The geomagnetic field was quiet on July 24. Solar wind speed at SOHO ranged between 372 and 451 km/sec. The high latitude magnetometer at Andenes recorded quiet to minor storm levels.
Solar flux density measured at 20h UT on 2.8 GHz was 165.1 - increasing 13.9 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 148.48. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 5.6). Three hour interval K indices: 21222122 (planetary), 22112222 (Boulder), 43123105 (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 12 active regions using 2K resolution (SN: 249) and in 10 active regions using 1K resolution (SN: 161) SDO/HMI images.
Region 13373 [N08W63] decayed further and
produced a few low level C flares. C1 flares: C1.9 @ 16:43 UT
Region 13376 [N22W50] developed and became more complex. An M1.5
flare was recorded at 02:03 UT on July 25. C1 flares: C1.5 @ 18:38, C1.3 @
19:19 UT
Region 13377 [S08W19] was quiet and stable. The two opposite polarity
main spots drifted closer to each other. Should this development continue,
then the region will likely become more unstable.
Region 13378 [S26W54] decayed slowly and quietly.
Region 13379 [N14E05] was mostly unchanged and quiet. The region is
extensive both longitudinally and latitudinally.
Region 13380 [S12E57] has a fairly complex magnetic layout with
significant polarity intermixing. An M flare is possible. C1 flares: C1.7 @
09:27, C1.4 @ 12:04 UT
New region 13381 [S18W55] emerged on July 22 and was numbered by SWPC
two days later as the region began to decay. C1 flares: C1.9 @ 02:35 UT
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S8775 [S23W15] was quiet and stable.
New region S8793 [S04E43] emerged with a tiny spot.
New region S8794 [N17E43] emerged with a tiny spot.
New region S8795 [N23W12] emerged with tiny spots.
New region S8796 [S15E68] rotated into view.
The region is fairly close to AR 13830, however, this seems to be a separate
spot group.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C8.4/2N | 00:21 | N16E24 | 13379 | GOES16 | |
| C3.4 | 01:50 | S13E71 | 13380 | GOES16 | simultaneous flare in AR 13381 |
| C2.0 | 02:18 | 13380 | GOES16 | ||
| C9.1 | 04:26 | 13372 | GOES16 | LDE | |
| C8.5 | 05:43 | N26W80 | 13372 | GOES16 | LDE |
| C4.2 | 07:56 | 13380 | GOES16 | ||
| C2.2 | 15:17 | N09W61 | 13373 | GOES16 | |
| C2.5 | 17:45 | 13380 | GOES16 | ||
| C2.8 | 18:00 | N08W64 | 13373 | GOES16 | |
| C2.3 | 23:30 | N04W71 | 13373 | GOES16 |
July 22: An extensive filament eruption
was observed beginning in the northeast quadrant at approximately 20:28 UT.
A partial halo CME was observed off the northeast limb and the north pole.
It is uncertain if the CME has any Earth directed components.
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.
[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 quiet on July 25. There is some uncertainty regarding the July 22 CME. If there is an Earth directed component, we could see unsettled to active conditions on July 25 and 26. The July 23 CME could reach Earth on July 26 or early on July 27 and cause unsettled to minor storm intervals
| 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 | ||||||||||
| 13372 | 2023.07.11 2023.07.11 |
1 | N24W91 | 0120 | HSX |
 |
rotated out of view location: N23W94 |
||||
| 13373 | 2023.07.13 2023.07.14 |
13 | 16 | 7 | N08W71 | 0240 | EAO | EAO |
 |
 |
location: N08W63 area: 0300 |
| 13374 | 2023.07.13 2023.07.14 |
S08W67 | location: S09W60 | ||||||||
| S8771 | 2023.07.15 | S32W57 | |||||||||
| 13376 | 2023.07.15 2023.07.17 |
4 | 23 | 12 | N23W53 | 0070 | DAO | DAO |
 |
 |
area: 0200 location: N22W50 |
| 13377 | 2023.07.17 2023.07.17 |
5 | 7 | 3 | S09W21 | 0260 | DHO | DHO |
 |
 |
area: 0440 location: S08W19 |
| S8775 | 2023.07.17 | 4 | 2 | S23W15 | 0010 | AXX |
 |
 |
|||
| 13378 | 2023.07.18 2023.07.19 |
1 | 3 | 3 | S26W56 | 0030 | HAX | HAX |
 |
 |
area: 0050 location: S26W54 |
| 13379 | 2023.07.18 2023.07.19 |
5 | 33 | 14 | N14E05 | 0280 | DKO | FHO |
 |
 |
area: 0480 |
| S8781 | 2023.07.18 | N15W37 |
 |
||||||||
| S8782 | 2023.07.19 | N12W32 | |||||||||
| S8784 | 2023.07.20 | S43E12 | |||||||||
| S8786 | 2023.07.21 | N10W21 | |||||||||
| 13381 | 2023.07.22 2023.07.24 |
4 | 9 | 5 | S18W57 | 0010 | BXO | CRO |
 |
 |
location: S18W55 area: 0020 |
| 13380 | 2023.07.22 2023.07.23 |
6 | 19 | 10 | S11E54 | 0120 | CAO | DAI |
 |
 |
area: 0300 location: S12E57 |
| S8790 | 2023.07.22 | N34W30 |
 |
||||||||
| S8791 | 2023.07.23 | S13W52 |
 |
||||||||
| 13382 | 2023.07.24 | 1 | N19E10 | 0010 | HSX | this spot is part of AR 13379 | |||||
| 13383 | 2023.07.24 | 1 | N14E20 | 0005 | AXX | this spot is part of AR 13379 | |||||
| S8793 | 2023.07.24 | 1 | 1 | S04E43 | 0003 | AXX |
 |
||||
| S8794 | 2023.07.24 | 1 | N17E39 | 0001 | AXX |
 |
|||||
| S8795 | 2023.07.24 | 3 | N23W12 | 0004 | BXO |
 |
|||||
| S8796 | 2023.07.24 | 10 | 4 | S15E68 | 0040 | CRI |
 |
||||
| Total spot count: | 41 | 129 | 61 | ||||||||
| Sunspot number: | 141 | 249 | 161 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 91 | 175 | 107 | (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): | 155 | 137 | 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 | 177.9 (1) | 109.2 (2A) / 141.0 (2B) / 151.2 (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.
