The geomagnetic field was at quiet to unsettled levels on July 28. The high latitude magnetometer at Andenes recorded quiet to active 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 214.9 - increasing 44.3 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 164.53. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 164.53 on January 28, 2024). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.5). Three hour interval K indices: 11122132 (planetary), ******** (Boulder), 32223244 (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 15 active regions using 2K resolution (SN: 441) and in 13 active regions using 1K resolution (SN: 285) SDO/HMI images.
AR 13762 [S13W36] decayed slowly and quietly.
AR 13763 [N04W08] was quiet and stable.
AR 13764 [S03W03] decayed slowly and quietly. The expansion of AR
13766 is such that the two ARs could merge.
AR 13765 [S11E08] developed further and is a compact, complex region
with a magnetic delta configuration and major flare potential.
AR 13766 [S06W00] developed further and still has major flare
potential. The region has small magnetic delta configurations.
AR 13767 [S09E14] was mostly unchanged and could produce a minor M
class flare.
AR 13768 [S16W27] developed quickly, has multiple magnetic delta
configurations and major flare potential.
AR 13769 [N22E50] was quiet and stable.
New region 13770 [N08E10] emerged on July 27 and was numbered the
next day as the spot group developed very quickly. There's a small magnetic
delta configuration in a small northern penumbra. A major flare is possible.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S9925 [S11W49] decayed slowly and produced several M flares. The spot
group still has multiple magnetic delta configurations and further M class
flaring is likely.
S9948 [N36W15] was quiet ands stable.
S9953 [S21W15] was quiet and stable.
S9958 [N00W29] developed slowly and quietly.
S9960 [N22W22] reemerged with a tiny spot.
New region S9966 [N30E33] emerged with tiny spots.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C3.8 | 00:19 | S9925 | GOES16 | ||
| M7.8/2B | 01:51 | 13766 | GOES16 | strong type II radio sweep | |
| M9.9 | 01:57 | 13766 | GOES16 | full halo CME | |
| C7.3 | 03:09 | S9925 | GOES16 | ||
| C8.1 | 03:15 | 13766 | GOES16 | ||
| C8.8 | 03:31 | S9925 | GOES16 | simultaneous flares in AR 13770 and AR 13768 | |
| M1.5 | 03:47 | S10W37 | S9925 | GOES16 | |
| C5.5 | 05:00 | S9925 | GOES16 | ||
| C4.3 | 05:28 | 13770 | GOES16 | simultaneous flare in AR 13768 | |
| C4.9 | 06:10 | S07E14 | 13766 | GOES16 | simultaneous flare in AR S9925 |
| C5.0 | 07:27 | GOES16 | |||
| C5.7 | 07:57 | S9925 | GOES16 | ||
| C6.0 | 08:13 | 13765 | GOES16 | ||
| C6.0 | 08:50 | 13765 | GOES16 | ||
| C6.1 | 08:58 | S9925 | GOES16 | ||
| C8.9 | 09:58 | 13765 | GOES16 | ||
| M1.0 | 10:07 | S9925 | GOES16 | ||
| M7.7/1B | 10:42 | S11W40 | S9925 | GOES16 | |
| M1.6 | 11:56 | S9925 | GOES16 | ||
| M2.6 | 12:50 | S08E23 (SDO/AIA) | 13767 | GOES16 | SWPC incorrectly reports the location as S09E15 and AR 13766 |
| M1.2 | 13:19 | S9925 | GOES16 | ||
| M1.0 | 13:39 | 13770 | GOES16 | simultaneous flare in AR 13766 | |
| M1.5 | 14:06 | 13768 | GOES16 | ||
| M1.6 | 14:22 | 13768 | GOES16 | ||
| M1.0 | 15:26 | 13768/13762/S9925 | GOES16 | simultaneous flare in AR 13770 | |
| C8.3 | 16:00 | S06E07 | 13766 | GOES16 | |
| C5.7 | 17:16 | S08E20 | 13767 | GOES16 | |
| C5.1 | 17:24 | 13765 | GOES16 | ||
| M1.3/1F | 18:26 | S13W30 | 13768 | GOES16 | simultaneous flare in AR 13766 |
| C4.0 | 20:16 | 13766 | GOES16 | simultaneous flare in AR 13770 | |
| C4.1 | 20:20 | 13766 | GOES16 | ||
| M1.9/1N | 20:36 | S10W47 | S9925 | GOES16 | simultaneous flare in AR 13766 |
| C6.0 | 21:39 | 13770 | GOES16 | ||
| C6.9 | 22:45 | S09W44 | S9925 | GOES16 | |
| C4.4 | 23:52 | N08E14 | 13770 | GOES16 |
July 28: A full halo CME was observed after an M9.9 flare in AR 13766
peaking at 01:57 UT. This CME will most likely reach Earth on July 30 and
cause unsettled to severe storm conditions. Multiple other CMEs were
observed during the day, however, it is uncertain if any of those are Earth
directed.
July 27: A full halo CME was observed after an M3.1 flare in AR S9925
peaking at 05:46 UT. The CME could reach Earth on July 29 and cause
unsettled to major storm conditions.
July 26: 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]
No obvious coronal holes are currently in or near Earth facing locations.
