The geomagnetic field was quiet to active on July 25. Solar wind speed at SOHO ranged between 369 and 555 km/sec. The high latitude magnetometer at Andenes recorded quiet to minor storm levels. A solar wind shock was recorded at ACE at 21:53 UT, probably the arrival of the July 22 CME.
Solar flux density measured at 20h UT on 2.8 GHz was 169.0 - increasing 14.1 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 148.67. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.3). Three hour interval K indices: 11212124 (planetary), 11223325 (Boulder), 21114545 (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 13 active regions using 2K resolution (SN: 263) and in 12 active regions using 1K resolution (SN: 179) SDO/HMI images.
Region 13373 [N09W75] decayed further and lost
all leading and intermediate spots.
Region 13376 [N22W63] developed further with the leading and trailing
penumbrae merging before noon. Later on some separation was observed.
Further M class flares are likely. C1 flares: C1.8 @ 18:14, C1.9 @ 22:47 UT
Region 13377 [S08W33] the two largest opposite polarity penumbrae drifted
even closer to each other and the region has become compact. An M flare is
possible.
Region 13378 [S27W68] decayed slowly and quietly.
Region 13379 [N13W08] has many small and tiny spots in addition to
the large leading penumbra. The spot group was quiet.
Region 13380 [S12E42] has a fairly complex magnetic layout with
significant polarity intermixing. Although the spot group decayed slightly,
an M flare is possible. C1 flares: C1.4 @ 12:01 UT
Region 13381 [S18W67] decayed slowly and quietly.
New region 13384 [S15E56] rotated partly into view on July 23 and was
numbered by SWPC 2 days later.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S8775 [S23W20] decayed slowly and quietly.
S8795 [N24W26] was spotless early in the day,
then reemerged with a tiny spot.
New region S8798 [S15W03] emerged with several spots.
New region S8799 [N09E07] emerged just south of AR 13379 with many
tiny spots.
New region S8800 [N12E75] emerged near the northeast limb with tiny
spots.
AR S8797 was numbered at noon when it had 1 spot and was located at a high latitude (N55W21). The spot disappeared during the afternoon.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C2.4 | 00:40 | 13380 | GOES16 | incorrectly attributed to AR 13376 by SWPC | |
| M1.5/2N | 02:03 | N25W49 | 13376 | GOES16 | |
| C2.3 | 03:55 | 13379 | GOES16 | ||
| C2.6 | 06:05 | 13373 | GOES16 | ||
| C2.5 | 06:09 | 13380 | GOES16 | ||
| C3.9 | 07:00 | S12E51 | 13380 | GOES16 | |
| C3.2 | 08:21 | S12E51 | 13380 | GOES16 | |
| C3.2 | 12:46 | 13373 | GOES16 | ||
| C2.6 | 14:40 | behind northwest limb | GOES16 | LDE | |
| C2.2 | 16:11 | 13380 | GOES16 | ||
| C2.0 | 16:52 | 13373 | GOES16 | ||
| C2.0 | 18:49 | S8800? | GOES16 | uncertain origin | |
| C2.8 | 20:39 | 13376 | GOES16 | ||
| C4.1 | 20:56 | 13376 | GOES16 | incorrectly attributed to AR 13380 by SWPC | |
| M1.6/1B | 21:16 | S09E42 | 13380 | GOES16 | |
| C4.3 | 23:53 | 13379 | GOES16 | incorrectly attributed to small, simultaneous flare in AR 13376 by SWPC |
July 23: A C5 flare peaked at 14:44 in AR 13376. LASCO C2 imagery
displays the leading edge of a CME at 15:05 UT. This CME was subsequently
observed as a slowly expanding full halo CME in LASCO C3. The CME will
likely reach Earth on July 26 or early on July 27.
July 24: No obviously Earth directed CMEs were
observed. A backsided full halo CME from a source a few days behind the
southwest limb was in progress in LASCO C2 imagery at 18:12 UT. This event
was also associated with an increase in proton levels shortly afterwards.
July 25: 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 to fair.
The geomagnetic field is expected to be at unsettled to minor storm levels on July 26-27 due to CME effects. Quiet to unsettled 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 | ||||||||||
| 13373 | 2023.07.13 2023.07.14 |
3 | 4 | 2 | N08W86 | 0150 | DAO | HAX |
 |
 |
location: N09W75 area: 0200 SWPC location is way off |
| 13374 | 2023.07.13 2023.07.14 |
S08W82 | location: S09W73 | ||||||||
| 13376 | 2023.07.15 2023.07.17 |
6 | 18 | 8 | N23W68 | 0120 | DAI | DKC |
 |
 |
area: 0540 location: N22W63 |
| 13377 | 2023.07.17 2023.07.17 |
3 | 5 | 3 | S09W35 | 0260 | DHO | DHC |
 |
 |
area: 0450 location: S08W33 |
| S8775 | 2023.07.17 | 2 | S23W20 | 0004 | AXX |
 |
 |
||||
| 13378 | 2023.07.18 2023.07.19 |
1 | 2 | 1 | S28W70 | 0040 | HAX | HAX |
 |
 |
area: 0050 location: S27W68 |
| 13379 | 2023.07.18 2023.07.19 |
8 | 41 | 13 | N14W10 | 0260 | DKO | EKO |
 |
 |
area: 0450 |
| S8781 | 2023.07.18 | N15W50 | |||||||||
| S8782 | 2023.07.19 | N12W45 | |||||||||
| S8784 | 2023.07.20 | S43W01 | |||||||||
| S8786 | 2023.07.21 | N10W34 | |||||||||
| 13381 | 2023.07.22 2023.07.24 |
1 | 3 | 1 | S18W71 | 0010 | AXX | AXX |
 |
 |
location: S18W67 area: 0006 |
| 13380 | 2023.07.22 2023.07.23 |
7 | 20 | 14 | S11E39 | 0230 | CAO | DAI |
 |
 |
beta-gamma area: 0270 location: S12E42 |
| S8790 | 2023.07.22 | N34W43 | |||||||||
| 13382 | 2023.07.24 | 1 | N18W05 | 0020 | HAX | this spot is part of AR 13379 | |||||
| 13383 | 2023.07.24 | 3 | N14E05 | 0010 | BXO | these spots are part of AR 13379 | |||||
| S8793 | 2023.07.24 | S04E30 |
 |
||||||||
| S8794 | 2023.07.24 | N17E26 |
 |
||||||||
| S8795 | 2023.07.24 | 1 | 1 | N24W26 | 0004 | HRX |
 |
 |
|||
| 13384 | 2023.07.24 2023.07.25 |
4 | 15 | 5 | S14E54 | 0010 | BXO | CRI |
 |
 |
area: 0040 location: S15E56 |
| S8797 | 2023.07.25 | N55W27 |
 |
||||||||
| S8798 | 2023.07.25 | 8 | 5 | S15W03 | 0050 | DRO |
 |
||||
| S8799 | 2023.07.25 | 10 | 5 | N08E07 | 0025 | CRO |
 |
||||
| S8800 | 2023.07.25 | 4 | 1 | N12E75 | 0010 | BXO |
 |
||||
| Total spot count: | 37 | 133 | 59 | ||||||||
| Sunspot number: | 137 | 263 | 179 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 82 | 190 | 116 | (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): | 151 | 145 | 143 | ||||||||
| 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 | 177.5 (1) | 113.6 (2A) / 140.8 (2B) / 150.5 (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.
