The geomagnetic field was quiet on August 3. Solar wind speed at SOHO ranged between 325 and 403 km/sec. The high latitude magnetometer at Andenes recorded quiet to unsettled levels.
Solar flux density measured at 20h UT on 2.8 GHz was 162.9 - increasing 1.5 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 150.59. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 5.1). Three hour interval K indices: 22122100 (planetary), 1212341* (Boulder), 32233310 (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 16 active regions using 2K resolution (SN: 301) and in 13 active regions using 1K resolution (SN: 185) SDO/HMI images.
Region 13386 [N10W35] decayed slowly in the
trailing spot section. New negative polarity flux emerged to the east of the
main penumbra, this development may have contributed to an M1.9 long
duration flare peaking at 04:23 UT on August 4. A CME was observed off the
west limb shortly afterwards. C1 flares: C1.5 @ 16:43, C1.7 @ 19:23 UT
Region 13387 [N21W09] was quiet and stable.
Region 13388 [S23W16] decayed slowly and quietly.
Region 13389 [S10W03] decayed slowly and quietly.
Region 13390 [S19E08] decayed slowly and was quiet.
Region 13391 [N23E26] was quiet and stable.
Region 13392 [N09E21] developed slowly and quietly.
Region 13393 [N17W01] was quiet and stable.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S8813 [S10W78] produced many C flares and the
only M flare of the day. In general, flares were less frequent and of
smaller magnitude than during the previous day.
S8814 [N18E32] regained tiny trailing spots and was quiet.
S8817 [S09E05] decayed slowly and was quiet.
New region S8820 [S16W30] was observed with tiny spots in an
old plage area.
New region S8821 [N32E84] rotated into view with a tiny spot.
New region S8822 [S11E34] was observed with a tiny spot in an old
plage area.
A weak solar wind shock was observed at 06:52 UT on August 4 at DSCOVR, probably the arrival of the July 31 CME.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C3.7 | 01:38 | S8813 | GOES16 | ||
| C3.3 | 02:02 | 13392 | GOES16 | ||
| C4.1 | 02:14 | 13394 | GOES16 | ||
| C4.0 | 02:25 | S8813 | GOES16 | ||
| C3.7 | 02:51 | S8813 | GOES16 | ||
| C3.4 | 03:31 | S11W65 | S8813 | GOES16 | |
| C2.9 | 04:34 | S8813 | GOES16 | simultaneous flare in AR 13394 | |
| C2.8 | 05:02 | S8813 | GOES16 | ||
| C2.1 | 05:24 | S8813 | GOES16 | ||
| C2.2 | 05:29 | S8813 | GOES16 | ||
| C2.2 | 05:38 | S8813 | GOES16 | ||
| C2.6 | 05:53 | S12W71 | S8813 | GOES16 | |
| C3.0 | 06:21 | S10W64 | S8813 | GOES16 | |
| C2.9 | 06:31 | S8813 | GOES16 | ||
| C3.6 | 07:14 | GOES16 | |||
| C3.3 | 07:57 | S8813 | GOES16 | ||
| C3.6 | 08:50 | S8813 | GOES16 | ||
| C6.4 | 09:04 | S8813 | GOES16 | ||
| C2.0 | 10:40 | S8813 | GOES16 | ||
| C2.3 | 11:14 | S8813 | GOES16 | ||
| M2.0 | 11:55 | S13W75 | S8813 | GOES16 | |
| C2.7 | 12:42 | S8813 | GOES16 | ||
| C2.5 | 13:10 | S8813 | GOES16 | ||
| C3.6 | 13:39 | S8813 | GOES16 | ||
| C3.7 | 13:49 | 13394 | GOES16 | ||
| C2.1 | 15:53 | S8813 | GOES16 | ||
| C2.1 | 17:42 | S8813 | GOES16 | ||
| C2.1 | 18:03 | S8813 | GOES16 | ||
| C2.3 | 18:48 | 13394 | GOES16 | ||
| C2.8 | 18:54 | 13394 | GOES16 | ||
| C5.0 | 20:20 | N10E14 | 13392 | GOES16 | |
| C3.1 | 22:09 | S8813 | GOES16 | ||
| C7.9 | 23:49 | S8813 | GOES16 |
July 31: Several filaments erupted during the latter half of the day.
A slow moving partial halo CME was observed starting at 23:00 UT in LASCO C2
imagery. Components of this CME could reach Earth on August 4.
August 1: No obviously Earth directed CMEs were observed.
August 2: A faint full halo CME was observed after a filament
eruption near AR 13386. The CME was visible in LASCO C2 imagery from 09:12
UT. The CME is likely to reach Earth sometime late on August 4 or early on
August 5.
