The geomagnetic field was at quiet to minor storm levels on July 31 due to CME effects. The high latitude magnetometer at Andenes recorded quiet to minor storm levels. The above 10 MeV proton flux was at background levels at the end of the day. A weak solar wind shock was observed at ACE at 10:40, while a slightly stronger solar wind shock was recorded at 13:46 UT, likely the arrivals of the July 28 and 29 CMEs.
Solar flux density measured at 20h UT on 2.8 GHz was 235.1 - increasing 61.3 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 164.97. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 164.97 on January 31, 2024). The Potsdam WDC planetary A index was 14 (STAR Ap - based on the mean of three hour interval ap indices: 14.4). Three hour interval K indices: 21112454 (planetary), ******** (Boulder), 22113455 (Andenes).
The background x-ray flux is at the class C8 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 17 active regions using 2K resolution (SN: 486) and in 15 active regions using 1K resolution (SN: 320) SDO/HMI images.
AR 13763 [N04W49] was quiet and stable.
AR 13764 [S03W43] was quiet and stable and displayed wider separation
from AR 13766
AR 13765 [S12W33] decayed significantly and was mostly quiet.
AR 13766 [S07W41] decayed losing area and spots, and lost some
magnetic complexity.
AR 13767 [S08W26] developed slowly and produced a few flares.
AR 13768 [S16W69] is a compact and complex spot group and was the
most active region on the visible disk. Further major flares are possible.
AR 13769 [N22E11] was quiet and stable.
AR 13770 [N07W29] decayed losing area and spots. The magnetic delta
configurations became smaller. Minor M class flares are possible.
AR 13772 [S24E46] developed slowly and produced several flares. A
major flare is possible.
AR 13773 [S07W57] gained a few spots and was mostly quiet after an M
flare early in the day.
New AR 13774 [S07E69] rotated into view on July 30 and was numbered
by SWPC the next day. This is a large and compact spot group with major
flare potential.
New AR 13775 [N17E59] rotated into view on July 30 and received its
NOAA number the following day.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S9966 [N30W06] was quiet and stable.
S9977 [N05E08] was quiet and stable.
New region S9979 [N25W48] emerged before noon, then decayed
slowly.
New region S9980 [N09E48] emerged with tiny
spots.
New region S9981 [S19W21] emerged with tiny spots.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C5.4 | 00:23 | 13773 | GOES16 | ||
| C6.5 | 00:41 | 13772 | GOES16 | ||
| C4.1 | 01:15 | 13774 | GOES16 | ||
| C3.5 | 01:35 | 13772 | GOES16 | ||
| M1.9 | 01:50 | 13773 | GOES16 | ||
| C3.4 | 02:20 | 13774 | GOES16 | ||
| C4.8 | 02:41 | 13770 | GOES16 | ||
| C4.2 | 03:18 | 13772 | GOES16 | ||
| C4.6 | 04:35 | 13773 | GOES16 | ||
| C6.1 | 04:51 | 13766 | GOES16 | ||
| M4.8 | 05:23 | 13774 | GOES16 | ||
| C9.8 | 06:02 | 13774 | GOES16 | ||
| C8.4 | 06:23 | 13768 | GOES16 | ||
| M7.7 | 06:46 | 13768 | GOES16 | ||
| M1.5 | 07:31 | 13770 | GOES16 | ||
| C6.6 | 08:42 | 13772 | GOES16 | ||
| C6.0 | 09:06 | 13772 | GOES16 | ||
| C5.3 | 09:44 | 13775 | GOES16 | simultaneous flare in AR S9925 | |
| C9.3 | 10:21 | N10W20 | 13770 | GOES16 | simultaneous flare in AR 13772 |
| C8.9 | 10:35 | southwest limb | S9925 | GOES16 | simultaneous flare in AR 13767 |
| C6.8 | 11:33 | 13774 | GOES16 | ||
| C5.0 | 12:30 | southwest limb | S9925 | GOES16 | simultaneous flare in AR 13775 |
| C6.9 | 12:40 | 13772 | GOES16 | ||
| M6.0 | 13:05 | 13772 | GOES16 | simultaneous flares in ARs 13768 and 13766 | |
| M4.4 | 13:22 | S9925 | GOES16 | ||
| M4.4 | 13:32 | 13774 | GOES16 | attributed to AR 13772 by SWPC, however, that was likely related to the M6 flare | |
| M3.0 | 13:54 | 13766 | GOES16 | ||
| C9.7 | 14:45 | 13774 | GOES16 | ||
| M1.0 | 16:24 | 13768 | GOES18 | simultaneous flare in AR 13767 | |
| M1.4 | 16:31 | 13774 | GOES18 | simultaneous flares in ARs 13767 and S9925 | |
| C5.8 | 17:05 | 13768 | GOES18 | ||
| C5.8 | 17:12 | 13773 | GOES18 | ||
| C5.6 | 17:19 | 13772 | GOES18 | ||
| C5.7 | 17:34 | 13774 | GOES18 | ||
| M5.4 | 18:37 | S15W71 | 13768 | GOES16 | LDE, moderate type II and IV radio sweeps, CME (maybe very faint halo CME) |
| C9.0 | 20:01 | 13765/13767 | GOES16 | ||
| M1.0 | 20:06 | 13774 | GOES16 | ||
| C6.6 | 20:53 | 13770 | GOES16 | simultaneous flare in AR 13774 | |
| C8.6/1F | 21:15 | S24E50 | 13772 | GOES16 | |
| M1.2 | 21:54 | 13767 | GOES16 | incorrectly attributed to AR 13768 by SWPC | |
| C9.1 | 22:07 | 13767 | GOES16 | ||
| C7.7 | 22:22 | 13768 | GOES16 | ||
| M1.0 | 22:49 | 13774 | GOES16 | ||
| C7.9 | 23:26 | 13772 | GOES16 | ||
| C6.7 | 23:58 | 13772 | GOES16 | simultaneous flare in AR 13768 |
July 30-31: No obviously Earth directed CMEs were observed.
