The geomagnetic field was at quiet to active levels on July 27 due to a weakening high speed coronal hole stream. The high latitude magnetometer at Andenes recorded unsettled 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 17h UT on 2.8 GHz was 181.1 - increasing 7.3 over the previous solar rotation. The measurement at 20h UT was flare enhanced. (Centered 1 year average SF at 1 AU - 183 days ago: 164.43. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 164.43 on January 27, 2024). The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.3). Three hour interval K indices: 12234312 (planetary), ******** (Boulder), 43335433 (Andenes).
The background x-ray flux is at the class C3 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 18 active regions using 2K resolution (SN: 475) and in 16 active regions using 1K resolution (SN: 304) SDO/HMI images.
AR 13756 [S17W79] was quiet and stable.
AR 13757 [N18W74] decayed slowly and quietly.
AR 13762 [S13W21] decayed slowly and quietly.
AR 13763 [N04E06] gained a few tiny spots and was quiet.
AR 13764 [S03E09] was quiet and stable.
AR 13765 [S11E20] developed further and could produce M flares.
AR 13766 [S07E14] developed quickly and could produce further major
flares. A major M9.9 flare was recorded at 01:57 UT on July 28.
AR 13767 [S09E28] developed slowly and has M class flare potential.
AR 13768 [S16W12] developed significantly and could produce M flares.
AR 13769 [N22E63] was quiet and stable.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S9925 [S11W35] developed further with a moderately strong magnetic
delta configuration forming in the leading spot section. A major flare is
possible.
S9941 [N31W35] was quiet and stable.
S9948 [N29E05] decayed slowly and quietly.
S9953 [S24E04] was quiet and stable.
S9958 [N01W16] moved into the northern hemisphere and decayed slowly.
S9959 [S05E02] was quiet and stable.
S9963 [N08E28] was quiet and stable.
New region S9965 [N08E23] emerged with tiny spots.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C2.3 | 00:18 | N27W68 (SDO/AIA) | GOES16 | ||
| C4.9 | 00:47 | S12E38 (SDO/AIA) | 13767 | GOES16 | attributed to AR 13765 by SWPC |
| M4.2/1N | 02:37 | S09E24 | 13766 | GOES16 | |
| C7.0 | 03:33 | 13766 | GOES16 | ||
| M1.0 | 05:28 | 13765 | GOES16 | ||
| M3.1 | 05:46 | S11W24 (SDO/AIA) | S9925 | GOES16 | LDE, full halo CME, moderate type II radio sweep, SWPC reports location S11W30 |
| M1.5 | 06:31 | S10E32 (SDO/AIA) | 13765 | GOES16 | |
| C5.7 | 07:27 | 13765? | GOES16 | ||
| C4.3 | 07:55 | S9925 | GOES16 | ||
| C6.2 | 08:27 | S12E33 (SDO/AIA) | 13767 | GOES16 | simultaneous flare in AR S9925 at location S12W28 |
| C5.3 | 09:57 | S9925 | GOES16 | ||
| M2.0/1F | 10:40 | S09E40 | 13767 | GOES16 | |
| M1.8 | 10:54 | S9925 | GOES16 | ||
| C3.1 | 12:39 | 13765 | GOES16 | ||
| C3.5 | 12:52 | 13765 | GOES16 | ||
| C3.3 | 13:11 | 13765 | GOES16 | ||
| C2.4 | 14:47 | 13765 | GOES16 | ||
| C2.2 | 15:34 | 13767 | GOES16 | ||
| C2.5 | 16:41 | S9925 | GOES16 | ||
| M2.7/2B | 18:06 | S06E17 (SDO/AIA) | 13765/13764 | GOES16 | SWPC reports location S05E17 simultaneous flares in AR S9925 at S12W32 and in AR 13767 at S09E32 |
| M3.4 | 18:39 | S9925 | GOES16 | ||
| M1.1 | 19:38 | 13765+S9925 | GOES16 | ||
| C3.8/1F | 23:06 | S07E30 | 13767 | GOES16 | |
| C3.5 | 23:36 | 13765 | GOES16 |
July 28: A full halo CME was observed after an M9.9 flare in AR 13766
peaking at 01:57 UT. This CME will most likely reach Earth on July 30 and
cause unsettled to severe storm conditions.
