The geomagnetic field was quiet to active on July 18 due to lingering CME effects (most likely related to the July 14 CME). Solar wind speed at SOHO ranged between 448 and 677 km/sec. The high latitude magnetometer at Andenes recorded quiet to minor storm levels.
Solar flux density measured at 17h UT on 2.8 GHz was 197.5 - increasing 21.1 over the previous solar rotation (the measurement at 20h UT was flare enhanced). (Centered 1 year average SF at 1 AU - 183 days ago: 147.56. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 14 (STAR Ap - based on the mean of three hour interval ap indices: 13.5). Three hour interval K indices: 43213142 (planetary), 43333332 (Boulder), 54223121 (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 15 active regions using 2K resolution (SN: 318) and in 12 active regions using 1K resolution (SN: 197) SDO/HMI images.
Region 13363 [S21W84] rotated partly out of
view and produced a few C flares and one M flare.
Region 13370 [S14W49] was quiet and stable.
Region 13371 [S16W28] decayed slowly and
quietly.
Region 13372 [N22W12] decayed slowly and
quietly with the last magnetic delta disappearing.
Region 13373 [N08E15] displayed signs of decay and produced several C
flares. A major flare is
still possible.
Region 13374 [S08E15] was quiet and stable.
Region 13375 [N12W64] decayed slowly and quietly.
Region 13376 [N24E28] developed further and produced two M flares.
Further M class flaring is possible, especially considering that the neutral
line has an east-west orientation and polarities may be reversed.
Region 13377 [S09E60] was mostly quiet and stable.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S8764 [N17W38] was quiet and stable.
S8767 [N19W46] decayed slowly and quietly.
S8775 [S27E61] was quiet and stable.
New region S8778 [S26E27] emerged with several spots and has
potential for further growth.
New region S8779 [N14E82] rotated partly into view with a large spot.
M flares are possible.
New region S8780 [N19E84] rotated partly into view.
New region S8781 [N15E41] was observed with tiny spots in an old
plage area.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C9.1 | 03:53 | 13373 | GOES16 | ||
| C8.9 | 04:50 | 13373 | GOES16 | ||
| C8.3 | 06:10 | N26E40 | 13376 | GOES16 | |
| M1.5 | 06:56 | S8779 | GOES16 | ||
| C4.8 | 09:06 | N08E28 | 13373 | GOES16 | |
| C3.2 | 10:46 | N08E23 | 13373 | GOES16 | |
| C3.0 | 11:48 | 13373 | GOES16 | ||
| C5.2 | 12:49 | 13363 | GOES16 | ||
| C2.6 | 13:59 | 13373 | GOES16 | ||
| C2.3 | 15:07 | 13363 | GOES16 | ||
| C5.3 | 15:41 | S8779 | GOES16 | ||
| C5.0 | 17:29 | N26E01 | 13372 | GOES16 | moderate type II and weak type IV radio sweep |
| C6.3 | 18:33 | S8779 | GOES16 | ||
| C6.0 | 19:25 | 13376 | GOES16 | incorrectly attributed to AR 13373 by SWPC | |
| M1.3 | 19:47 | 13376 | GOES16 | ||
| M1.4 | 20:05 | 13363 | GOES16 | simultaneous flare in AR S8778 | |
| M2.1 | 20:27 | 13376 | GOES16 | simultaneous flare in AR 13363 | |
| C4.9 | 22:01 | 13363 | GOES16 | ||
| C8.5 | 22:44 | 13363 | GOES16 | ||
| C3.2 | 22:58 | 13376 | GOES16 |
July 16: No obviously Earth directed CMEs were
observed.
July 17-18: An asymmetrical full halo CME was observed beginning
before the peak of a long duration M5 flare in AR 13363 at
00:06
UT on July 18. LASCO C2 observed the CME beginning at 23:36 UT on July 17. Due to the source location near the southwest limb it is
uncertain when the CME will reach Earth, the estimate is sometime
between late on July 19 and early on July 21.
[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 very poor due to proton event effects. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet to unsettled on July 19. It is uncertain when the July 17/18 CME will reach Earth, unsettled to major storm levels are likely on July 20-21. Effects from CH1161 will probably not be noticeable due to CME effects.
| 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 | ||||||||||
| 13363 | 2023.07.05 2023.07.06 |
3 | 2 | 1 | S21W86 | 0380 | HKX | CKO |
 |
 |
|
| 13370 | 2023.07.09 2023.07.10 |
1 | S15W48 | 0001 | AXX |
 |
 |
location: S14W49 |
|||
| 13371 | 2023.07.10 2023.07.11 |
1 | 2 | S15W33 | 0000 | AXX | AXX |
 |
 |
area: 0002 location: S16W28 |
|
| S8752 | 2023.07.10 | N17W53 | |||||||||
| S8753 | 2023.07.10 | S29W36 | |||||||||
| 13372 | 2023.07.11 2023.07.11 |
20 | 39 | 16 | N23W12 | 0560 | FHO | FHO |
 |
 |
beta-gamma area: 0710 |
| S8756 | 2023.07.11 | S15W54 | |||||||||
| S8758 | 2023.07.12 | N26W49 | |||||||||
| 13373 | 2023.07.13 2023.07.14 |
18 | 51 | 25 | N07E13 | 0500 | EKC | EKC |
 |
 |
beta-gamma-delta area: 0970 location: N08E15 |
| 13374 | 2023.07.13 2023.07.14 |
2 | 4 | 2 | S08E15 | 0020 | HRX | HSX |
 |
 |
area: 0040 |
| S8764 | 2023.07.13 | 5 | N17W38 | 0008 | AXX |
 |
 |
||||
| S8765 | 2023.07.13 | S00W16 | |||||||||
| S8766 | 2023.07.14 | N27W30 | |||||||||
| S8767 | 2023.07.15 | N19W59 |
 |
||||||||
| S8768 | 2023.07.15 | S24W21 | |||||||||
| 13375 | 2023.07.15 2023.07.17 |
1 | 2 | 1 | N12W65 | 0000 | AXX | CRO |
 |
 |
area: 0007 location: N12W64 |
| S8771 | 2023.07.15 | S32E21 | |||||||||
| 13376 | 2023.07.15 2023.07.17 |
15 | 33 | 15 | N24E29 | 0180 | DSO | DKO |
 |
 |
beta-gamma area: 0370 location: N24E28 |
| S8773 | 2023.07.16 | S28W51 | |||||||||
| 13377 | 2023.07.17 2023.07.17 |
2 | 8 | 4 | S09E60 | 0210 | DSO | DHO |
 |
area: 0550 |
|
| S8775 | 2023.07.17 | 3 | 2 | S27E61 | 0020 | HRX |
 |
 |
|||
| S8776 | 2023.07.17 | S06W28 |
 |
||||||||
| S8777 | 2023.07.17 | S19E15 |
 |
||||||||
| S8778 | 2023.07.18 | 12 | 7 | S26E27 | 0070 | DRI |
 |
||||
| S8779 | 2023.07.18 | 2 | 2 | N14E82 | 0450 | HHX |
 |
||||
| S8780 | 2023.07.18 | 1 | 1 | N19E84 | 0120 | HSX |
 |
||||
| S8781 | 2023.07.18 | 3 | 1 | N15E41 | 0006 | AXX |
 |
||||
| Total spot count: | 62 | 168 | 77 | ||||||||
| Sunspot number: | 142 | 318 | 197 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 105 | 247 | 156 | (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): | 156 | 175 | 158 | ||||||||
| 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 | 178.4 (1) | 84.8 (2A) / 146.1 (2B) / 169.4 (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.
