The geomagnetic field was at very quiet levels on July 18. The high latitude magnetometer at Andenes recorded quiet 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 208.7 - increasing 11.8 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 164.07. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 164.07 on January 18, 2024). The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.9). Three hour interval K indices: 11111111 (planetary), ******** (Boulder), 11112210 (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 22 active regions using 2K resolution (SN: 492) and in 21 active regions using 1K resolution (SN: 352) SDO/HMI images.
AR 13742 [S25W44] was quiet and stable.
AR 13743 [S08W56] decayed slowly and was quiet.
AR 13744 [N16W42] produced a few C flares.
AR 13745 [S21W48] decayed slowly and quietly.
AR 13748 [N15W26] was quiet and stable.
AR 13749 [S33E04] decayed slowly and quietly.
AR 13750 [S19W02] decayed slowly and quietly.
AR 13751 [S08E13] was the most active region on the visible disk due
to multiple magnetic delta structures in the central spot section.
AR 13752 [N22E16] decayed slowly and quietly losing the trailing
spots.
AR 13753 [N12W62] developed and became a compact region with a
magnetic delta configuration.
AR 13754 [N25E31] decayed slowly and quietly.
AR 13755 [N02E34] decayed slowly and quietly.
AR 13756 [S17E40] was quiet and stable.
AR 13757 [N18E48] was quiet and stable.
AR 13758 [S07W52] was mostly quiet and stable.
AR 13759 [S06W09] developed and could produce a minor M class flare.
New AR 13760 [N19W02] was first observed with spots on July 14 and
was numbered by SWPC 4 days later.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S9913 [S12W34] was quiet and stable.
S9915 [N17W56] decayed slowly and quietly.
S9916 [S16W65] decayed slowly and quietly.
New region S9921 [N17W73] emerged with tiny spots.
New region S9922 [S09E28] emerged with tiny spots.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C3.0 | 00:26 | 13751 | GOES16 | ||
| C2.6 | 01:37 | 13751 | GOES16 | ||
| C2.8 | 01:56 | 13751 | GOES16 | ||
| C3.3 | 02:18 | 13751 | GOES16 | ||
| C2.9 | 02:56 | 13751 | GOES16 | incorrectly attributed to AR 13754 by SWPC | |
| C2.6 | 03:16 | 13751 | GOES16 | ||
| C8.2/1F | 04:20 | S07E26 | 13751 | GOES16 | |
| C4.6 | 04:36 | 13744 | GOES16 | ||
| C6.7 | 05:33 | 13751 | GOES16 | ||
| C5.0 | 06:49 | N12W52 | 13753 | GOES16 | |
| C5.6 | 06:58 | 13751 | GOES16 | attributed to AR 13753 by SWPC. Simultaneous flare in AR 13760 | |
| C6.2 | 07:25 | GOES16 | |||
| C3.9 | 07:50 | 13751 | GOES16 | ||
| C3.8 | 08:29 | 13751 | GOES16 | ||
| C6.4 | 09:01 | N18W30 | 13744 | GOES16 | |
| C5.0 | 09:21 | 13751 | GOES16 | ||
| M2.2 | 10:14 | S07E24 | 13751 | GOES16 | |
| M2.0 | 10:27 | 13751 | GOES16 | ||
| M1.6 | 10:40 | 13751 | GOES16 | ||
| C3.0 | 11:42 | 13751 | GOES16 | ||
| C2.6 | 12:01 | 13751 | GOES16 | ||
| C4.5 | 12:25 | S08E22 | 13751 | GOES16 | |
| C3.0 | 12:52 | 13751 | GOES16 | ||
| C2.7 | 13:32 | 13744 | GOES16 | ||
| C2.6 | 13:48 | 13751 | GOES16 | ||
| C4.3 | 14:40 | S08E22 | 13751 | GOES16 | |
| C4.4 | 15:18 | S07E21 | 13751 | GOES16 | |
| C4.6 | 15:29 | 13751 | GOES16 | ||
| C6.2 | 15:49 | 13751 | GOES16 | ||
| C7.4 | 16:20 | N23E37 | 13754 | GOES16 | |
| C3.2 | 17:15 | S9916 | GOES16 | ||
| C2.9 | 18:14 | 13751 | GOES16 | ||
| C2.6 | 18:52 | 13751 | GOES16 | ||
| C2.6 | 20:12 | 13751 | GOES16 | ||
| C2.8 | 20:49 | 13751 | GOES16 | ||
| C3.7 | 22:39 | 13750 | GOES16 |
July 16: The M1.9 flare in AR 13744 peaking at 22:06 UT was
associated with a moderate type II radio sweep and apparently a faint
partial halo CME. Components of this CME could reach Earth on July 19-20.