August 3: 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 quiet to minor storm on August 4-5 due to CME effects. Quiet to unsettled is likely on August 6.
| 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 | ||||||||||
| 13380 | 2023.07.22 2023.07.23 |
10 | S11W80 | 0330 | EKI |
location: S17W64 AR S8813 was split off on July 30 |
|||||
| 13384 | 2023.07.24 2023.07.25 |
S17W64 | part of AR 13380 | ||||||||
| 13386 | 2023.07.25 2023.07.26 |
6 | 24 | 10 | N12W45 | 0180 | DSO | DHO |
 |
 |
area: 0330 location: N10W49 |
| 13387 | 2023.07.26 2023.07.27 |
5 | 17 | 6 | N22W21 | 0050 | CSO | CSO |
 |
 |
area: 0130 location: N21W22 |
| 13388 | 2023.07.26 2023.07.27 |
1 | 11 | 3 | S23W30 | 0010 | AXX | CRO |
 |
 |
area: 0030 |
| 13389 | 2023.07.27 2023.07.27 |
7 | 1 | S09W19 | 0010 | BXO |
 |
 |
location: S11W11 |
||
| S8806 | 2023.07.27 | S15W29 | |||||||||
| 13390 | 2023.07.28 2023.07.27 |
7 | 2 | S20W08 | 0010 | BXO |
 |
 |
location: S20W05 |
||
| 13391 | 2023.07.28 2023.07.29 |
1 | 9 | 3 | N23E13 | 0090 | HSX | CSO |
 |
 |
area: 0160 location: N23E12 |
| 13392 | 2023.07.29 2023.07.31 |
7 | 26 | 14 | N10E10 | 0160 | ESO | EHO |
 |
 |
area: 0360 location: N09E07 |
| S8811 | 2023.07.29 | S08W53 |
 |
||||||||
| 13393 | 2023.07.29 2023.07.31 |
1 | 3 | 1 | N16W03 | 0010 | AXX | AXX |
 |
 |
location: N17W01 |
| S8813 | 2023.07.30 | 12 | 5 | S10W78 | 0420 | DAC |
 |
 |
split off from AR 13380 |
||
| S8814 | 2023.07.31 | 9 | 2 | N18E32 | 0020 | BXO |
 |
 |
|||
| S8815 | 2023.08.01 | N16W42 | |||||||||
| 13394 | 2023.08.02 2023.08.03 |
2 | 8 | 4 | S22E61 | 0130 | HSX | CHO |
 |
 |
area: 0300 |
| S8817 | 2023.08.02 | 2 | 2 | S09E05 | 0008 | BXO |
 |
 |
|||
| S8818 | 2023.08.02 | N17E42 |
 |
||||||||
| 13395 | 2023.08.03 | 1 | 2 | 2 | N15E75 | 0060 | HSX | DSO |
 |
was AR S8819 location: N13E79 area: 0150 |
|
| S8820 | 2023.08.03 | 2 | S16W30 | 0005 | AXX |
 |
|||||
| S8821 | 2023.08.03 | 1 | N32E84 | 0002 | AXX |
 |
|||||
| S8822 | 2023.08.03 | 1 | S11E34 | 0002 | AXX |
 |
|||||
| Total spot count: | 34 | 141 | 55 | ||||||||
| Sunspot number: | 124 | 301 | 185 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 74 | 194 | 108 | (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): | 136 | 166 | 148 | ||||||||
| 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 |
| 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 | 113.3 (+6.7) | 8.73 |
| 2023.02 | 167.2 | 163.2 | 110.9 | (119.1 projected, +5.8) | 14.48 (current SC25 peak) |
| 2023.03 | 157.2 | 155.6 | 122.6 | (124.4 projected, +5.3) | 14.42 |
| 2023.04 | 145.4 | 146.4 | 96.4 | (130.5 projected, +6.1) | 13.40 |
| 2023.05 | 155.6 | 159.2 | 137.9 | (136.1 projected, +5.6) | 10.67 |
| 2023.06 | 161.7 | 166.8 | 163.4 | (139.3 projected, +3.2) | 8.95 |
| 2023.07 | 176.4 | 182.2 | 159.1 | (139.7 projected, +0.4) | 8.1 |
| 2023.08 | 170.2 (1) | 13.5 (2A) / 139.7 (2B) / 149.4 (2C) | (141.5 projected, +1.8) | (8.3) | |
| 2023.09 | (145.0 projected, +3.5) | ||||
| 2023.10 | (146.8 projected, +1.8) | ||||
| 2023.11 | (149.4 projected max SC25, +2.6) | ||||
| 2023.12 | (148.6 projected, -0.8) | ||||
| 2024.01 | (145.7 projected, -2.9) | ||||
| 2024.02 | (144.3 projected, -1.4) | ||||
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.
