The geomagnetic field was at quiet levels on September 5. Solar wind speed at SOHO ranged between 367 and 400 km/sec. The high latitude magnetometer at Andenes recorded quiet to unsettled levels. The above 10 MeV proton flux was at 1.6 pfu at the end of the day.
Solar flux density measured at 20h UT on 2.8 GHz was 240.7 - decreasing 64.8 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 174.52. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 174.52 on March 7, 2024). The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.0). Three hour interval K indices: 12111112 (planetary), 12123422 (Boulder), 31121112 (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 16 active regions using 2K resolution (SN: 408) and in 13 active regions using 1K resolution (SN: 247) SDO/HMI images.
AR 13804 [S27W69] reemerged with a tiny spot.
AR 13806 [S11W38] decayed losing spots, area
and some complexity. There is still one minor magnetic delta configuration
left and an M flare is possible.
AR 13807 [S18W79] rotated partly out of view. The region was unstable
and produced many C and M flares.
AR 13808 [S10W28] was mostly quiet and stable. The leading penumbra
is close to merging with the trailing spots of AR 13807.
AR 13811 [S10E07] gained spots and could produce M flares.
AR 13813 [S21E23] decayed slowly and was mostly quiet. SWPC is
including AR S10087 in this spot group, and this doesn't make any sense. The
total longitudinal extension of such a spot group would be 31-33 degrees.
AR 13814 [N15E65] was quiet and stable.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S10066 [N23W52] was quiet and stable as minor new flux emerged.
S10076 [S10W05] developed slowly and quietly.
S10084 [N15E05] was quiet and stable.
S10086 [N08E10] was quiet and stable. The northeastern part was split
off into AR S10095.
S10087 [S27E38] was mostly quiet and stable.
New region S10094 [S10E35] emerged with tiny spots.
New region S10095 [N22E18] was observed with tiny spots in an old
plage area.
New region S10096 [N15E48] was observed with tiny spots in an old plage area.
New region S10097 [S12E66] was observed with tiny spots in an
old plage area.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C8.0 | 00:11 | S10087 | GOES16 | ||
| M1.0 | 00:20 | S15W70 | 13807 | GOES16 | |
| C4.7 | 00:43 | S10097 | GOES16 | ||
| C4.5 | 01:17 | 13814 | GOES16 | ||
| C4.4 | 01:38 | 13814 | GOES16 | ||
| C9.2 | 02:08 | S16W72 | 13807 | GOES16 | |
| C4.2 | 02:45 | 13813 | GOES16 | ||
| C3.8 | 03:09 | 13807 | GOES16 | ||
| M1.1 | 03:25 | 13806 | GOES16 | ||
| M1.1 | 03:44 | 13813 | GOES16 | ||
| C5.8 | 04:30 | 13807 | GOES18 | ||
| C6.3 | 04:51 | 13807 | GOES18 | ||
| C6.2 | 05:39 | 13814 | GOES16 | ||
| C6.3 | 05:50 | 13811 | GOES16 | ||
| C6.6 | 07:55 | S22E37 | 13813 | GOES16 | |
| C5.0 | 08:10 | 13807 | GOES16 | ||
| C7.6 | 08:21 | S16W72 | 13807 | GOES16 | |
| M2.8 | 08:56 | S16W72 | 13807 | GOES16 | multiple flare centers |
| M1.3 | 09:04 | 13807 | GOES16 | ||
| M1.6 | 09:42 | 13807 | GOES16 | ||
| C4.3 | 11:40 | 13806 | GOES16 | ||
| C5.1 | 12:49 | 13807 | GOES16 | ||
| C6.1 | 13:08 | 13807 | GOES16 | ||
| M1.3 | 13:25 | 13807 | GOES16 | ||
| C6.5 | 13:50 | 13807 | GOES16 | ||
| C7.8 | 14:18 | 13806 | GOES16 | ||
| C5.4 | 14:44 | S10097 | GOES16 | ||
| C7.8 | 14:50 | S10097 | GOES16 | ||
| C8.6 | 14:57 | 13807 | GOES16 | ||
| C7.0 | 15:09 | 13807 | GOES16 | ||
| C4.4 | 16:08 | 13807 | GOES16 | ||
| C3.3 | 17:22 | 13807 | GOES16 | ||
| C4.2 | 17:59 | 13807 | GOES16 | ||
| C3.7 | 18:20 | 13807 | GOES16 | ||
| C6.5 | 18:39 | 13807 | GOES16 | simultaneous flare in AR 13813 | |
| C4.6 | 19:32 | 13807 | GOES16 | ||
| C4.7 | 20:57 | 13807 | GOES16 | ||
| C3.3 | 22:37 | 13807 | GOES16 | ||
| C6.6 | 23:43 | 13807 | GOES16 | ||
| C4.0 | 00:05 | 13807 | GOES16 |
September 3-5: No obviously Earth directed CMEs were observed. An impressive backsided full halo CME was observed in LASCO C3 imagery after 07h UT. Given the material distribution the origin was likely 6 days behind the northwest limb at about N10.
[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 northern hemisphere coronal hole (CH1240) was in an Earth facing position on September 3-4.
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 poor.
