The geomagnetic field was at quiet levels on October 1. Solar wind speed at SOHO ranged between 407 and 494 km/sec. The high latitude magnetometer at Andenes recorded quiet to unsettled 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 244.6 - decreasing 1.1 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 176.73. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 176.73 on April 2, 2024). The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 5.4). Three hour interval K indices: 22111211 (planetary), 12112323 (Boulder), 23101220 (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 20 active regions using 2K resolution (SN: 523) and in 17 active regions using 1K resolution (SN: 333) SDO/HMI images.
AR
13834 [S18W78] decayed slowly and could become spotless before
rotating out of view.
AR 13835 [S22W54] decayed significantly losing spots and area.
AR 13836 [S11W33] decayed further and was quiet.
AR 13839 [S14E07] has many tiny spots and no significant magnetic
complexity, however, the region produced several flares.
AR 13841 [N12E07] developed and a significant magnetic delta
configuration formed in the trailing spot section. M class flaring is
likely.
AR 13842 [S16E19] developed gaining area, spots. There are multiple
significant magnetic delta structures and another X class flare is possible.
AR 13843 [S09W14] appears to be maturing and lost the magnetic delta
configuration.
AR 13844 [S16W03] developed further and has a magnetic delta
configuration in the intermediate spot section. M class flaring is possible.
New AR 13845 [N18W44] emerged on September 23 and was numbered by
SWPC on Oct. 1 after new flux emerged on Sept.30.
New AR 13846 [S09W61] emerged on September 30 and received its NOAA
number the following day.
New AR 13847 [S28E59] rotated into view on September 30 with SWPC
numbering the spot group the next day.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S10160 [S03W39] decayed slowly and quietly.
S10169 [S19W13] was quiet and stable.
S10171 [S05E14] was quiet and stable.
S10177 [N16W10] was quiet and stable.
S10182 [S07E41] was quiet and stable.
New region S10185 [N13E81] rotated into view with large and huge
spots with a total area larger than that of AR 13842. A major flare is possible.
New region S10186 [N19E28] was observed with tiny spots in an
old plage area.
New region S10187 [N35W04] emerged with a tiny spot.
New region S10188 [S34E18] emerged with tiny spot.
Minor update posted at 10:25 UT on October 2: More LASCO imagery has become available and the X7 flare late on October 1 was associated with a faint full halo CME. The CME could reach Earth sometime between late on October 3 and noon on October 4.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C6.9 | 01:34 | 13841 | GOES16 | ||
| C4.8 | 02:20 | S10185 | GOES16 | ||
| C4.8 | 02:43 | 13842 | GOES16 | ||
| C4.4 | 03:10 | 13842 | GOES16 | ||
| C3.6 | 03:45 | 13842 | GOES16 | ||
| C3.9 | 04:24 | 13843 | GOES18 | ||
| C6.7 | 04:32 | S15E33 | 13842 | GOES18 | |
| C4.9 | 04:39 | S10185 | GOES18 | ||
| C3.5 | 04:57 | 13842 | GOES18 | ||
| C3.2 | 06:14 | 13842 | GOES18 | simultaneous flare in AR 13843 | |
| C3.5 | 06:40 | 13843 | GOES18 | ||
| C3.9 | 07:00 | S13W05 | 13843 | GOES16 | |
| C4.3 | 07:07 | N14E18 | 13841 | GOES16 | |
| C4.3 | 07:12 | N13E90 | S10185 | GOES16 | |
| C5.2 | 07:18 | 13839 | GOES16 | ||
| C3.4 | 07:36 | S10185 | GOES16 | ||
| C3.6 | 09:02 | S10185 | GOES16 | simultaneous flare in AR 13842 | |
| C3.0 | 09:49 | 13842 | GOES16 | ||
| C3.2 | 10:10 | 13842 | GOES16 | ||
| C3.0 | 10:54 | S10185 | GOES16 | simultaneous flare in AR 13842 | |
| C3.5 | 11:35 | S10185 | GOES16 | ||
| C3.3 | 11:52 | S10185 | GOES16 | ||
| C3.2 | 12:36 | S10185 | GOES16 | ||
| C3.4 | 13:13 | 13846 | GOES16 | ||
| C4.6 | 13:27 | 13844 | GOES16 | ||
| C4.9 | 13:29 | 13842 | GOES16 | ||
| C3.7 | 14:31 | S10185 | GOES16 | ||
| M1.0/1N | 14:52 | S12W09 | 13843 | GOES16 | |
| C8.4 | 15:17 | 13842 | GOES16 | LDE | |
| C4.4 | 16:24 | 13842 | GOES16 | ||
| C4.5 | 16:59 | 13843 | GOES16 | ||
| C8.1 | 17:53 | S08W09 | 13843 | GOES16 | |
| M1.5 | 19:17 | 13842 | GOES16 | a smaller flare was observed in AR 13839 at approx. 19:04 | |
| C5.7 | 20:10 | 13844 | GOES16 | ||
| C5.5 | 20:14 | S10185 | GOES16 | ||
| C8.7 | 21:31 | 13842 | GOES16 | ||
| C8.3 | 21:40 | S10185 | GOES16 | simultaneous flare in AR 13841 | |
| X7.1 | 22:20 | S18E16 | 13842 | GOES16 | CME, strong type II radio sweep |
September 29-30: No obviously Earth directed CMEs observed.
