34] emerged early in the day and quickly developed
spots. C flares are possible.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S10261 [N17W07] was quiet and stable.
S10275 [N18W03] decayed slowly and quietly.
S10277 [N04W02] was quiet and stable.
S10278 [S23E65] decayed slowly and quietly.
New region S10282 [N17E35] emerged with tiny spots.
New region S10284 [S15E70] rotated into view with a small spot.
New region S10285 [S14E79] rotated into view with a small spot.
New region S10286 [N08W08] emerged with tiny spots.
New region S10287 [N15E16] emerged with a tiny spot.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C3.7 | 00:50 | southwest limb | GOES16 | ||
| C2.5 | 02:02 | 13873 | GOES16 | ||
| C2.6 | 03:02 | 13872 | GOES16 | ||
| C3.5 | 05:18 | 13869 | GOES16 | ||
| C2.4 | 06:16 | 13873 | GOES16 | ||
| C2.8 | 06:59 | S08E35 (SDO/AIA) | 13869 | GOES16 | simultaneous flare at S08W90 |
| M1.1 | 07:33 | S10E75 | 13873 | GOES16 | |
| C3.5 | 10:35 | southwest limb | GOES16 | ||
| C2.8 | 11:06 | southwest limb | GOES16 | simultaneous flares in ARs 13869 and 13872 | |
| C2.6 | 11:21 | 13873 | GOES16 | ||
| C2.9 | 11:49 | 13872 | GOES16 | ||
| C2.0 | 12:45 | 13873 | GOES16 | ||
| C2.2 | 14:14 | 13869 | GOES16 | ||
| C2.4 | 16:41 | 13873 | GOES16 | ||
| C2.7 | 17:27 | 13873 | GOES16 | ||
| C2.8 | 17:56 | 13873 | GOES16 | ||
| C3.2 | 18:58 | S15E41 | 13869 | GOES16 | |
| C2.6 | 19:42 | 13870 | GOES16 | ||
| C3.1 | 20:27 | 13874 | GOES16 | ||
| C3.2 | 22:05 | 13869 | GOES16 | ||
| C3.3 | 22:28 | 13873 | GOES16 | ||
| C3.5 | 23:43 | 13870 | GOES16 |
October 23: A CME was observed after the C7 flare in AR 13863 peaking
at 12:12 UT. The CME could reach Earth on October 26.
October 24: An asymmetric full halo CME was observed after the X3
flare in AR 13872. A solar wind shock could reach Earth on October 26.
October 25: No obviously Earth directed CMEs were observed.
October 26: A fast and well defined full halo CME was observed after
the events in AR 13872. The CME could reach Earth early 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.
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 very poor. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet initially on October 26, after noon components of the October 23 and 24 CMEs could reach Earth and cause unsettled to major storm conditions. Quiet to minor storm is likely on October 27. On October 28 a CME associated with the Oct.26 flares in AR 13872 could cause active to very severe 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.
