The geomagnetic field was at quiet to unsettled levels on July 25. A disturbance arrived at ACE just after 13h UT with a quick increase in solar wind speed and temperature. Initially and until 04h UT on July 26 the disturbance was in an away sector. Solar wind speed has increased slowly and reached 600 km/sec on July 26. The source of this disturbance is uncertain, maybe a transient and a coronal hole speed stream combining. 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.
Solar flux density measured at 20h UT on 2.8 GHz was 167.2 - decreasing 13.5 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 164.36. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 164.36 on January 24, 2024). The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.5). Three hour interval K indices: 12112233 (planetary), ******** (Boulder), 11112435 (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 21 active regions using 2K resolution (SN: 445) and in 15 active regions using 1K resolution (SN: 251) SDO/HMI images.
AR 13751 [S07W81] rotated mostly out of view. C1 flare: C1.9 @ 01:30,
C1.6 @ 05:41, C1.9 @ 08:05, C1.7 @ 16:07, C1.5 @ 21:27 UT
AR 13755 [N03W62] decayed slowly and quietly.
AR 13756 [S17W52] was quiet and stable.
AR 13757 [N18W48] decayed slowly and quietly.
AR 13761 [S09W58] decayed slowly and was mostly quiet. C1 flares:
C1.7 @ 21:15 UT
AR 13762 [S13E04] decayed and lost the magnetic delta. SWPC includes
AR S9925 in this spot group.
AR 13763 [N03E32] gained some tiny spots and was quiet.
AR 13764 [S04E38] was mostly quiet and stable.
AR 13765 [S12E46] was mostly quiet and stable. The trailing spot
section was split off into AR 13767. C1 flares: C1.7 @ 18:00 UT
New AR 13767 [S09E54] was formerly the trailing spot section of AR
13765. C1 flares: C1.7 @ 05:03, C1.9 @ 09:44, C1.4 @ 14:03, C1.5 @ 14:47,
C1.6 @ 22:40 UT
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S9925 [S11W07] gained spots and has major polarity intermixing. M
class flaring is possible. C1 flares: C1.8 @ 04:21, C1.8 @ 06:14, C1.7 @
12:55, C1.9 @ 20:46 UT
S9941 [N24W15] was quiet and stable.
S9943 [S19W35] was quiet and stable.
S9953 [S28E28] was quiet and stable.
S9956 [N20W71] developed early in the day, then decayed slowly after
noon.
New region S9957 [S16E13] emerged with tiny
spots.
New region S9958 [S00E11] emerged with tiny spots.
New region S9959 [S00E30] emerged with tiny spots.
New region S9960 [N24E23] was observed with tiny spots in an
old plage area.
New region S9961 [N22E87] rotated partly into view.
New region S9962 [N07W41] emerged with a tiny
spot.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C8.4/1F | 00:41 | S11E08 | S9925 | GOES16 | simultaneous flare in AR 13762 |
| C3.8 | 01:11 | S9925 | GOES16 | ||
| C5.1 | 01:29 | S9925 | GOES16 | ||
| C9.1/1F | 02:03 | S13E14 | 13762 | GOES16 | |
| C3.4 | 02:21 | 13767 | GOES16 | simultaneous flare in AR S9961 | |
| C2.0 | 02:40 | 13762 | GOES16 | ||
| C2.1 | 04:33 | 13762 | GOES16 | ||
| C2.1 | 05:23 | S10E66 (SDO/AIA) | 13767 | GOES16 | |
| C2.1 | 05:26 | 13762 | GOES16 | incorrectly attributed to AR 13766 by SWPC | |
| C2.1 | 07:14 | GOES16 | |||
| C2.6 | 11:00 | 13764 | GOES16 | ||
| C2.9 | 11:15 | 13761 | GOES16 | attributed to AR 13764 by SWPC | |
| C2.7 | 11:30 | 13767 | GOES16 | ||
| C3.0 | 12:32 | 13751 | GOES16 | moderate type II radio sweep, attributed to AR 13761 by SWPC | |
| C2.2 | 12:41 | 13764 | GOES16 | ||
| C2.1 | 13:32 | S12W00 | S9925 | GOES16 | |
| M1.3 | 15:37 | 13751 | GOES16 | strong type II radio sweep | |
| C2.1 | 17:06 | S07W83 | 13751 | GOES16 | |
| C2.0 | 18:34 | 13761 | GOES16 | ||
| C2.3 | 18:49 | S9925 | GOES16 | simultaneous flare in AR 13764 |
July 23-24: No obviously Earth directed CMEs were observed.
July 25: A filament eruption began at approximately 00:30 UT and
triggered activity in ARs 13762 and AR S9925 and areas to the north of those
two spot groups well into the northern hemisphere. The first traces of a CME
was observed over the northern limbs and the north pole starting at 00:36
UT. Due to the short time interval between these observations, it is likely
that the CME was farsided. A full halo CME was observed
later on in LASCO imagery.