July 27: A full halo CME was observed after an M3.1 flare in AR S9925
peaking at 05:46 UT. The CME could reach Earth on July 29 and cause
unsettled to major storm conditions.
July 26: 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 unsettled on July 28 and unsettled to severe storm on July 29-31 due to 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 | ||||||||||
| 13756 | 2024.07.15 2024.07.16 |
1 | 1 | 1 | S18W80 | 0080 | HSX | HSX |
 |
 |
area: 0090 location: S17W79 |
| 13757 | 2024.07.15 2024.07.16 |
1 | 1 | 1 | N18W74 | 0010 | AXX | AXX |
 |
 |
area: 0005 |
| S9925 | 2024.07.19 | 71 | 34 | S11W35 | 0580 | EKC |
 |
 |
beta-gamma-delta (including former leading spot section of AR 13762) |
||
| 13762 | 2024.07.19 | 31 | 12 | 5 | S12W30 | 0330 | FKC | BXO |
 |
 |
area: 0020 location: S13W21 SWPC includes AR S9925 in this AR |
| S9927 | 2024.07.19 | N10W47 | |||||||||
| S9931 | 2024.07.20 | N19W29 |
 |
||||||||
| 13763 | 2024.07.21 2024.07.22 |
3 | 18 | 8 | N03E08 | 0160 | CSO | DSO |
 |
 |
location: N04E06 area: 0220 |
| S9936 | 2024.07.21 | N22W00 | |||||||||
| S9937 | 2024.07.21 | N28W20 | |||||||||
| 13764 | 2024.07.22 2024.07.22 |
3 | 13 | 6 | S03E08 | 0090 | HSX | DSO |
 |
 |
area: 0190 |
| S9941 | 2024.07.22 | 6 | N31W35 | 0010 | AXX |
 |
 |
||||
| S9942 | 2024.07.22 | N08W51 | |||||||||
| S9944 | 2024.07.22 | S03W57 | |||||||||
| 13765 | 2024.07.23 2024.07.23 |
11 | 30 | 18 | S12E20 | 0180 | DSO | DKC |
 |
 |
area: 0410 location: S11E20 |
| S9948 | 2024.07.23 | 3 | N29E05 | 0004 | AXX |
 |
 |
||||
| S9950 | 2024.07.23 | N20W33 | |||||||||
| S9951 | 2024.07.23 | N13W19 | |||||||||
| S9952 | 2024.07.23 | S28W28 | |||||||||
| S9953 | 2024.07.23 | 15 | 4 | S24W04 | 0025 | BXO |
 |
 |
|||
| S9954 | 2024.07.23 | S02W39 | |||||||||
| 13766 | 2024.07.24 | 11 | 53 | 31 | S07E19 | 0130 | DSO | DAC |
 |
 |
beta-gamma-delta location: S07E14 area: 0250 |
| 13767 | 2024.07.25 | 10 | 31 | 18 | S10E30 | 0220 | DSO | EAI |
 |
 |
beta-gamma area: 0240 location: S09E28 |
| 13768 | 2024.07.25 2024.07.26 |
6 | 21 | 11 | S17W16 | 0020 | BXO | DAC |
 |
 |
location: S16W12 area: 0200 |
| S9958 | 2024.07.25 | 2 | 1 | N01W16 | 0004 | BXO |
 |
 |
|||
| S9959 | 2024.07.25 | 5 | 1 | S05W02 | 0010 | BXO |
 |
 |
|||
| S9960 | 2024.07.25 | N24W05 |
 |
||||||||
| 13769 | 2024.07.25 2024.07.26 |
1 | 1 | 1 | N23E60 | 0100 | HSX | HSX |
 |
 |
location: N22E63 area: 0200 |
| S9962 | 2024.07.25 | N24W41 | |||||||||
| S9963 | 2024.07.26 | 4 | 1 | N08E28 | 0007 | BXO |
 |
 |
|||
| S9965 | 2024.07.27 | 8 | 3 | N08E23 | 0025 | CRO |
 |
||||
| Total spot count: | 78 | 295 | 144 | ||||||||
| Sunspot number: | 178 | 475 | 304 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 123 | 353 | 202 | (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): | 196 | 261 | 243 | ||||||||
| 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 | 192.9 (1) | 158.7 (2A) / 182.3 (2B) / 216.9 (2C) | (134.7 projected, -0.2) | (6.3) | |
| 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.
