The geomagnetic field was at very quiet levels on July 19. 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 201.6 - increasing 5.9 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 164.12. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 164.12 on January 19, 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: 01111111 (planetary), ******** (Boulder), 23112132 (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 25 active regions using 2K resolution (SN: 506) and in 22 active regions using 1K resolution (SN: 345) SDO/HMI images.
AR 13742 [S25W57] decayed
slowly and quietly.
AR 13743 [S11W77] decayed slowly and was mostly quiet.
AR 13744 [N16W56] decayed slowly and quietly.
AR 13745 [S22W60] decayed slowly and was mostly quiet.
AR 13748 [N16W38] decayed slowly and quietly.
AR 13749 [S30W16] decayed slowly and quietly.
AR 13750 [S20W18] decayed slowly and quietly.
AR 13751 [S08W00] produced C and M flares, however, slow decay was
observed in most parts of the spot group
AR 13752 [N22E02] was quiet and stable.
AR 13753 [N12W76] decayed significantly and lost the magnetic delta
configuration after producing the largest flare of the day
AR 13754 [N25E18] gained a few spots and was mostly quiet.
AR 13755 [N02E22] decayed slowly and quietly.
AR 13756 [S17E27] was mostly quiet and stable.
AR 13757 [N18E35] was quiet and stable.
AR 13758 [S07W67] decayed and produced an M flare towards the end of
the day.
AR 13759 [S06W24] gained area and was mostly quiet.
AR 13760 [N20W17] was quiet and stable.
New AR 13761 [S09E14] emerged on July 18 and was numbered by SWPC the
next day.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
New region S9923 [S20W02] emerged with tiny spots.
New region S9924 [S24W12] emerged with tiny spots.
New region S9925 [S12E68] rotated into view with tiny spots.
New region S9926 [S12E80] rotated into view.
New region S9927 [N10E57] emerged with tiny spots.
New region S9928 [S04E38] was observed with tiny spots in an
old plage area.
New region S9929 [S35E01] emerged with a tiny spot.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C2.6 | 04:20 | 13759 | GOES16 | ||
| C2.7 | 04:43 | 13751 | GOES16 | ||
| C2.4 | 05:02 | 13751 | GOES16 | ||
| C5.0 | 05:29 | N07W64 | 13753 | GOES16 | |
| C6.5 | 05:38 | 13753 | GOES16 | ||
| C2.8 | 07:23 | GOES16 | |||
| C6.5 | 08:01 | S11E08 | 13751 | GOES16 | |
| M3.2/1F | 08:23 | N11W67 | 13753 | GOES16 | |
| C2.8 | 09:25 | 13761 | GOES16 | ||
| C2.3 | 09:47 | 13751 | GOES16 | ||
| C2.4 | 10:24 | southeast limb | S9926 | GOES16 | |
| C3.0 | 10:50 | southeast limb | S9926 | GOES16 | |
| C6.2 | 12:01 | S19W58 | 13745 | GOES16 | |
| C4.8 | 12:34 | S9916 | GOES16 | ||
| C3.2 | 13:50 | 13751 | GOES16 | ||
| C8.7/1N | 14:01 | S12E08 | 13751 | GOES16 | |
| C7.5 | 14:08 | 13756 | GOES16 | ||
| C2.7 | 15:54 | S09E06 | 13751 | GOES16 | |
| C2.7 | 16:12 | 13751 | GOES16 | ||
| C2.0 | 16:48 | 13751 | GOES16 | ||
| M2.0/2N | 18:06 | S10E03 | 13751 | GOES16 | |
| C2.7 | 19:56 | 13751 | GOES16 | ||
| C8.7 | 22:37 | S05W68 | 13758 | GOES16 | |
| M1.0 | 22:51 | 13758 | GOES16 | ||
| C9.9 | 22:59 | 13758 | GOES16 | ||
| C4.2 | 23:48 | 13758 | GOES16 |
July 17: Type II and IV radio sweeps hint at the possibility of CMEs
after M5 and M3 flares in ARs 13743 and 13758. Any effects from these could
reach Earth on July 20-21.
July 18-19: 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]
A large recurrent negative polarity coronal hole (CH1232) in the northern hemisphere rotated across the central meridian on July 14-17.
