The geomagnetic field was at quiet to unsettled levels on July 4. 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 173.0 - decreasing 11.4 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 163.25. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 163.25 on January 4, 2024). The Potsdam WDC planetary A index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 8.9). Three hour interval K indices: 22112333 (planetary), ******** (Boulder), 32224435 (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 17 active regions using 2K resolution (SN: 327) and in 15 active regions using 1K resolution (SN: 230) SDO/HMI images.
Region 13727 [S18W58] decayed slowly and
quietly.
Region 13729 [S04W45] decayed slowly and produced several C flares.
ARs S9863 and S9864 were split off from the leading and trailing spot
sections of AR 13729.
Region 13731 [S17W27] was quiet and stable.
Region 13733 [N04W40] developed further and
could produce M flares. C1 flares: C1.5 @ 01:52 UT
Region 13734 [N08W03] decayed slowly and quietly.
Region 13735 [N16E09] decayed slowly and quietly.
Region 13736 [S19E51] was mostly quiet and stable.
New region 13737 [S14W75] emerged on July 1 and was numbered 3 days
later by SWPC. C1 flares: C1.7 @ 01:38 UT
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S9830 [S09W60] reemerged with a few spots.
S9838 [N25W67] reemerged with a tiny spot.
New region S9861 [N10W09] emerged before noon with tiny spots.
New region S9862 [N04E14] emerged with tiny spots before noon,
then decayed slowly.
New region S9863 [S03W35] was split off from
the trailing spot section of AR 13729. The spot group has many tiny and
small spots.
New region S9864 [S02W48] was split off from the leading spot section
of AR 13729.
New region S9865 [S08E80] rotated into view with a few spots. C1
flares: C1.6 @ 04:25 UT
New region S9866 [N27E04] was observed with tiny spots in an
old plage area.
New region S9867 [S20E25] emerged with tiny
spots.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C2.0 | 02:21 | 13734 | GOES16 | ||
| C2.6 | 06:46 | 13734 | GOES16 | simultaneous activity in AR S9865 | |
| C3.2 | 08:08 | 13729 | GOES16 | ||
| C2.2 | 09:55 | southwest limb | GOES16 | ||
| C2.5 | 10:11 | 13733 | GOES16 | ||
| C3.1 | 11:02 | S08E90 (SDO/AIA) | S9865 | GOES16 | |
| C2.2 | 11:53 | S08E90 (SDO/AIA) | S9865 | GOES16 | |
| C3.7 | 12:28 | S08E90 (SDO/AIA) | S9865 | GOES16 | |
| C4.1 | 12:38 | S08E90 (SDO/AIA) | S9865 | GOES16 | |
| C4.2 | 12:41 | S15W71 (SDO/AIA) | 13737 | GOES16 | incorrectly attributed to AR 13730 by SWPC |
| C4.5 | 13:07 | 13733 | GOES16 | ||
| M1.0 | 14:25 | S20W73 | 13723 | GOES16 | moderate type II radio sweep |
| C3.2 | 15:25 | 13737 | GOES16 | ||
| C3.9 | 16:04 | 13733 | GOES16 | ||
| C4.1 | 16:11 | S9865 | GOES16 | ||
| C3.6 | 17:47 | 13733 | GOES16 | ||
| C3.5 | 17:58 | 13737 | GOES16 | ||
| C3.0 | 18:27 | S9865 | GOES16 | ||
| C2.4 | 19:05 | 13733 | GOES16 | ||
| C2.4 | 19:40 | 13737 | GOES16 | ||
| M1.4 | 20:05 | 13730 | GOES16 | weak type II radio sweep | |
| C3.4 | 21:47 | 13737 | GOES16 | incorrectly attributed to AR 13733 by SWPC |
July 2-4: No obviously Earth directed CMEs 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 negative polarity southern hemisphere coronal hole (CH1230) could rotate into an Earth facing position on July 6-7.
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 to fair.