October 1: Only a few initial images after the X7 flare are available
at the time I write this. LASCO C2 images do show a CME off the southeast
limb. More imagery is required to determine if any CME components are Earth
directed.
[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 positive polarity trans equatorial coronal hole (CH1245) will likely rotate into an Earth facing position on October 4-5.
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.
The geomagnetic field is expected to be at quiet levels on October 1-3.
| 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 | ||||||||||
| 13834 | 2024.09.19 2024.09.20 |
1 | 1 | 1 | S17W77 | 0010 | AXX | AXX |
 |
 |
location: S18W78 area: 0005 |
| 13835 | 2024.09.22 2024.09.22 |
8 | 5 | 3 | S23W56 | 0030 | CRO | CRO |
 |
 |
location: S22W54 area: 0020 |
| 13836 | 2024.09.22 2024.09.23 |
8 | 26 | 9 | S12W35 | 0070 | CAI | CRO |
 |
 |
area: 0060 location: S11W33 |
| 13845 | 2024.09.23 2024.10.01 |
5 | 11 | 7 | N19W46 | 0030 | CRO | DRO |
 |
 |
location: N18W44 |
| S10156 | 2024.09.24 | S08W48 | |||||||||
| 13838 | 2024.09.24 2024.09.26 |
N15W26 |
 |
location: N16W25 | |||||||
| S10160 | 2024.09.25 | 6 | 2 | S03W39 | 0010 | BXO |
 |
 |
|||
| 13840 | 2024.09.25 2024.09.27 |
N14W42 |
 |
location: N12W41 | |||||||
| 13841 | 2024.09.25 2024.09.28 |
16 | 53 | 30 | N13E04 | 0120 | DAI | DAC |
 |
 |
beta-gamma-delta location: N12E07 area: 0310 |
| 13839 | 2024.09.26 2024.09.26 |
1 | 27 | 7 | S14E06 | 0060 | HSX | CSO |
 |
 |
area: 0140 location: S14E07 |
| S10165 | 2024.09.26 | S38W37 | |||||||||
| S10166 | 2024.09.26 | S26W47 | |||||||||
| 13842 | 2024.09.27 2024.09.28 |
24 | 79 | 44 | S15E18 | 0300 | EKC | EKC |
 |
 |
beta-gamma-delta location: S16E19 area: 0770 |
| S10169 | 2024.09.27 | 7 | 2 | S19W13 | 0015 | AXX |
 |
 |
|||
| S10170 | 2024.09.27 | N25W17 | |||||||||
| S10171 | 2024.09.27 | 11 | 4 | S05E14 | 0030 | BXO |
 |
 |
|||
| S10172 | 2024.09.27 | S03W18 |
 |
||||||||
| 13843 | 2024.09.28 2024.09.29 |
12 | 39 | 22 | S08W11 | 0110 | DAI | DAI |
 |
 |
beta-gamma location: S09W14 area: 0220 |
| S10176 | 2024.09.28 | N17E40 | |||||||||
| S10177 | 2024.09.28 | 2 | 2 | N16W10 | 0005 | AXX |
 |
 |
|||
| S10178 | 2024.09.28 | S14E35 |
 |
||||||||
| 13844 | 2024.09.29 2024.09.30 |
6 | 36 | 19 | S15W02 | 0070 | DSO | DAC |
 |
 |
beta-gamma-delta location: S16W03 area: 0230 |
| S10180 | 2024.09.29 | N01E19 | |||||||||
| 13846 | 2024.09.30 2024.10.01 |
4 | 6 | 5 | S09W57 | 0010 | BXO | DRI |
 |
 |
location: S09W61 area: 0050 |
| S10182 | 2024.09.30 | 2 | 1 | S07E41 | 0005 | BXO |
 |
 |
|||
| 13847 | 2024.09.30 2024.10.01 |
1 | 1 | 1 | S28E59 | 0030 | HRX | HAX |
 |
 |
area: 0050 |
| S10184 | 2024.09.30 | N28E05 |
 |
||||||||
| S10185 | 2024.10.01 | 5 | 4 | N13E81 | 1300 | EKO |
 |
||||
| S10186 | 2024.10.01 | 4 | N19E28 | 0007 | BXO |
 |
|||||
| S10187 | 2024.10.01 | 1 | N34W04 | 0001 | AXX |
 |
|||||
| S10188 | 2024.10.01 | 1 | S34E18 | 0002 | AXX |
 |
|||||
| Total spot count: | 86 | 323 | 163 | ||||||||
| Sunspot number: | 196 | 523 | 333 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 130 | 380 | 220 | (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): | 216 | 288 | 266 | ||||||||
| 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) | 15.3 |
| 2024.10 | 244.6 (1) | 6.3 (2A) / 196 (2B) / 194.7 (2C) | (165.4 projected, +2.3) | (5.4) | |
| 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 counts in August 2024 were much higher than during any previous solar cycle 25 month. In comparison only 3 months during solar cycle 23 had higher SSN. Sunspot counts in early September are still high, although lower than in the beginning of August. With at least 5 consecutive months of high sunspot counts the projected peak for the smoothed ISN (365 days smoothing) has increased significantly to above 160 and could easily surpass 170 if the current activity lasts through October. The month of the peak is likely to occur sometime between July and November 2024.
--------------------------------------------------------------------------------------
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.
