The geomagnetic field was at quiet levels on July 21. The high latitude magnetometer at Andenes recorded quiet to unsettled 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 197.9 - decreasing 0.8 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 164.28. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 164.28 on January 21, 2024). The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.1). Three hour interval K indices: 10001122 (planetary), ******** (Boulder), 30012332 (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 20 active regions using 2K resolution (SN: 426) and in 15 active regions using 1K resolution (SN: 270) SDO/HMI images.
AR 13744 [N14W83] kept
its magnetic delta configuration and produced several C and M flares.
AR 13745 [S24W86] rotated mostly out of view.
AR 13749 [S32W36] was quiet and stable.
AR 13751 [S08W29] produced several C and one M flares. The spot group
still has several small magnetic delta configurations.
AR 13752 [N25W19] decayed slowly and quietly.
AR 13754 [N26W05] decayed slowly and quietly
AR 13755 [N04W07] decayed slowly and quietly.
AR 13756 [S18E00] was quiet and stable.
AR 13757 [N18E08] was quiet and stable.
AR 13759 [S06W51] was mostly quiet and stable.
AR 13760 [N20W47] decayed slowly and quietly.
AR 13761 [S10W13] was mostly quiet and stable.
AR 13762 [S13E57] developed significantly and gained a magnetic delta
configuration. The region has been very unstable early on July 22 producing
several M flares.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S9925 [S12E47] developed slowly and quietly.
S9931 [N20E52] developed slowly and quietly.
New region S9935 [N04E85] rotated into view with a mature spot.
New region S9936 [N22E70] emerged with a tiny spot.
New region S9937 [N28E58] was observed with tiny spots in an old
plage area.
New region S9938 [S25E08] emerged with a tiny spot.
New region S9939 [N09W17] emerged with a tiny spot.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C5.2 | 00:29 | southwest limb | 13745 | GOES16 | |
| C6.6 | 00:39 | behind northwest limb | GOES16 | ||
| C4.2 | 01:30 | 13751 | GOES16 | ||
| C3.7 | 01:41 | 13751 | GOES16 | ||
| C4.8 | 01:55 | 13751 | GOES16 | ||
| C7.4 | 02:07 | S07W13 | 13751 | GOES16 | |
| C5.2 | 02:37 | 13744 | GOES16 | ||
| C5.4 | 02:58 | 13744 | GOES16 | ||
| M1.4 | 03:55 | 13744 | GOES16 | ||
| C2.9 | 04:58 | 13751 | GOES16 | ||
| C4.3 | 05:44 | S10W13 | 13751 | GOES16 | |
| C3.9 | 06:59 | GOES16 | |||
| C6.0/1F | 07:43 | S07W18 | 13751 | GOES16 | |
| C2.7 | 08:08 | 13744 | GOES16 | ||
| M1.5 | 08:34 | 13751 | GOES16 | ||
| C5.3 | 08.50 | 13744 | GOES16 | ||
| C4.0 | 09:39 | 13762 | GOES16 | simultaneous flares in ARs 13744 and 13751 | |
| C4.1 | 10:17 | N14W74 | 13744 | GOES16 | |
| C3.1 | 10:38 | 13751 | GOES16 | ||
| C5.8 | 11:07 | S09W17 | 13751 | GOES16 | simultaneous flare in AR 13744 |
| C3.8 | 11:24 | 13757 | GOES16 | ||
| C4.8 | 12:08 | behind southwest limb | GOES16 | ||
| C5.4 | 12:18 | 13744 | GOES16 | ||
| C5.8 | 12:37 | 13751 | GOES16 | ||
| C4.5 | 13:31 | 13751 | GOES16 | ||
| C2.7 | 13:49 | 13751 | GOES16 | ||
| C2.6 | 14:17 | 13762 | GOES16 | ||
| C3.4 | 14:27 | 13762 | GOES16 | ||
| C3.0 | 14:40 | 13762 | GOES16 | ||
| C3.1 | 14:48 | 13762 | GOES16 | ||
| C2.7 | 15:13 | 13751 | GOES16 | ||
| C2.8 | 15:45 | behind southwest limb | GOES16 | ||
| C3.3 | 15:55 | behind northwest limb | GOES16 | ||
| C3.5 | 16:03 | 13751 | GOES16 | ||
| M1.0 | 16:31 | 13757 | GOES16 | full halo CME, moderate type II radio sweep | |
| C3.0 | 17:58 | 13751 | GOES16 | ||
| C4.7 | 20:12 | 13744 | GOES16 | ||
| C4.5 | 20:27 | 13744 | GOES16 | ||
| C4.3 | 20:49 | 13751 | GOES16 | ||
| C3.8 | 21:14 | 13762 | GOES16 | ||
| C3.2 | 21:43 | 13762 | GOES16 | ||
| C5.4 | 21:56 | 13762 | GOES16 | simultaneous flares in AR 13751 and from behind the southwest limb | |
| C3.7 | 22:23 | 13751 | GOES16 | simultaneous flare in AR 13762 | |
| M3.2 | 23:28 | 13744 | GOES16 |
July 19-20: No obviously Earth directed CMEs were observed.