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: 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 |
3 | 9 | 4 | S15W65 | 0030 | CRO | HAX |
 |
 |
location: S25W44 area: 0110 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 |
6 | 13 | 5 | S09W57 | 0040 | CRO | CRO |
 |
 |
area: 0025 location: S09W56 |
| 13745 | 2024.07.08 2024.07.10 |
6 | 22 | 7 | S20W50 | 0070 | CAO | DAI |
 |
 |
area: 0100 location: S21W48 |
| 13744 | 2024.07.09 2024.07.09 |
5 | 17 | 10 | N16W43 | 0040 | CAI | DRI |
 |
 |
area: 0050 location: N16W42 |
| 13753 | 2024.07.10 2024.07.15 |
4 | 7 | 5 | N15W62 | 0050 | CAO | DAC |
 |
 |
beta-delta location: N12W62 area: 0100 |
| 13748 | 2024.07.10 2024.07.12 |
3 | 14 | 7 | N16W24 | 0010 | BXO | CRO |
 |
 |
area: 0030 location: N15W26 |
| 13747 | 2024.07.11 | 2 | S25W45 | 0110 | HAX | AR 13747 is the trailing polarity section of AR 13742 | |||||
| 13758 | 2024.07.12 2024.07.17 |
5 | 16 | 6 | S08W50 | 0050 | CAO | DAO |
 |
 |
area: 0070 location: S07W52 |
| 13750 | 2024.07.12 2024.07.13 |
3 | 15 | 7 | S19W01 | 0020 | CRO | CRO |
 |
 |
location: S19W02 area: 0040 |
| 13749 | 2024.07.12 2024.07.13 |
1 | 5 | 3 | S33E04 | 0010 | AXX | AXX |
 |
 |
|
| 13751 | 2024.07.13 2024.07.13 |
28 | 63 | 43 | S08E14 | 0400 | EKC | EKC |
 |
 |
beta-gamma-delta location: S08E13 area: 0600 |
| 13752 | 2024.07.13 2024.07.14 |
2 | 3 | 1 | N22E14 | 0010 | HRX | HRX |
 |
 |
area: 0030 location: N22E16 |
| S9901 | 2024.07.13 | N35W43 | |||||||||
| 13754 | 2024.07.14 | 4 | 7 | 3 | N25E30 | 0040 | CAO | CRO |
 |
 |
location: N25E31 |
| 13760 | 2024.07.14 2024.07.18 |
2 | 4 | 3 | N20W05 | 0020 | CRO | CRO |
 |
 |
location: N19W02 |
| S9905 | 2024.07.14 | S35W13 | |||||||||
| S9907 | 2024.07.15 | N22E29 |
 |
||||||||
| 13755 | 2024.07.15 2024.07.16 |
8 | 17 | 8 | N02E35 | 0080 | CAO | DAO |
 |
 |
location: N02E34 |
| 13756 | 2024.07.15 2024.07.16 |
1 | 6 | 3 | S17E40 | 0100 | HSX | CSO |
 |
 |
area: 0160 |
| S9910 | 2024.07.15 | S29W37 | |||||||||
| 13757 | 2024.07.15 2024.07.16 |
1 | 8 | 3 | N18E47 | 0040 | HSX | CSO |
 |
 |
area: 0060 |
| S9913 | 2024.07.15 | 4 | S12W34 | 0007 | AXX |
 |
 |
||||
| 13759 | 2024.07.15 2024.07.17 |
12 | 24 | 15 | S06W10 | 0110 | DAO | DAI |
 |
 |
location: S06W09 area: 0230 |
| S9915 | 2024.07.16 | 1 | 1 | N17W56 | 0005 | AXX |
 |
 |
|||
| S9916 | 2024.07.16 | 3 | 1 | S16W65 | 0015 | CRO |
 |
 |
SWPC includes these spots in AR 13742 | ||
| S9917 | 2024.07.16 | N19E24 |
 |
||||||||
| S9918 | 2024.07.16 | N06W00 |
 |
||||||||
| S9920 | 2024.07.17 | N14W01 |
 |
||||||||
| S9921 | 2024.07.18 | 3 | 1 | N19W73 | 0005 | BXO |
 |
||||
| S9922 | 2024.07.18 | 11 | 6 | S09E28 | 0040 | DRO |
 |
||||
| Total spot count: | 96 | 272 | 142 | ||||||||
| Sunspot number: | 276 | 492 | 352 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 171 | 349 | 219 | (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): | 304 | 271 | 282 | ||||||||
| 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 | 196.3 (1) | 103.6 (2A) / 178.4 (2B) / 196.3 (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.