(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 | ||||||||||
| 13857 | 2024.10.13 2024.10.14 |
2 | S05W88 | 0002 | AXX |
 |
 |
location: S08W76 |
|||
| 13863 | 2024.10.17 2024.10.19 |
4 | 21 | 10 | S08W23 | 0090 | CSO | CAO |
 |
 |
area: 0120 location: S08W22 |
| 13862 | 2024.10.18 2024.10.19 |
4 | S15W31 | 0005 | AXX |
 |
 |
location: S17W36 | |||
| 13865 | 2024.10.19 2024.10.20 |
1 | 5 | 4 | S22W02 | 0020 | HRX | CRO |
 |
 |
location: S21W05 |
| 13864 | 2024.10.19 2024.10.20 |
N25W22 | location: N25W17 | ||||||||
| 13866 | 2024.10.20 2024.10.21 |
3 | 27 | 13 | S12E06 | 0010 | BXO | BXI |
 |
 |
area: 0040 location: S12E02 |
| S10260 | 2024.10.20 | S19W55 | |||||||||
| S10261 | 2024.10.20 | 11 | 5 | N17W07 | 0020 | BXO |
 |
 |
|||
| 13867 | 2024.10.20 2024.10.21 |
S15W24 | location: S21W20 | ||||||||
| 13868 | 2024.10.21 2024.10.21 |
1 | 5 | 2 | S11E20 | 0150 | HSX | CHO |
 |
 |
location: S11E34 area: 0280 |
| S10265 | 2024.10.21 | S25W04 | |||||||||
| S10266 | 2024.10.21 | N09W04 | |||||||||
| 13869 | 2024.10.22 2024.10.23 |
8 | 50 | 27 | S17E43 | 0410 | DKI | FKI |
 |
 |
beta-gamma location: S16E42 area: 0710 |
| 13870 | 2024.10.22 2024.10.24 |
7 | 4 | S22W52 | 0030 | CRO |
 |
 |
location: S19W44 SWPC location is way off |
||
| S10269 | 2024.10.22 | N30W27 | |||||||||
| 13875 | 2024.10.23 2024.10.24 |
3 | 14 | 6 | N29E31 | 0010 | BXO | CRI |
 |
 |
location: N27E35 area: 0030 |
| S10272 | 2024.10.23 | N18E08 |
 |
||||||||
| 13872 | 2024.10.23 2024.10.24 |
10 | 25 | 15 | 0120 | DAI | EKC |
 |
 |
beta-gamma-delta area: 0850 location: S17E55 SWPC position is way off |
|
| 13871 | 2024.10.24 | 1 | S09E33 | 0010 | AXX | part of AR 13869 | |||||
| 13873 | 2024.10.24 2024.10.24 |
5 | 23 | 13 | S10E63 | 0120 | DAI | DKI |
 |
 |
beta-gamma location: S11E62 |
| S10275 | 2024.10.24 | 3 | 1 | N18W13 | 0005 | AXX |
 |
 |
|||
| S10276 | 2024.10.24 | S25E04 |
 |
||||||||
| S10277 | 2024.10.24 | 3 | 2 | N04W02 | 0010 | AXX |
 |
 |
|||
| S10278 | 2024.10.24 | 2 | 1 | S23E65 | 0010 | AXX |
 |
 |
|||
| S10279 | 2024.10.24 | N12E49 |
 |
||||||||
| 13874 | 2024.10.24 2024.10.25 |
6 | 16 | 8 | N27E20 | 0020 | CRO | DAI |
 |
 |
location: N24E21 |
| S10281 | 2024.10.24 | S21W15 |
 |
||||||||
| S10282 | 2024.10.25 | 5 | 1 | N17E35 | 0012 | CRO |
 |
||||
| 13876 | 2024.10.25 2024.10.25 |
5 | 20 | 12 | S01E35 | 0020 | CRO | DRI |
 |
location: S04E34 area: 0060 was AR S10283 |
|
| S10284 | 2024.10.25 | 1 | 1 | S15E70 | 0015 | HRX |
 |
||||
| S10285 | 2024.10.25 | 1 | 1 | S14E79 | 0020 | HRX |
 |
||||
| S10286 | 2024.10.25 | 2 | 1 | N08W08 | 0004 | BXO |
 |
||||
| S10287 | 2024.10.25 | 1 | N15E16 | 0001 | AXX |
 |
|||||
| Total spot count: | 47 | 248 | 127 | ||||||||
| Sunspot number: | 157 | 468 | 317 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 91 | 319 | 198 | (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): | 173 | 257 | 254 | ||||||||
| 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 | 212.3 (1) | 118.4 (2A) / 146.8 (2B) / 201.0 (2C) ISN preliminary average: 153 |
(165.4 projected, +2.3) | (20.7) | |
| 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
September 2024 saw a significant decrease in sunspot numbers compared to the previous month, however, activity was still fairly high. The average solar flux for the month ranks as number 3 of all months during SC25. Taking into account that we started seeing high sunspot numbers April 14, 2024, the most likely candidate for solar maximum would be at or just after October 14, 2024. Assuming that the average sunspot number from now until April 14, 2025 becomes 150, we would be looking at a 365 days smoothed sunspot maximum of 164.5 centered on October 14. 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.