The geomagnetic field is expected to be at mostly quiet on September 6-8 with a chance of unsettled intervals on September 6-7 due to weak effects from CH1240.
| 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 | ||||||||||
| 13803 | 2024.08.25 2024.08.26 |
N16W65 | location: N16W62 | ||||||||
| 13804 | 2024.08.25 2024.08.26 |
1 | S24W70 | 0001 | AXX |
 |
location: S27W69 | ||||
| 13805 | 2024.08.26 | N08W77 | location: N08W68 | ||||||||
| S10060 | 2024.08.26 | S07W50 | |||||||||
| 13807 | 2024.08.27 2024.08.30 |
10 | 6 | 2 | S15W86 | 0330 | EKI | CAO |
 |
 |
location: S18W79 rotated mostly out of view |
| 13806 | 2024.08.27 2024.08.28 |
39 | 66 | 29 | S12W37 | 0280 | EKC | FAC |
 |
 |
beta-gamma-delta location: S11W38 area: 0400 |
| S10065 | 2024.08.28 | N21W54 | |||||||||
| S10066 | 2024.08.28 | 3 | 1 | N23W52 | 0007 | BXO |
 |
 |
|||
| S10068 | 2024.08.28 | N01W53 | |||||||||
| 13808 | 2024.08.29 2024.08.30 |
10 | 8 | 3 | S10W27 | 0090 | DSI | CAO |
 |
 |
|
| S10071 | 2024.08.29 | N17W48 | |||||||||
| S10072 | 2024.08.29 | S06W51 |
 |
||||||||
| 13812 | 2024.08.29 2024.09.02 |
N14W10 |
 |
||||||||
| S10076 | 2024.08.30 | 24 | 6 | S10W05 | 0040 | CRI |
 |
 |
|||
| 13809 | 2024.08.30 | S21W30 |
 |
location: S19W31 | |||||||
| 13810 | 2024.08.31 2024.08.31 |
N16W31 |
location: N16W19 |
||||||||
| 13811 | 2024.08.31 2024.08.31 |
12 | 42 | 24 | S11E04 | 0240 | DSI | DKC |
 |
 |
beta-gamma area: 0390 location: S10E07 |
| S10081 | 2024.08.31 | S19W07 | |||||||||
| 13813 | 2024.09.01 2024.09.02 |
35 | 39 | 26 | S23E21 | 0370 | FKC | EAC |
 |
 |
beta-gamma-delta location: S21E23 area: 0490 SWPC includes AR S10087 |
| S10083 | 2024.09.01 | N07W43 | |||||||||
| S10084 | 2024.09.01 | 5 | 2 | N13E18 | 0012 | BXO |
 |
 |
|||
| S10086 | 2024.09.02 | 2 | N08E10 | 0004 | BXO |
 |
 |
||||
| S10087 | 2024.09.02 | 33 | 16 | S27E38 | 0480 | FKO |
 |
 |
|||
| S10088 | 2024.09.02 | N26W35 | |||||||||
| S10089 | 2024.09.02 | S32W13 | |||||||||
| S10090 | 2024.09.03 | N22W19 | |||||||||
| 13814 | 2024.09.04 2024.09.04 |
1 | 3 | 2 | N16E61 | 0180 | HSX | HHX |
 |
 |
area: 0420 location: N15E65 |
| S10092 | 2024.09.04 | S02W14 |
 |
||||||||
| S10093 | 2024.09.04 | S07E55 |
 |
||||||||
| S10094 | 2024.09.05 | 5 | 3 | S10E35 | 0020 | CRO |
 |
||||
| S10095 | 2024.09.05 | 7 | 2 | N22E18 | 0010 | BXO |
 |
||||
| S10096 | 2024.09.05 | 2 | 1 | N15E48 | 0004 | BXO |
 |
||||
| S10097 | 2024.09.05 | 2 | S12E66 | 0002 | AXX |
 |
|||||
| Total spot count: | 107 | 248 | 117 | ||||||||
| Sunspot number: | 167 | 408 | 247 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 152 | 304 | 172 | (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): | 184 | 224 | 198 | ||||||||
| 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 |
| 2022.12 | 147.9 | 143.4 | 112.8 | 106.7 (+5.5) | 10.99 |
| 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 | (143.3 projected, +6.5) | 11.03 |
| 2024.04 | 161.3 | 162.6 | 136.5 | (147.8 projected, +4.5) | 9.69 |
| 2024.05 | 187.7 | 191.9 | 171.7 | (152.6 projected, +4.8) | 23.56 (SC25 peak) |
| 2024.06 | 184.3 | 190.2 | 164.2 | (156.5 projected, +4.0) | 10.24 |
| 2024.07 | 196.6 |
203.0 | 196.5 | (158.3 projected, +1.8) | 7.13 |
| 2024.08 | 246.1 (cycle peak) |
252.2 | 215.5 (SC25 peak) | (158.7 projected, +0.4) | 15.8 |
| 2024.09 | 238.3 (1) | 26.9 (2A) / 161.4 (2B) / 216.1 (2C) | (160.8 projected, +2.1) | (8.5) | |
| 2024.10 | (162.7 projected, +1.9) | ||||
| 2024.11 | (160.7 projected, -2.0) | ||||
| 2024.12 | (156.4 projected, -4.3) | ||||
| 2025.01 | (150.3 projected, -6.1) | ||||
| 2025.02 | (143.0 projected, -7.3) | ||||
| 2025.03 | (136.2 projected, -6.8) | ||||
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
Sunspot counts in July 2024 were the highest we've seen for a single month during solar cycle 25. The first part of August has seen very high sunspot counts, and there more than a remote possibility that we'll see activity in August approaching the most active months of solar cycle 23. With at least 4 consecutive months of high sunspot counts the projected peak for the smoothed ISN (365 days smoothing) has increased significantly to above 160. The month of the peak is currently 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.