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 to active on July 19-21 due to coronal hole and 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 | ||||||||||
| 13742 | 2024.07.07 2024.07.09 |
1 | 6 | 2 | S16W80 | 0010 | AXX | HAX |
 |
 |
location: S25W57 area: 0100 SWPC split off the trailing spot section into AR 13747 on 2024.07.11 On 2024.07.17 SWPC began including the spots of AR S9916 in this AR |
| 13743 | 2024.07.08 2024.07.09 |
2 | 1 | 1 | S11W72 | 0010 | BXO | AXX |
 |
 |
area: 0003 location: S11W77 |
| 13745 | 2024.07.08 2024.07.10 |
6 | 9 | 5 | S23W61 | 0020 | CRO | BXO |
 |
 |
area: 0040 location: S22W60 |
| 13744 | 2024.07.09 2024.07.09 |
4 | 14 | 7 | N16W55 | 0020 | CRO | DRI |
 |
 |
area: 0050 location: N16W56 |
| 13753 | 2024.07.10 2024.07.15 |
4 | 5 | 2 | N12W76 | 0080 | CAO | CRO |
 |
 |
area: 0020 |
| 13748 | 2024.07.10 2024.07.12 |
2 | 11 | 4 | N15W40 | 0010 | AXX | BXO |
 |
 |
area: 0020 location: N16W38 |
| 13747 | 2024.07.11 | 2 | S25W59 | 0060 | HAX | AR 13747 is the trailing polarity section of AR 13742 | |||||
| 13758 | 2024.07.12 2024.07.17 |
2 | 5 | 1 | S07W68 | 0010 | CRO | CRO |
 |
 |
location: S07W67 |
| 13750 | 2024.07.12 2024.07.13 |
1 | 9 | 4 | S20W21 | 0010 | AXX | CRO |
 |
 |
location: S20W18 area: 0020 |
| 13749 | 2024.07.12 2024.07.13 |
4 | S33W10 | 0005 | BXO |
 |
 |
location: S30W16 | |||
| 13751 | 2024.07.13 2024.07.13 |
32 | 68 | 40 | S08E01 | 0410 | EKC | EAC |
 |
 |
beta-gamma-delta location: S08W00 area: 0510 |
| 13752 | 2024.07.13 2024.07.14 |
1 | 4 | 2 | N22E01 | 0010 | HRX | HRX |
 |
 |
area: 0020 location: N22E02 |
| S9901 | 2024.07.13 | N35W56 | |||||||||
| 13754 | 2024.07.14 | 3 | 12 | 6 | N24E17 | 0010 | CRO | CRI |
 |
 |
location: N25E18 area: 0040 |
| 13760 | 2024.07.14 2024.07.18 |
1 | 7 | 3 | N18W17 | 0010 | AXX | DRO |
 |
 |
location: N20W17 area: 0030 |
| S9905 | 2024.07.14 | S35W26 | |||||||||
| S9907 | 2024.07.15 | N22E16 | |||||||||
| 13755 | 2024.07.15 2024.07.16 |
8 | 22 | 11 | N02E19 | 0050 | CAO | CRI |
 |
 |
location: N02E22 |
| 13756 | 2024.07.15 2024.07.16 |
2 | 5 | 2 | S26E25 | 0090 | CSO | CSO |
 |
 |
area: 0170 location: S17E27 SWPC location is probably a typo |
| S9910 | 2024.07.15 | S29W50 | |||||||||
| 13757 | 2024.07.15 2024.07.16 |
3 | 11 | 4 | N17E33 | 0020 | CSO | CAO |
 |
 |
area: 0060 |
| S9913 | 2024.07.15 | S12W47 |
 |
||||||||
| 13759 | 2024.07.15 2024.07.17 |
12 | 24 | 12 | S07W23 | 0110 | DAO | DSO |
 |
 |
location: S06W24 area: 0410 |
| S9916 | 2024.07.16 | S16W78 |
 |
SWPC includes these spots in AR 13742 | |||||||
| S9917 | 2024.07.16 | N19E11 | |||||||||
| S9918 | 2024.07.16 | N06W13 | |||||||||
| S9920 | 2024.07.17 | N14W14 | |||||||||
| 13761 | 2024.07.18 2024.07.19 |
3 | 19 | 12 | S10E13 | 0100 | DAI | DAO |
 |
 |
location: S09E14 area: 0240 |
| S9923 | 2024.07.19 | 3 | 2 | S20W03 | 0010 | BXO |
 |
||||
| S9924 | 2024.07.19 | 3 | 1 | S24W12 | 0005 | AXX |
 |
||||
| S9925 | 2024.07.19 | 3 | 1 | S12E68 | 0006 | BXO |
 |
||||
| S9926 | 2024.07.19 | 4 | 2 | S12E80 | 0100 | CAO |
 |
||||
| S9927 | 2024.07.19 | 2 | 1 | N10E57 | 0004 | BXO |
 |
||||
| S9928 | 2024.07.19 | 4 | S04E38 | 0007 | BXO |
 |
|||||
| S9929 | 2024.07.19 | 1 | S35E01 | 0001 | AXX |
 |
|||||
| Total spot count: | 89 | 256 | 125 | ||||||||
| Sunspot number: | 269 | 506 | 345 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 146 | 315 | 184 | (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): | 296 | 284 | 276 | ||||||||
| 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 | 196.5 (1) | 112.3 (2A) / 183.2 (2B) / 200.7 (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.