[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 active on July 26-28.
| 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 | ||||||||||
| 13751 | 2024.07.13 2024.07.13 |
2 | 1 | S08W84 | 0050 | DAO | AXX |
 |
 |
location: S07W83 area: 0005 |
|
| 13752 | 2024.07.13 2024.07.14 |
N22W83 |
location: N24W70 |
||||||||
| 13754 | 2024.07.14 | N25W66 |
 |
location: N25W58 |
|||||||
| 13755 | 2024.07.15 2024.07.16 |
1 | 1 | 1 | N02W63 | 0010 | AXX | AXX |
 |
 |
location: N03W62 |
| 13756 | 2024.07.15 2024.07.16 |
1 | 1 | 1 | S17W52 | 0060 | HSX | HSX |
 |
 |
area: 0090 |
| 13757 | 2024.07.15 2024.07.16 |
1 | 2 | 1 | N16W46 | 0010 | HRX | HRX |
 |
 |
location: N18W48 area: 0020 |
| 13761 | 2024.07.18 2024.07.19 |
4 | 14 | 7 | S10W70 | 0090 | HSX | DAO |
 |
 |
area: 0260 |
| S9925 | 2024.07.19 | 71 | 37 | S11W07 | 0380 | EAC |
 |
 |
beta-gamma-delta (including former leading spot section of AR 13762 due to the complex spot layout) |
||
| 13762 | 2024.07.19 | 35 | 25 | 14 | S12W04 | 0230 | FAC | DRI |
 |
 |
area: 0080 location: S13E04 SWPC includes AR S9925 in this AR |
| S9927 | 2024.07.19 | N10W21 | |||||||||
| S9928 | 2024.07.19 | S04W40 | |||||||||
| S9931 | 2024.07.20 | N19W03 |
 |
||||||||
| 13763 | 2024.07.21 2024.07.22 |
2 | 14 | 7 | N03E34 | 0100 | CSO | DSO |
 |
 |
location: N03E32 area: 0240 |
| S9936 | 2024.07.21 | N22E26 | |||||||||
| S9937 | 2024.07.21 | N28E06 | |||||||||
| S9938 | 2024.07.21 | S25W44 | |||||||||
| 13764 | 2024.07.22 2024.07.22 |
4 | 38 | 12 | S04E37 | 0040 | CSO | EAI |
 |
 |
area: 0160 location: S04E38 SWPC has split the easternmost spots into AR 13766 |
| S9941 | 2024.07.22 | 13 | 3 | N24W15 | 0025 | BXO |
 |
 |
|||
| S9942 | 2024.07.22 | N08W25 | |||||||||
| S9943 | 2024.07.22 | 3 | S19W35 | 0004 | AXX |
 |
 |
||||
| S9944 | 2024.07.22 | S03W31 | |||||||||
| S9945 | 2024.07.22 | S18W35 | |||||||||
| 13765 | 2024.07.23 2024.07.23 |
1 | 8 | 4 | S11E45 | 0060 | HSX | CAO |
 |
 |
area: 0230 location: S11E61 trailing spot section split off into AR 13767 |
| S9948 | 2024.07.23 | N29E06 |
 |
||||||||
| S9949 | 2024.07.23 | S05W37 |
 |
||||||||
| S9950 | 2024.07.23 | N20W07 | |||||||||
| S9951 | 2024.07.23 | N13E07 | |||||||||
| S9952 | 2024.07.23 | S28W02 | |||||||||
| S9953 | 2024.07.23 | 6 | S28E28 | 0008 | BXO |
 |
 |
||||
| S9954 | 2024.07.23 | S02W13 |
 |
||||||||
| 13766 | 2024.07.24 | 5 | S08E51 | 0010 | BXO | trailing spot section of AR 13764 | |||||
| 13767 | 2024.07.25 | 5 | 18 | 7 | S09E57 | 0060 | CAO | CAO |
 |
area: 0080 location: S09E54 |
|
| S9956 | 2024.07.24 | 2 | N20W71 | 0002 | BXO |
 |
 |
||||
| S9957 | 2024.07.25 | 6 | 4 | S16E13 | 0020 | CRO |
 |
||||
| S9958 | 2024.07.25 | 2 | 1 | S00E11 | 0006 | AXX |
 |
||||
| S9959 | 2024.07.25 | 6 | 1 | S00E30 | 0013 | BXO |
 |
||||
| S9960 | 2024.07.25 | 2 | N24E23 | 0005 | BXO |
 |
|||||
| S9961 | 2024.07.25 | 1 | N22E87 | 0100 | HSX |
 |
|||||
| S9962 | 2024.07.25 | 1 | 1 | N24W15 | 0002 | AXX |
 |
||||
| Total spot count: | 61 | 235 | 101 | ||||||||
| Sunspot number: | 171 | 445 | 251 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 104 | 284 | 150 | (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): | 188 | 245 | 201 | ||||||||
| 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 | (128.9 projected, -0.5) | 5.46 |
| 2024.02 | 172.5 | 168.3 | 123.0 | (129.4 projected, +0.5) | 5.31 |
| 2024.03 | 154.4 | 152.9 | 103.7 | (130.3 projected, +0.9) | 11.03 |
| 2024.04 | 161.3 | 162.6 | 136.5 | (131.0 projected, +0.7) | 9.69 |
| 2024.05 | 187.7 (cycle peak) |
191.9 | 171.7 (SC25 peak) | (133.2 projected, +2.2) | 23.56 (SC25 peak) |
| 2024.06 | 184.3 | 190.2 | 164.2 | (134.9 projected, +1.7) | 10.24 |
| 2024.07 | 193.7 (1) | 147.2 (2A) / 182.5 (2B) / 212.5 (2C) | (134.7 projected, -0.2) | (5.5) | |
| 2024.08 | (134.1 projected, -0.6) | ||||
| 2024.09 | (134.4 projected, +0.1) | ||||
| 2024.10 | (134.3 projected, -0.1) | ||||
| 2024.11 | (132.3 projected, -2.0) | ||||
| 2024.12 | (128.0 projected, -4.3) | ||||
| 2025.01 | (124.0 projected, -4.0) | ||||
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.
