The geomagnetic field was quiet to active on July 21 due to CME influences. Solar wind speed at SOHO ranged between 361 and 423 km/sec. The high latitude magnetometer at Andenes recorded quiet to major storm levels. A solar wind shock was observed at ACE at 16:08 UT, the likely arrival of the July 17 CME. A transient was observed arriving at DSCOVR at 19:24 UT, probably related to a CME observed on July 18.
Solar flux density measured at 20h UT on 2.8 GHz was 172.8 - increasing 12.0 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 147.98. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 11.8). Three hour interval K indices: 33211224 (planetary), 34222334 (Boulder), 45122326 (Andenes).
The background x-ray flux was at the class C1 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 11 active regions using 2K resolution (SN: 257) and in 8 active regions using 1K resolution (SN: 154) SDO/HMI images.
Region 13372 [N22W52] decayed slowly and
produced a few low level C flares. The region was the source of an M3.1
flare at 03:36 UT on July 22. C1 flares: C1.4 @ 04:20, C1.8 @ 23:21 UT
Region 13373 [N07W25] decayed slowly in the intermediate spot
section. The region was the source of an M1.0 flare at 04:16 on July 22.
C1.4 flares: C1.4 @ 04:41, C1.4 @ 08:14, C1.7 @ 22:29, C1.7 @ 22:52 UT
Region 13376 [N22W11] was quiet and stable.
Region 13377 [S09E20] was quiet and stable.
Region 13378 [S27W15] decayed slowly and was mostly quiet. C1 flares:
C1.5 @ 07:40, C1.5 @ 09:52 UT
Region 13379 [N15E44] was mostly unchanged and quiet. C1 flares: C1.9
@ 05:47 UT
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S8775 [S25E18] was quiet and stable.
S8781 [N14E04] was quiet and stable.
S8784 [S43E51] was quiet and stable.
New region S8786 [N10E18] emerged with a tiny spot.
New region S8787 [N07W64] emerged with a tiny spot.
A C1.4 flare at 20:13 UT had its origin behind the southeast limb.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C2.2 | 00:30 | 13373 | GOES16 | ||
| C2.1 | 10:54 | N05W19 | 13373 | GOES16 |
July 19-21: No obviously Earth directed CMEs were
observed.
July 22: A CME was associated with an M1.0 flare in AR 13373 early in
the day. It is not yet certain if this CME has any Earth directed
components.
[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 southern hemisphere coronal hole (CH1161) was in an Earth facing position on July 18.
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 to unsettled on July 22 due to CME effects. Weak effects from CH1161 are possible on April 23. Quiet conditions are likely on July 24.
| Coronal holes (1) | Coronal mass ejection (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 | ||||||||||
| 13371 | 2023.07.10 2023.07.11 |
S15W67 |
location: S15W62 |
||||||||
| 13372 | 2023.07.11 2023.07.11 |
9 | 20 | 14 | N23W51 | 0340 | EKO | FKO |
 |
 |
area: 0520 location: N22W52 |
| 13373 | 2023.07.13 2023.07.14 |
22 | 43 | 26 | N08W30 | 0550 | EKC | FKC |
 |
 |
beta-delta area: 0720 location: N07W25 |
