The geomagnetic field was quiet to unsettled on September 30. Solar wind speed at SOHO ranged between 385 and 527 km/sec. The high latitude magnetometer at Andenes recorded quiet to minor storm levels.
Solar flux density measured at 20h UT on 2.8 GHz was 159.1 - increasing 28.6 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 155.02. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 8.8). Three hour interval K indices: 22322222 (planetary), 11433232 (Boulder), 22124454 (Andenes).
The background x-ray flux is at the class C1 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 18 active regions using 2K resolution (SN: 308) and in 12 active regions using 1K resolution (SN: 175) SDO/HMI images.
Region 13440 [N18W80] developed slightly in the
eastern part as it rotated quietly to the northwest limb.
Region 13445 [S16W80] decayed slowly and was mostly quiet as it
rotated to the southwest limb.
Region 13447 [S22W59] decayed slowly and quietly.
Region 13448 [N13E07] was quiet and stable.
Region 13450 [S19E31] produced a few flares and has M class flare
potential. C1 flares: C1.9 @ 06:29 UT
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S8993 [N15W06] was mostly quiet and stable.
S8994 [S21E06] was quiet and stable.
S8996 [N15W12] decayed slightly and was quiet.
S9002 [N15W75] decayed slowly and was quiet.
S9003 [N16E61] developed into a compact region
with several magnetic delta structures. M class flaring is likely.
Apparently SWPC regards this and AR S9004 as one region.
S9004 [N10E60] developed further becoming a complex, compact region.
M class flaring is likely. By noon a magnetic delta had formed, however,
this disappeared later in day. Some interaction with AR S9003 is possible.
New region S9005 [N22E21] was split off from AR 13448 as more tiny
spots emerged in a relatively small area.
New region S9006 [S18W27] emerged with tiny spots.
New region S9007 [N07W10] emerged with tiny spots.
New region S9008 [S12E78] rotated into view with tiny spots.
New region S9009 [N15W31] emerged with a tiny spot.
New region S9010 [N27W43] emerged with a tiny spot.
New region S9011 [S36W19] was observed with a tiny spot in an old
plage area.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C2.4 | 00:48 | 13445 | GOES16 | ||
| C4.2 | 01:15 | S9003 | GOES16 | simultaneous flare in AR 13448 | |
| C7.2 | 04:09 | S9003 | GOES16 | ||
| C7.1 | 05:38 | 13445 | GOES16 | ||
| C3.9 | 05:50 | S9003 | GOES18 | ||
| C8.0/1F | 06:00 | S15W65 | 13445 | GOES18 | |
| C2.4 | 06:56 | N14E71 | S9003 | GOES16 | |
| C2.6 | 10:46 | N10E69 | S9004 | GOES16 | |
| C9.6 | 11:57 | S18W68 | 13445 | GOES16 | |
| C4.9 | 12:29 | N11E69 | S9004 | GOES16 | |
| C3.9 | 14:18 | 13447 | GOES16 | ||
| C5.1 | 14:44 | 13450 | GOES16 | ||
| C2.8 | 15:33 | S9003 | GOES16 | ||
| C6.3/1N | 16:07 | S9004 | GOES16 | ||
| M1.2 | 16:35 | S9004 | GOES16 | smaller simultaneous flares in AR 13450 and S9003 | |
| C5.2 | 17:09 | S9008 | GOES16 | ||
| C4.7 | 18:25 | N16E62 | S9003 | GOES16 | |
| C2.7 | 20:37 | N15E61 | S9003 | GOES16 | |
| C3.2 | 20:52 | GOES16 | |||
| C5.6 | 21:31 | S9004 | GOES16 | ||
| C6.6 | 21:45 | 13450 | GOES16 | ||
| C2.6 | 23:01 | S9003 | GOES16 | ||
| C2.8 | 23:54 | S9004 | GOES16 |
September 28-30: No obviously Earth directed CMEs were observed.
[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 coronal hole (CH1177) in the northern hemisphere was Earth facing on September 30.
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 likely to be quiet to unsettled on October 1-2 and quiet to active on October 3-4 due to effects from a positive polarity coronal hole.