The geomagnetic field is expected to be quiet on July 5-8.
| 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 | ||||||||||
| 13723 | 2024.06.22 2024.06.23 |
S18W75 |
 |
location: S20W66 |
|||||||
| 13728 | 2024.06.23 2024.06.25 |
S26W66 |
 |
location: S25W53 |
|||||||
| 13727 | 2024.06.24 2024.06.25 |
2 | 2 | 2 | S18W58 | 0110 | HAX | HAX |
 |
 |
|
| S9830 | 2024.06.24 | 8 | 4 | S09W60 | 0025 | CRO |
 |
||||
| 13729 | 2024.06.25 2024.06.26 |
25 | 21 | 9 | S05W40 | 0150 | FAI | DAO |
 |
 |
area: 0130 location: S04W45 split off sections into ARs S9863 and S9864 |
| 13730 | 2024.06.26 2024.06.27 |
S18W85 |
 |
||||||||
| 13731 | 2024.06.26 2024.06.28 |
6 | 2 | S16W34 | 0010 | BXO |
 |
 |
location: S17W27 |
||
| S9838 | 2024.06.27 | 2 | 1 | S25W67 | 0003 | AXX |
 |
||||
| 13732 | 2024.06.28 | S20W68 | |||||||||
| 13733 | 2024.06.28 2024.06.29 |
8 | 23 | 14 | N05W41 | 0240 | DAI | DKI |
 |
 |
location: N04W40 area: 0420 |
| 13734 | 2024.06.28 2024.06.29 |
2 | 20 | 9 | N09W04 | 0020 | HRX | CRO |
 |
 |
location: N08W03 |
| S9843 | 2024.06.28 | N09W40 | |||||||||
| S9845 | 2024.06.28 | S30W49 | |||||||||
| 13735 | 2024.06.29 2024.06.29 |
1 | 4 | 2 | N17E09 | 0030 | HSX | HAX |
 |
 |
area: 0040 location: N16E09 |
| S9847 | 2024.06.29 | S13W20 | |||||||||
| S9849 | 2024.06.29 | S16W35 | |||||||||
| S9851 | 2024.06.30 | S40W22 | |||||||||
| S9854 | 2024.07.01 | N23W20 | |||||||||
| 13737 | 2024.07.01 2024.07.04 |
3 | 3 | 3 | S14W76 | 0100 | DSO | DAO |
 |
 |
|
| S9856 | 2024.07.01 | S28W31 | |||||||||
| 13736 | 2024.07.02 2024.07.03 |
2 | 12 | 5 | S18E54 | 0090 | DSO | DSO |
 |
 |
location: S19E51 area: 0220 |
| S9858 | 2024.07.02 | S20W00 |
 |
||||||||
| S9859 | 2024.07.03 | S27E54 |
 |
||||||||
| S9860 | 2024.07.03 | S04W23 |
 |
||||||||
| S9861 | 2024.07.04 | 7 | 4 | N10W09 | 0020 | BXO |
 |
||||
| S9862 | 2024.07.04 | 3 | N04E14 | 0005 | BXO |
 |
|||||
| S9863 | 2024.07.04 | 32 | 19 | S03W35 | 0090 | DRI |
 |
split off from AR 13729 | |||
| S9864 | 2024.07.04 | 6 | 3 | S02W48 | 0025 | CRO |
 |
split off from AR 13729 | |||
| S9865 | 2024.07.04 | 3 | 2 | S08E80 | 0060 | CAO |
 |
||||
| S9866 | 2024.07.04 | 3 | N27E04 | 0004 | BXO |
 |
|||||
| S9867 | 2024.07.04 | 2 | 1 | S20E25 | 0005 | BXO |
 |
||||
| Total spot count: | 43 | 157 | 80 | ||||||||
| Sunspot number: | 113 | 327 | 230 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 76 | 209 | 132 | (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): | 124 | 180 | 184 | ||||||||
| 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 | 124.4 (-0.9) | 8.15 |
| 2023.08 | 153.7 | 157.6 | 114.8 | 124.1 (-0.3) | 7.19 |
| 2023.09 | 154.4 | 156.0 | 134.2 | 123.9 (-0.2) | 14.26 |
| 2023.10 | 142.8 | 141.9 | 99.4 | 124.8 (+0.9) | 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 | 123.0 | (128.9 projected, -0.5) | 5.46 |
| 2024.02 | 172.5 | 168.3 | 124.7 | (129.4 projected, +0.5) | 5.31 |
| 2024.03 | 154.4 | 152.9 | 104.9 | (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) | 9.9 |
| 2024.07 | 168.7 (1) | 21.9 (2A) / 169.8 (2B) / 159.9 (2C) | (134.8 projected, -0.1) | (5.4) | |
| 2024.08 | (134.3 projected, -0.5) | ||||
| 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.