| 13374 | 2023.07.13 2023.07.14 |
S08W26 |
 |
||||||||
| S8765 | 2023.07.13 | S00W55 | |||||||||
| S8771 | 2023.07.15 | S32W18 | |||||||||
| 13376 | 2023.07.15 2023.07.17 |
9 | 17 | 5 | N25W11 | 0100 | CSO | CSO |
 |
 |
area: 0180 location: N22W11 |
| 13377 | 2023.07.17 2023.07.17 |
5 | 11 | 6 | S09E20 | 0210 | DSO | DHO |
 |
 |
area: 0570 |
| S8775 | 2023.07.17 | 11 | S25E18 | 0015 | BXO |
 |
 |
||||
| S8777 | 2023.07.17 | S19W24 | |||||||||
| 13378 | 2023.07.18 2023.07.19 |
8 | 18 | 10 | S26W14 | 0030 | CRO | CSO |
 |
 |
area: 0090 |
| 13379 | 2023.07.18 2023.07.19 |
8 | 14 | 10 | N16E48 | 0270 | FHO | FHI |
 |
 |
area: 0530 location: N15E44 |
| S8780 | 2023.07.18 | N19E46 | included in AR 13379 | ||||||||
| S8781 | 2023.07.18 | 9 | 2 | N14E04 | 0020 | BXO |
 |
 |
|||
| S8782 | 2023.07.19 | N12E07 | |||||||||
| S8783 | 2023.07.19 | S25W38 | |||||||||
| S8784 | 2023.07.20 | 2 | 1 | S43E51 | 0010 | CRO |
 |
 |
|||
| S8785 | 2023.07.20 | S18W43 |
 |
||||||||
| S8786 | 2023.07.21 | 1 | N10E18 | 0002 | AXX |
 |
|||||
| S8787 | 2023.07.21 | 1 | N07W64 | 0001 | AXX |
 |
|||||
| Total spot count: | 61 | 147 | 74 | ||||||||
| Sunspot number: | 121 | 257 | 154 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 104 | 200 | 127 | (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): | 133 | 141 | 123 | ||||||||
| 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 |
| 2021.12 | 103.0 | 99.8 | 67.5 | 55.9 (+5.1) | 6.40 |
| 2022.01 | 103.8 | 100.5 | 55.3 | 60.1 (+4.2) | 8.92 |
| 2022.02 | 109.1 | 106.5 | 60.9 | 64.7 (+4.6) | 10.46 |
| 2022.03 | 117.0 | 115.8 | 78.6 | 68.7 (+4.0) | 10.20 |
| 2022.04 | 130.8 | 131.7 | 84.0 | 73.0 (+4.3) | 11.79 |
| 2022.05 | 133.8 | 136.8 | 96.5 | 77.4 (+4.4) | 7.48 |
| 2022.06 | 116.1 | 119.8 | 70.3 | 81.1 (+3.7) | 8.20 |
| 2022.07 | 125.4 | 129.5 | 91.4 | 86.7 (+5.6) | 9.51 |
| 2022.08 | 114.2 | 117.1 | 74.6 | 92.5 (+5.8) | 10.92 |
| 2022.09 | 135.1 | 136.5 | 96.0 | 96.4 (+3.9) | 12.18 |
| 2022.10 | 133.5 | 132.7 | 95.5 | 98.7 (+2.3) | 11.16 |
| 2022.11 | 123.4 | 120.7 | 80.5 | 101.0 (+2.3) | 9.33 |
| 2022.12 | 147.9 | 143.4 | 112.8 | 106.6 (+5.6) | 10.99 |
| 2023.01 | 182.4 | 176.6 | 143.6 | (113.7 projected, +6.1) | 8.73 |
| 2023.02 | 167.2 | 163.2 | 110.9 | (118.5 projected, +4.8) | 14.48 (current SC25 peak) |
| 2023.03 | 157.2 | 155.6 | 122.6 | (121.6 projected, +3.1) | 14.42 |
| 2023.04 | 145.4 | 146.4 | 96.4 | (127.0 projected, +5.4) | 13.40 |
| 2023.05 | 155.6 | 159.2 | 137.9 | (132.7 projected, +5.7) | 10.67 |
| 2023.06 | 161.7 | 166.8 | 163.4 | (135.9 projected, +3.2) | 8.95 |
| 2023.07 | 178.9 (1) | 97.5 (2A) / 144.0 (2B) / 162.6 (2C) | (135.4 projected, -0.5) | (8.2) | |
| 2023.08 | (136.4 projected, +1.0) | ||||
| 2023.09 | (139.8 projected, +3.4) | ||||
| 2023.10 | (141.6 projected, +1.8) | ||||
| 2023.11 | (144.2 projected max SC25, +2.6) | ||||
| 2023.12 | (143.4 projected, -0.1) | ||||
| 2024.01 | (140.1 projected, -3.3) | ||||
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
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.
