The geomagnetic field was at quiet to minor storm levels on July 26 under the influence of CME effects. Solar wind speed at DSCOVR ranged between 459 and 587 km/sec. The high latitude magnetometer at Andenes recorded unsettled to major storm levels.
Solar flux density measured at 20h UT on 2.8 GHz was 167.4 - increasing 5.2 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 148.87. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 19 (STAR Ap - based on the mean of three hour interval ap indices: 18.9). Three hour interval K indices: 35443222 (planetary), 45443323 (Boulder), 56643353 (Andenes).
The background x-ray flux was at the class C2 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 11 active regions using 2K resolution (SN: 220) and in 11 active regions using 1K resolution (SN: 161) SDO/HMI images.
Region 13376 [N22W76] was unstable as it
rotated to the northwest limb producing many C and M flares.
Region 13377 [S08W46] was quiet. The two main spots seem to have
halted the possible merge.
Region 13378 [S27W80] decayed slowly and quietly.
Region 13379 [N13W21] was mostly quiet and displayed no major changes.
Region 13380 [S11E28] decayed slowly and produced a few C flares.
Region 13384 [S16E42] was quiet and gained a few tiny spots.
New region 13385 [S16W20] emerged on July 25 and was numbered the
next day by SWPC.
New region 13386 [N12E60] emerged near the northeast limb on July 25
with SWPC numbering the spot group the following day as several spots
emerged.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
New region S8801 [N19E81] rotated into view and
may have M class flare potential.
New region S8802 [S22E77] rotated into view with small and tiny
spots.
New region S8803 [N28W07] emerged near the northeast limb with tiny
spots.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C5.5/1F | 00:40 | 13384 | GOES16 | incorrectly attributed to smaller, simultaneous flare in AR 13376 by SWPC | |
| C4.9 | 00:59 | 13376 | GOES16 | ||
| C2.3 | 02:48 | 13384 | GOES16 | ||
| C2.3 | 03:09 | 13376 | GOES16 | ||
| C9.2 | 04:11 | 13376 | GOES16 | ||
| M1.2 | 04:28 | 13376 | GOES16 | ||
| C9.1/2F | 05:17 | S08E38 | 13380 | GOES16 | simultaneous flare in AR 13376 |
| C5.2 | 06:10 | N21W67 | 13376 | GOES16 | |
| C5.6 | 06:46 | 13380 | GOES16 | ||
| C3.4 | 08:21 | 13380 | GOES16 | ||
| C8.3 | 08:44 | 13380 | GOES16 | simultaneous flare in AR 13378 | |
| C4.1 | 09:25 | northeast limb | S8801 | GOES16 | simultaneous flare in AR 13380 |
| C4.2 | 10:26 | 13376 | GOES16 | ||
| M4.6 | 10:37 | 13376 | GOES16 | ||
| C4.5 | 12:32 | 13376 | GOES16 | ||
| C4.4 | 13:12 | northeast limb | S8801 | GOES16 | |
| C7.9/1N | 15:24 | S10E31 | 13380 | GOES16 | |
| C4.7 | 15:39 | 13376 | GOES16 | ||
| M2.0 | 15:59 | 13376 | GOES16 | ||
| M1.1 | 16:13 | 13376 | GOES16 | ||
| C3.7 | 17:12 | 13376 | GOES16 | ||
| C2.8 | 17:49 | 13376 | GOES16 | simultaneous flare in AR S8802 | |
| C3.1 | 18:52 | 13376 | GOES16 | ||
| C3.4 | 19:00 | 13379 | GOES16 | ||
| C2.1 | 19:54 | S8802 | GOES16 | ||
| C3.8 | 21:54 | S8802 | GOES16 | ||
| C2.7 | 22:32 | 13376 | GOES16 | ||
| C9.2 | 23:01 | 13376 | GOES16 |
July 24-26: 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]
No obvious coronal holes are currently in or near Earth facing positions.
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 at quiet to unsettled on July 27 due to weak CME effects. Quiet is likely on July 28-29.
| 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 | ||||||||||
| 13376 | 2023.07.15 2023.07.17 |
7 | 10 | 6 | N23W82 | 0120 | DAO | DAC |
 |
 |
area: 0420 location: N22W76 |
| 13377 | 2023.07.17 2023.07.17 |
3 | 3 | 2 | S09W49 | 0230 | DAO | DHC |
 |
 |
area: 0410 location: S08W46 |
| S8775 | 2023.07.17 | S23W33 |
 |
||||||||
| 13378 | 2023.07.18 2023.07.19 |
1 | 1 | 1 | S28W84 | 0050 | HAX | HRX |
 |
 |
location: S27W81 |
| 13379 | 2023.07.18 2023.07.19 |
8 | 35 | 12 | N14W24 | 0255 | CKO | EKO |
 |
 |
area: 0380 location: N13W21 |
| S8782 | 2023.07.19 | N12W58 | |||||||||
| S8784 | 2023.07.20 | S43W14 | |||||||||
| S8786 | 2023.07.21 | N10W47 | |||||||||
| 13381 | 2023.07.22 2023.07.24 |
S18W85 |
 |
location: S18W80 | |||||||
| 13380 | 2023.07.22 2023.07.23 |
10 | 15 | 6 | S11E25 | 0110 | CSO | CAO |
 |
 |
area: 0200 location: S11E28 |
| S8790 | 2023.07.22 | N34W56 | |||||||||
| 13382 | 2023.07.24 | 1 | N18W19 | 0020 | HRX | this spot is part of AR 13379 | |||||
| 13383 | 2023.07.24 | 1 | N14W09 | 0010 | AXX | this spot is part of AR 13379 | |||||
| S8793 | 2023.07.24 | S04E17 | |||||||||
| S8794 | 2023.07.24 | N17E13 | |||||||||
| S8795 | 2023.07.24 | N24W39 |
 |
||||||||
| 13384 | 2023.07.24 2023.07.25 |
4 | 18 | 6 | S14E40 | 0010 | BXO | DRO |
 |
 |
area: 0050 location: S16E42 |
| S8797 | 2023.07.25 | N55W40 | |||||||||
| 13385 | 2023.07.25 2023.07.26 |
5 | 6 | 3 | S16W16 | 0040 | CAO | CSO |
 |
 |
location: S16W20 area: 0060 |
| S8799 | 2023.07.25 | N08W06 |
 |
||||||||
| 13386 | 2023.07.25 2023.07.26 |
7 | 15 | 10 | N11E60 | 0110 | DAO | DAI |
 |
 |
area: 0290 |
| S8801 | 2023.07.26 | 3 | 2 | N19E81 | 0270 | CKO |
 |
||||
| S8802 | 2023.07.26 | 3 | 2 | S22E77 | 0020 | CRO |
 |
||||
| S8803 | 2023.07.26 | 1 | 1 | N28W07 | 0002 | AXX |
 |
||||
| Total spot count: | 47 | 110 | 51 | ||||||||
| Sunspot number: | 147 | 220 | 161 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 90 | 169 | 110 | (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): | 162 | 121 | 129 | ||||||||
| 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 | 177.1 (1) | 118.3 (2A) / 141.1 (2B) / 149.1 (2C) | (135.4 projected, -0.5) | (8.4) | |
| 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.
