The geomagnetic field was quiet to active on July 20. Solar wind speed at SOHO ranged between 363 and 564 km/sec. The high latitude magnetometer at Andenes recorded quiet to unsettled levels. A solar wind shock was observed at ACE at 16:08 UT, the likely arrival of the July 17 CME.
Solar flux density measured at 20h UT on 2.8 GHz was 184.3 - increasing 14.7 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 147.82. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 9.3). Three hour interval K indices: 11101442 (planetary), 11123433 (Boulder), 11113333 (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: 278) and in 9 active regions using 1K resolution (SN: 175) SDO/HMI images.
Region 13372 [N22W39] decayed slowly and was
mostly quiet. C1 flares: C1.9 @ 21:35 UT
Region 13373 [N08W12] developed slowly and has 2 magnetic delta
structures in the intermediate spot section. An M class flare is possible.
C1 flares: C1.7 @ 08:38, C1.7 @ 11:18, C1.6 @ 15:40 UT
Region 13374 [S09W09] decayed slowly and quietly.
Region 13376 [N23E02] decayed slowly and was
mostly quiet. C1 flares: C1.6 @ 15:53, C1.7 @ 20:31 UT
Region 13377 [S09E34] was mostly quiet and stable. C1 flares: C1.4 @
11:52, C1.6 @ 14:51 UT
Region 13378 [S27W00] was quiet and stable.
Region 13379 [N15E58] was mostly quiet and stable.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S8775 [S27E38] was quiet and stable.
S8781 [N15E17] was mostly quiet and stable. C1 flares: C1.5 @ 19:05
UT
New region S8784 [S42E61] emerged with a few tiny spots at a high
latitude.
New region S8785 [S18W30] emerged with a tiny spot.
AR 13363 behind the southwest limb produced a C1.6 flare at 10:03 and a C1.9 flare at 10:28 UT
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C2.2 | 06:04 | 13377 | GOES16 | ||
| C9.7 | 19:49 | 13373 | GOES16 | simultaneous flare in AR 13376 | |
| C2.2 | 23:51 | 13379 | GOES16 |
July 19-20: 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 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 21 due to CME effects. Weak effects from CH1161 are possible on April 22-23.
| 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 | ||||||||||
| 13370 | 2023.07.09 2023.07.10 |
S15W76 | |||||||||
| 13371 | 2023.07.10 2023.07.11 |
S15W53 |
 |
location: S15W49 |
|||||||
| 13372 | 2023.07.11 2023.07.11 |
13 | 33 | 17 | N23W37 | 0380 | FKO | FHO |
 |
 |
area: 0540 location: N22W39 |
| 13373 | 2023.07.13 2023.07.14 |
21 | 39 | 24 | N08W15 | 0520 | EKC | EKC |
 |
 |
beta-delta area: 0880 location: N08W12 |
| 13374 | 2023.07.13 2023.07.14 |
1 | 5 | S08W12 | 0010 | AXX | BXO |
 |
 |
area: 0015 | |
| S8765 | 2023.07.13 | S00W42 | |||||||||
| S8766 | 2023.07.14 | N27W56 | |||||||||
| S8768 | 2023.07.15 | S24W47 | |||||||||
| S8771 | 2023.07.15 | S32W05 | |||||||||
| 13376 | 2023.07.15 2023.07.17 |
8 | 25 | 12 | N25E03 | 0130 | DSO | CSO |
 |
 |
area: 0230 location: N23E02 |
| 13377 | 2023.07.17 2023.07.17 |
5 | 12 | 6 | S09E34 | 0240 | DSO | DHO |
 |
 |
area: 0600 |
| S8775 | 2023.07.17 | 6 | 1 | S27E38 | 0008 | BXO |
 |
 |
|||
| S8776 | 2023.07.17 | S06W54 | |||||||||
| S8777 | 2023.07.17 | S19W11 | |||||||||
| 13378 | 2023.07.18 2023.07.19 |
7 | 24 | 13 | S26W01 | 0030 | CRO | DRI |
 |
 |
area: 0100 |
| 13379 | 2023.07.18 2023.07.19 |
6 | 14 | 9 | N16E63 | 0260 | FHO | FHI |
 |
 |
area: 0550 location: N15E58 |
| S8780 | 2023.07.18 | N19E58 |
 |
included in AR 13379 | |||||||
| S8781 | 2023.07.18 | 6 | 2 | N15E17 | 0010 | BXO |
 |
 |
|||
| S8782 | 2023.07.19 | N12E20 |
 |
||||||||
| S8783 | 2023.07.19 | S25W15 |
 |
||||||||
| S8784 | 2023.07.20 | 3 | 1 | S42E61 | 0010 | BXO |
 |
||||
| S8785 | 2023.07.20 | 1 | S18W30 | 0002 | AXX |
 |
|||||
| Total spot count: | 61 | 168 | 85 | ||||||||
| Sunspot number: | 131 | 278 | 175 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 104 | 216 | 133 | (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): | 144 | 153 | 140 | ||||||||
| 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 | 179.2 (1) | 93.6 (2A) / 145.1 (2B) / 166.0 (2C) | (135.4 projected, -0.5) | (8.0) | |
| 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.