July 21: AR 13757 produced an M1 flare at 16:31 UT. A filament
eruption was observed at that time in the vicinity of the region. At 17:00
UT a CME became visible over the north pole and the northeast limb, soon
after an asymmetrical full halo CME was visible in LASCO imagery. The CME
could reach Earth on July 24.
[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 fair to good. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet on July 22-23. Quiet to minor storm conditions are possible on July 24-25 due to effects from the July 21 CME.
| 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 | ||||||||||
| 13745 | 2024.07.08 2024.07.10 |
2 | 1 | S23W89 | 0030 | CRO | HRX |
 |
 |
location: S24W87 |
|
| 13744 | 2024.07.09 2024.07.09 |
5 | 4 | 3 | N15W83 | 0080 | DAI | DRI |
 |
 |
beta-delta |
| 13748 | 2024.07.10 2024.07.12 |
N15W68 |
 |
location: N17W64 |
|||||||
| 13747 | 2024.07.11 | 1 | S25W86 | 0030 | HAX | AR 13747 is the trailing polarity section of AR 13742, rotated out of view | |||||
| 13750 | 2024.07.12 2024.07.13 |
S20W49 |
 |
location: S20W40 |
|||||||
| 13749 | 2024.07.12 2024.07.13 |
4 | 1 | S33W38 | 0007 | AXX |
 |
 |
location: S32W36 | ||
| 13751 | 2024.07.13 2024.07.13 |
28 | 72 | 40 | S08W28 | 0380 | EKC | EAC |
 |
 |
beta-gamma-delta location: S08W29 |
| 13752 | 2024.07.13 2024.07.14 |
7 | 3 | N22W27 | 0013 | BXO |
 |
 |
location: N25W19 |
||
| 13754 | 2024.07.14 | 1 | 4 | 2 | N25W10 | 0010 | AXX | BXO |
 |
 |
location: N25W05 |
| 13760 | 2024.07.14 2024.07.18 |
1 | 4 | 2 | N20W46 | 0010 | AXX | BXO |
 |
 |
location: N20W47 |
| S9905 | 2024.07.14 | S35W52 | |||||||||
| S9907 | 2024.07.15 | N22W10 | |||||||||
| 13755 | 2024.07.15 2024.07.16 |
3 | 9 | 4 | N02W08 | 0030 | CSO | CRI |
 |
 |
location: N04W07 |
| 13756 | 2024.07.15 2024.07.16 |
1 | 1 | 1 | S17W00 | 0100 | HSX | HSX |
 |
 |
area: 0140 location: S18E00 |
| 13757 | 2024.07.15 2024.07.16 |
5 | 25 | 11 | N17E08 | 0040 | CAO | DAO |
 |
 |
area: 0070 location: N18E08 |
| 13759 | 2024.07.15 2024.07.17 |
8 | 23 | 12 | S06W50 | 0230 | DAO | DKO |
 |
 |
location: S06W54 area: 0300 |
| S9917 | 2024.07.16 | N19W15 | |||||||||
| S9918 | 2024.07.16 | N06W39 | |||||||||
| S9920 | 2024.07.17 | N14W40 | |||||||||
| 13761 | 2024.07.18 2024.07.19 |
17 | 34 | 23 | S10W15 | 0300 | DKI | DAC |
 |
 |
beta-gamma area: 0530 |
| S9923 | 2024.07.19 | S20W29 | |||||||||
| S9924 | 2024.07.19 | S24W38 | |||||||||
| S9925 | 2024.07.19 | 9 | 6 | S12E47 | 0040 | DRO |
 |
 |
|||
| 13762 | 2024.07.19 | 8 | 15 | 9 | S13E51 | 0130 | DAO | DAC |
 |
 |
beta-delta area: 0190 location: S13E57 |
| S9927 | 2024.07.19 | N10E31 | |||||||||
| S9928 | 2024.07.19 | S04E12 | |||||||||
| S9929 | 2024.07.19 | S35W25 | |||||||||
| S9930 | 2024.07.20 | N44W25 |
 |
||||||||
| S9931 | 2024.07.20 | 6 | 2 | N20E52 | 0012 | BXO |
 |
 |
|||
| S9933 | 2024.07.20 | S32W48 |
 |
||||||||
| S9935 | 2024.07.21 | 2 | 1 | N04E85 | 0200 | HSX |
 |
||||
| S9936 | 2024.07.21 | 1 | N22E78 | 0001 | AXX |
 |
|||||
| S9937 | 2024.07.21 | 3 | N28E58 | 0005 | BXO |
 |
|||||
| S9938 | 2024.07.21 | 1 | S25E08 | 0002 | AXX |
 |
|||||
| S9939 | 2024.07.21 | 1 | N09W17 | 0002 | AXX |
 |
|||||
| Total spot count: | 80 | 226 | 120 | ||||||||
| Sunspot number: | 200 | 426 | 270 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 138 | 278 | 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): | 220 | 234 | 216 | ||||||||
| 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 | 197.1 (1) | 125.5 (2A) / 185.3 (2B) / 205.4 (2C) | (134.7 projected, -0.2) | (5.4) | |
| 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.
