The geomagnetic field was at quiet to unsettled levels on July 29. Solar wind speed at SOHO ranged between 357 and 395 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 178.6 - increasing 8.4 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 149.51. 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: 8.5). Three hour interval K indices: 00012133 (planetary), 10112322 (Boulder), 55124441 (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 14 active regions using 2K resolution (SN: 281) and in 14 active regions using 1K resolution (SN: 211) SDO/HMI images.
Region 13377 [S08W86] rotated partly out of
view and was quiet.
Region 13379 [N13W62] decayed slowly and was mostly quiet.
Region 13380 [S11W12] continued to develop in the northwestern
section. The spots in that section could be regarded as a new region,
however, they are so close to the former leader spot of the spot group that
it is difficult to separate the regions. Further M flares are possible.
Region 13385 [S16W63] decayed slowly and quietly.
Region 13386 [N11E20] decayed in the trailing spot section and was
less active than during the previous days.
Region 13387 [N20E42] was quiet and stable.
Region 13388 [S23E35] was quiet and stable.
Region 13389 [S09E48] was mostly quiet and stable. C1 flares: C1.6 @
01:08 UT
Region 13390 [S19E60] produced a few flares despite having only a few
small spots. C1 flares: C1.5 @ 05:41 UT
New region 13391 [N24E77] rotated partly into view on July 28 and was
numbered by SWPC the next day. C1 flares: C1.5 @ 03:59 UT
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
New region S8809 [S18W01] emerged before noon
with tiny spots near the trailing spot section of AR 13380.
New region S8810 [N09E78] rotated into view with tiny spots.
New region S8811 [S05E19] emerged with a tiny spot.
New region S8812 [N17E53] emerged with tiny spots.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C2.7 | 02:19 | behind northwest limb | 13376 | GOES16 | |
| C2.9 | 02:31 | behind northwest limb | 13376 | GOES16 | |
| C2.2 | 06:02 | S08E70 | 13389 | GOES16 | |
| C6.7 | 07:34 | behind northeast limb | GOES16 | LDE, CME | |
| C3.3 | 08:43 | 13386 | GOES16 | ||
| C2.4 | 10:04 | 13386 | GOES16 | ||
| C9.2 | 10:36 | S18E68 | 13390 | GOES16 | |
| C4.2 | 11:15 | 13386 | GOES16 | ||
| C2.3 | 12:44 | 13389 | GOES16 | ||
| C5.5 | 13:20 | S09W08 | 13380 | GOES16 | |
| C2.4 | 15:32 | 13380 | GOES16 | ||
| M1.4/1N | 16:24 | 13380 | GOES16 | ||
| C4.3 | 17:07 | 13390 | GOES16 | ||
| C2.8 | 20:10 | 13386 | GOES16 | ||
| C2.1 | 22:12 | 13386 | GOES16 | ||
| C4.9 | 23:40 | 13379 | GOES16 |
July 27, 29: No obviously Earth directed CMEs were observed.
July 28: A large filament eruption was observed beginning in the
northeast quadrant at approximately 20:47 UT in SDO AIA imagery, and with a
peak after 22h UT. A faint full halo CME was observed in LASCO C2 imagery
beginning at 22:36 UT. The most likely source of the CME is the
aforementioned filament eruption. The brightest ejecta was off the southeast
limb. The CME could reach Earth late on July 31 or early on August 1.
[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 small coronal hole (CH1162) formed in the northeast quadrant near the central meridian after the filament eruption on July 28. Coronal holes generated by such eruptions are generally speaking short lived, and CH1162 closed on July 29.
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 to unsettled on July 30-31. Late on July 31 or on August 1 the July 28 could reach Earth and cause unsettled to minor storm conditions. Effects from CH1162 could reach Earth on August 1 and contribute to the expected disturbance.
| Coronal holes (1) | Coronal mass ejections (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 | ||||||||||
| 13377 | 2023.07.17 2023.07.17 |
2 | 1 | 1 | S08W87 | 0140 | DSO | HSX |
 |
 |
|
| 13379 | 2023.07.18 2023.07.19 |
1 | 8 | 2 | N14W63 | 0180 | HSX | CHO |
 |
 |
area: 0270 location: N13W62 |
| S8784 | 2023.07.20 | S43W53 | |||||||||
| 13380 | 2023.07.22 2023.07.23 |
16 | 42 | 22 | S10W12 | 0230 | DAI | DAI |
 |
 |
beta-gamma location: S11W12 area: 0360 merged with AR 13384 on July 27 |
| 13382 | 2023.07.24 | N19W59 | part of AR 13379 | ||||||||
| 13383 | 2023.07.24 | N15W49 | part of AR 13379 | ||||||||
| S8793 | 2023.07.24 | S04W22 | |||||||||
| S8794 | 2023.07.24 | N17W26 | |||||||||
| 13384 | 2023.07.24 2023.07.25 |
S16E04 | see AR 13380 | ||||||||
| 13385 | 2023.07.25 2023.07.26 |
1 | 1 | 1 | S15W64 | 0010 | AXX | HRX |
 |
 |
location: S16W63 |
| S8799 | 2023.07.25 | N08W45 | |||||||||
| 13386 | 2023.07.25 2023.07.26 |
12 | 34 | 17 | N12E20 | 0300 | DKI | EHI |
 |
 |
area: 0510 location: N11E20 |
| 13387 | 2023.07.26 2023.07.27 |
5 | 14 | 5 | N20E42 | 0120 | CAO | CAO |
 |
 |
area: 0170 |
| 13388 | 2023.07.26 2023.07.27 |
5 | 10 | 5 | S23E36 | 0060 | CSO | CSO |
 |
 |
area: 0110 |
| S8803 | 2023.07.26 | N28W46 | |||||||||
| 13389 | 2023.07.27 2023.07.27 |
1 | 10 | 6 | S09E47 | 0040 | HSX | CAO |
 |
 |
location: S09E48 area: 0130 |
| S8806 | 2023.07.27 | S15E36 | |||||||||
| 13390 | 2023.07.28 2023.07.27 |
3 | 8 | 5 | S19E58 | 0030 | CRO | DRO |
 |
 |
ocation: S19E60 area: 0110 |
| 13391 | 2023.07.28 2023.07.29 |
1 | 3 | 1 | N25E75 | 0030 | HSX | CSO |
 |
 |
area: 0190 location: N24E77 |
| S8809 | 2023.07.29 | 4 | 2 | S18W41 | 0012 | BXO |
 |
||||
| S8810 | 2023.07.29 | 2 | 1 | N09E78 | 0008 | AXX |
 |
||||
| S8811 | 2023.07.29 | 1 | 1 | S05E19 | 0004 | AXX |
 |
||||
| S8812 | 2023.07.29 | 3 | 2 | N17E53 | 0010 | CRO |
 |
||||
| Total spot count: | 47 | 141 | 71 | ||||||||
| Sunspot number: | 147 | 281 | 211 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 95 | 200 | 130 | (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 | 155 | 169 | ||||||||
| 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 | 176.4 (1) | 132.8 (2A) / 142.0 (2B) / 149.5 (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.