July 29: A partial halo CME was observed after an M8.7 flare in AR
S9925
peaking at 12:55 UT. Components of this CME may have reached
Earth on July 31.
[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 trans equatorial coronal hole (CH1233) rotated across the central meridian on July 30-31, however, CH1233 was in decay most of July 30 and no significant disturbance is expected.
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 quiet to minor storm levels on August 1 due to CME effects. Effects from CH1233 could reach Earth on August 2-3 and cause quiet to active levels.
| 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 | ||||||||||
| 13762 | 2024.07.19 | 7 | S11W87 | 0180 | DAC |
location: S13W75 SWPC includes AR S9925 in this AR rotated out of view |
|||||
| 13763 | 2024.07.21 2024.07.22 |
1 | 3 | 1 | N05W49 | 0060 | HSX | CSO |
 |
 |
location: N04W49 area: 0200 |
| S9936 | 2024.07.21 | N22W52 | |||||||||
| 13764 | 2024.07.22 2024.07.22 |
3 | 1 | 1 | S03W47 | 0070 | CSO | HSX |
 |
 |
area: 0190 |
| 13765 | 2024.07.23 2024.07.23 |
28 | 32 | 19 | S11W33 | 0450 | DKC | DAC |
 |
 |
beta-gamma-delta area: 0560 location: S12W33 |
| S9948 | 2024.07.23 | N36W54 | |||||||||
| S9953 | 2024.07.23 | S19W51 | |||||||||
| 13766 | 2024.07.24 | 26 | 55 | 31 | S07W40 | 0220 | EAI | EAI |
 |
 |
beta-gamma location: S07W41 area: 0360 |
| 13767 | 2024.07.25 | 15 | 44 | 23 | S09W24 | 0130 | DAI | DAI |
 |
 |
beta-gamma area: 0300 location: S08W26 |
| 13768 | 2024.07.25 2024.07.26 |
22 | 33 | 19 | S16W71 | 0450 | FKC | FKC |
 |
 |
beta-gamma-delta location: S16W69 area: 0640 |
| 13771 | 2024.07.25 2024.07.29 |
N01W73 | location: N00W69 | ||||||||
| S9959 | 2024.07.25 | S05W54 | |||||||||
| 13769 | 2024.07.25 2024.07.26 |
1 | 13 | 5 | N22E10 | 0080 | HSX | CSO |
 |
 |
location: N22E11 area: 0220 |
| 13770 | 2024.07.27 2024.07.28 |
12 | 31 | 17 | N07W30 | 0340 | DHO | DSC |
 |
 |
beta-delta location: N07W29 area: 0390 |
| S9966 | 2024.07.28 | 2 | N30W06 | 0003 | BXO |
 |
 |
||||
| 13772 | 2024.07.29 2024.07.30 |
12 | 35 | 18 | S25E48 | 0240 | EAI | EAC |
 |
 |
beta-gamma-delta area: 0500 location: S24E46 |
| S9968 | 2024.07.29 | N34E04 | |||||||||
| S9969 | 2024.07.29 | N08E05 |
 |
||||||||
| S9970 | 2024.07.29 | N11W15 | |||||||||
| S9971 | 2024.07.29 | N25W36 | |||||||||
| S9972 | 2024.07.29 | N24W10 | |||||||||
| S9973 | 2024.07.29 | S12W11 | |||||||||
| 13775 | 2024.07.30 2024.07.31 |
4 | 10 | 5 | N17E60 | 0040 | CSO | DRO |
 |
 |
location: N17E59 |
| 13773 | 2024.07.30 2024.07.30 |
8 | 17 | 7 | S06W58 | 0030 | CRO | DRI |
 |
 |
beta-gamma area: 0050 |
| 13774 | 2024.07.30 | 2 | 23 | 15 | S06E70 | 0250 | EKI | EKC |
 |
 |
beta-gamma location: S07E69 area: 0960 |
| S9977 | 2024.07.30 | 4 | 2 | N05E08 | 0010 | CRO |
 |
 |
|||
| S9978 | 2024.07.30 | N31W21 |
 |
||||||||
| S9979 | 2024.07.31 | 2 | N25W48 | 0002 | BXO |
 |
|||||
| S9980 | 2024.07.31 | 6 | 4 | N09E48 | 0030 | DRO |
 |
||||
| S9981 | 2024.07.31 | 5 | 3 | S19W21 | 0010 | BXO |
 |
||||
| Total spot count: | 141 | 316 | 170 | ||||||||
| Sunspot number: | 271 | 486 | 320 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 224 | 388 | 242 | (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): | 298 | 267 | 256 | ||||||||
| 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 | 196.9 (1) | 203.0 | 188.8 (2A/B) / 219.0 (2C) | (150.9 projected, +1.6) | (7.1) |
| 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.