| 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 | ||||||||||
| 13440 | 2023.09.17 2023.09.18 |
1 | 2 | 1 | N18W85 | 0010 | AXX | HRX |
 |
 |
location: N18W80 |
| 13442 | 2023.09.18 2023.09.20 |
S09W83 |
location: S09W79 |
||||||||
| 13444 | 2023.09.19 2023.09.21 |
N22W83 | location: N23W73 | ||||||||
| 13446 | 2023.09.21 2023.09.22 |
N23W50 |
location: N23W39 |
||||||||
| 13445 | 2023.09.21 2023.09.22 |
1 | 1 | 1 | S14W79 | 0050 | HSX | HSX |
 |
 |
location: S16W80 area: 0100 |
| 13447 | 2023.09.24 2023.09.25 |
3 | 3 | 2 | S22W57 | 0080 | CSO | CAO |
 |
 |
area: 0130 location: S22W59 |
| 13448 | 2023.09.24 2023.09.25 |
1 | 16 | 4 | N13E06 | 0080 | HSX | HSX |
 |
 |
area: 0220 location: N13E07 |
| S8991 | 2023.09.24 | N23W42 | |||||||||
| S8993 | 2023.09.25 | 16 | 7 | N15W06 | 0070 | DRI |
 |
 |
|||
| S8994 | 2023.09.25 | 3 | S21E06 | 0005 | BXO |
 |
 |
||||
| 13449 | 2023.09.26 | 10 | N15W09 | 0110 | CSI | SWPC includes both AR S8993 and S8996 in this region | |||||
| S8995 | 2023.09.26 | N05W53 | |||||||||
| S8996 | 2023.09.26 | 5 | 3 | N15W12 | 0070 | CSO |
 |
 |
|||
| S8997 | 2023.09.26 | S14W16 | |||||||||
| 13450 | 2023.09.27 2023.09.27 |
12 | 32 | 17 | S19E31 | 0170 | EAI | EAI |
 |
 |
beta-gamma area: 0380 |
| S8999 | 2023.09.28 | N23W13 | |||||||||
| S9000 | 2023.09.28 | S17W36 |
 |
||||||||
| S9001 | 2023.09.28 | S28W17 | |||||||||
| S9002 | 2023.09.29 | 1 | N15W75 | 0002 | AXX |
 |
 |
||||
| S9003 | 2023.09.29 | 10 | 6 | N16E61 | 0120 | DAC |
 |
 |
beta-delta | ||
| S9004 | 2023.09.29 | 18 | 6 | N10E60 | 0220 | DAC |
 |
 |
beta-gamma | ||
| 13451 | 2023.09.30 | 8 | N14E60 | 0080 | DAI | SWPC includes both AR S9003 and S9004 in this region | |||||
| S9005 | 2023.09.30 | 9 | 6 | N22E21 | 0030 | BXO |
 |
||||
| S9006 | 2023.09.30 | 3 | 1 | S18W27 | 0010 | BXO |
 |
||||
| S9007 | 2023.09.30 | 2 | 1 | N07W10 | 0006 | AXX |
 |
||||
| S9008 | 2023.09.30 | 4 | S12E79 | 0015 | BXO |
 |
|||||
| S9009 | 2023.09.30 | 1 | N15W31 | 0001 | AXX |
 |
|||||
| S9010 | 2023.09.30 | 1 | N27W43 | 0001 | AXX |
 |
|||||
| S9011 | 2023.09.30 | 1 | S36W19 | 0002 | AXX |
 |
|||||
| Total spot count: | 36 | 128 | 55 | ||||||||
| Sunspot number: | 106 | 308 | 175 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 66 | 169 | 96 | (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): | 117 | 169 | 140 | ||||||||
| 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 |
| 2022.02 | 109.1 | 106.5 | 60.9 | 64.7 (+4.6) | 10.46 |
| 2022.03 | 117.0 | 115.8 | 78.6 | 68.7 (+4.0) | 10.20 |
| 2022.04 | 130.8 | 131.7 | 84.0 | 73.0 (+4.3) | 11.79 |
| 2022.05 | 133.8 | 136.8 | 96.5 | 77.4 (+4.4) | 7.48 |
| 2022.06 | 116.1 | 119.8 | 70.3 | 81.1 (+3.7) | 8.20 |
| 2022.07 | 125.4 | 129.5 | 91.4 | 86.7 (+5.6) | 9.51 |
| 2022.08 | 114.2 | 117.1 | 74.6 | 92.6 (+5.9) | 10.92 |
| 2022.09 | 135.1 | 136.5 | 96.0 | 96.5 (+3.9) | 12.18 |
| 2022.10 | 133.5 | 132.7 | 95.5 | 98.9 (+2.4) | 11.16 |
| 2022.11 | 123.4 | 120.7 | 80.5 | 101.1 (+2.2) | 9.33 |
| 2022.12 | 147.9 | 143.4 | 112.8 | 106.7 (+5.6) | 10.99 |
| 2023.01 | 182.4 | 176.6 | 144.4 | 113.4 (+6.7) | 8.73 |
| 2023.02 | 167.2 | 163.2 | 111.3 | 117.9 (+3.5) | 14.48 (current SC25 peak) |
| 2023.03 | 157.2 | 155.6 | 123.3 | 121.2 (+3.3) | 14.42 |
| 2023.04 | 145.4 | 146.4 | 96.4 | (126.6 projected, +5.4) | 13.40 |
| 2023.05 | 155.6 | 159.2 | 137.9 | (132.2 projected, +5.6) | 10.67 |
| 2023.06 | 161.7 | 166.8 | 163.4 | (135.4 projected, +3.2) | 8.95 |
| 2023.07 | 176.4 | 182.2 | 159.1 | (135.8 projected, +0.4) | 8.15 |
| 2023.08 | 153.7 | 157.6 | 114.9 | (137.6 projected, +1.8) | 7.19 |
| 2023.09 | 154.4 | 156.0 | 133.6 | (141.0 projected, +3.4) | (14.4) |
| 2023.10 | (1) | (2A/2B) / 142.1 (2C) | (142.8 projected, +1.8) | ||
| 2023.11 | (145.4 projected max SC25, +2.6) | ||||
| 2023.12 | (144.5 projected, -0.9) | ||||
| 2024.01 | (141.7 projected, -2.8) | ||||
| 2024.02 | (141.5 projected, -0.2) | ||||
| 2024.03 | (141.0 projected, -0.5) | ||||
| 2024.04 | (138.2 projected, -2.8) | ||||
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
Looking back 6 months, the 365d smoothed values for solar flux and all sunspot numbers with the exception of NOAA's, are all above their solar cycle 24 peak. The first peak of solar cycle 25 is forecast to be between July 7 and 10, 2023 (solar flux on July 7, ISN and STAR 1K and 2K all have that peak on July 9, while NOAA peaks on July 10). This is unlikely to be the final peak of SC25, however, there is a small probability that it is the actual sunspot and solar flux maximum.
--------------------------------------------------------------------------------------
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.