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 quiet to severe storm on July 29-31 due to CME effects.
| 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 | ||||||||||
| 13756 | 2024.07.15 2024.07.16 |
1 | S17W92 | 0030 | HSX |
 |
rotated out of view | ||||
| 13757 | 2024.07.15 2024.07.16 |
N18W88 |
 |
||||||||
| S9925 | 2024.07.19 | 47 | 26 | S11W49 | 0400 | EAC |
 |
 |
beta-gamma-delta (including former leading spot section of AR 13762) |
||
| 13762 | 2024.07.19 | 25 | 7 | 2 | S11W45 | 0440 | FKC | BXO |
 |
 |
area: 0015 location: S13W36 SWPC includes AR S9925 in this AR |
| S9931 | 2024.07.20 | N19W42 | |||||||||
| 13763 | 2024.07.21 2024.07.22 |
2 | 16 | 5 | N02W06 | 0120 | CSO | DSO |
 |
 |
location: N04W08 area: 0200 |
| S9936 | 2024.07.21 | N22W13 | |||||||||
| S9937 | 2024.07.21 | N28W33 | |||||||||
| 13764 | 2024.07.22 2024.07.22 |
2 | 6 | 2 | S03W06 | 0090 | HSX | CSO |
 |
 |
area: 0180 |
| S9941 | 2024.07.22 | N31W48 |
 |
||||||||
| 13765 | 2024.07.23 2024.07.23 |
15 | 28 | 20 | S11E07 | 0380 | DKC | DKC |
 |
 |
area: 0780 location: S11E08 |
| S9948 | 2024.07.23 | 3 | N36W15 | 0004 | AXX |
 |
 |
||||
| S9950 | 2024.07.23 | N20W46 | |||||||||
| S9951 | 2024.07.23 | N13W32 | |||||||||
| S9952 | 2024.07.23 | S28W41 | |||||||||
| S9953 | 2024.07.23 | 6 | S21W15 | 0010 | BXO |
 |
 |
||||
| S9954 | 2024.07.23 | S02W52 | |||||||||
| 13766 | 2024.07.24 | 13 | 51 | 29 | S07E04 | 0150 | DAC | EKC |
 |
 |
beta-gamma-delta location: S06W00 area: 0440 |
| 13767 | 2024.07.25 | 10 | 34 | 23 | S11E19 | 0200 | DSI | DSI |
 |
 |
beta-gamma area: 0240 location: S09E14 |
| 13768 | 2024.07.25 2024.07.26 |
10 | 46 | 21 | S16W29 | 0200 | DAI | EKC |
 |
 |
beta-gamma-delta location: S16W27 area: 0510 |
| S9958 | 2024.07.25 | 8 | 4 | N00W29 | 0030 | DRO |
 |
 |
|||
| S9959 | 2024.07.25 | S05W15 |
 |
||||||||
| S9960 | 2024.07.25 | 1 | 1 | N22W22 | 0003 | AXX |
 |
||||
| 13769 | 2024.07.25 2024.07.26 |
1 | 3 | 2 | N23E49 | 0100 | HSX | CSO |
 |
 |
location: N22E50 area: 0210 |
| S9962 | 2024.07.25 | N24W54 | |||||||||
| S9963 | 2024.07.26 | N08E15 | this AR merged with AR 13770 due to the rapid expansion of 13770 | ||||||||
| 13770 | 2024.07.27 2024.07.28 |
10 | 32 | 18 | N07E08 | 0200 | DAI | DHC |
 |
 |
beta-gamma-delta location: N08E10 area: 0470 |
| S9966 | 2024.07.28 | 3 | 2 | N30E33 | 0007 | AXX |
 |
||||
| Total spot count: | 89 | 291 | 155 | ||||||||
| Sunspot number: | 189 | 441 | 285 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 149 | 359 | 223 | (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): | 208 | 243 | 228 | ||||||||
| 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 |
| 2022.10 | 133.5 | 132.7 | 95.5 | 98.9 (+2.4) | 11.16 |
| 2022.11 | 123.4 | 120.7 | 80.5 | 101.2 (+2.3) | 9.33 |
| 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 | (130.8 projected, +1.4) | 5.46 |
| 2024.02 | 172.5 | 168.3 | 123.0 | (134.1 projected, +3.3) | 5.31 |
| 2024.03 | 154.4 | 152.9 | 103.7 | (137.6 projected, +3.5) | 11.03 |
| 2024.04 | 161.3 | 162.6 | 136.5 | (141.2 projected, +3.6) | 9.69 |
| 2024.05 | 187.7 (cycle peak) |
191.9 | 171.7 (SC25 peak) | (145.6 projected, +4.4) | 23.56 (SC25 peak) |
| 2024.06 | 184.3 | 190.2 | 164.2 | (149.3 projected, +3.7) | 10.24 |
| 2024.07 | 193.7 (1) | 164.8 (2A) / 182.5 (2B) / 217.0 (2C) | (150.9 projected, +1.6) | (6.4) | |
| 2024.08 | (150.8 projected, -0.1) | ||||
| 2024.09 | (150.6 projected, -0.2) | ||||
| 2024.10 | (150.6 projected, -0.0) | ||||
| 2024.11 | (148.5 projected, -2.1) | ||||
| 2024.12 | (144.2 projected, -4.3) | ||||
| 2025.01 | (138.4 projected, -6.2) | ||||
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 June 2024 were almost at the level of May 2024 and the second highest month during solar cycle 25. Looking at the projected activity for the remainder of this year, solar max now looks likely to occur between May and October 2024. A big decrease in sunspot formation in July 2024 and over the next months could change the projected maximum to earlier in 2024 or even to December 2023.
--------------------------------------------------------------------------------------
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.
