The geomagnetic field was quiet to unsettled on August 1, weakly under the influence of CME effects after noon. Solar wind speed at SOHO ranged between 344 and 435 km/sec. The high latitude magnetometer at Andenes recorded quiet to active levels.
Solar flux density measured at 20h UT on 2.8 GHz was 174.7 - increasing 20.1 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 150.20. 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: 7.8). Three hour interval K indices: 22113322 (planetary), 22123423 (Boulder), 43114344 (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 12 active regions using 2K resolution (SN: 298) and in 12 active regions using 1K resolution (SN: 201) SDO/HMI images.
Region 13380 [S17W38] decayed slowly and
quietly. This is AR 13384 to SWPC.
Region 13386 [N10W21] decayed slowly and was mostly quiet.
Region 13387 [N21E04] was quiet and stable.
Region 13388 [S24W03] decayed slowly and quietly.
Region 13389 [S09E08] decayed slowly and quietly.
Region 13390 [S19E20] decayed slowly and was mostly quiet.
Region 13391 [N23E39] gained a few spots to the north of the main
spot.
Region 13392 [N09E34] developed further and was mostly quiet.
Region 13393 [N17E12] decayed slowly and quietly
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S8813 [S11W52] produced many C and M flares.
The region has several magnetic delta structures and an X class flare is
possible.
S8814 [N17E53] decayed slowly and quietly.
New region S8815 [N16W16] emerged just north of AR 13386, slow decay was observed after noon.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C4.1 | 00:15 | S8813 | GOES16 | ||
| C4.4 | 00:23 | behind northwest limb | 13379 | GOES16 | |
| C4.5 | 01:28 | S8813 | GOES16 | ||
| M1.2 | 02:03 | S08E39 | S8813 | GOES16 | |
| C3.4 | 03:55 | S8813 | GOES16 | ||
| C3.6 | 04:13 | S8813 | GOES16 | ||
| M2.2/1N | 04:47 | S10W41 | S8813 | GOES16 | |
| M1.3 | 05:37 | S8813 | GOES16 | ||
| M3.6 | 06:57 | S8813 | GOES16 | ||
| M2.3 | 07:34 | S8813 | GOES16 | ||
| C8.3 | 08:07 | S8813 | GOES16 | ||
| C3.3 | 08:58 | S8813 | GOES16 | ||
| M1.5 | 09:09 | S8813 | GOES16 | ||
| C8.5 | 09:46 | S8813 | GOES16 | ||
| C6.5 | 10:57 | southeast limb | GOES16 | simultaneous flare in AR S8813 | |
| C5.5 | 12:44 | S17W32 | 13380 | GOES16 | |
| M1.4/1N | 14:09 | S10W45 | S8813 | GOES16 | |
| C4.7 | 15:08 | S8813 | GOES16 | ||
| C3.8 | 15:39 | S8813 | GOES16 | ||
| C3.5 | 15:53 | S8813 | GOES16 | ||
| C3.0 | 16:34 | S8813 | GOES16 | ||
| C2.9 | 18:55 | S8813 | GOES16 | ||
| C3.4 | 19:13 | S8814 | GOES16 | ||
| C5.2 | 20:08 | N17E58 | S8814 | GOES16 | LDE |
| M1.0 | 21:51 | S8813 | GOES16 | ||
| C2.3 | 23:00 | S8813 | GOES16 | ||
| C2.8 | 23:31 | S8813 | GOES16 | ||
| C2.8 | 23:39 | 13390 | 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.
July 30, August 1: 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 unsettled on August 2-4, on August 2 due to weak effects from the July 28 CME. Another CME could reach Earth on August 4 but is not expected to cause a significant 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 | ||||||||||
| 13380 | 2023.07.22 2023.07.23 |
21 | 8 | 3 | S10W55 | 0190 | DAC | BXO |
 |
 |
location: S17W38 area: 0020 AR S8813 was split off on July 30 |
| 13384 | 2023.07.24 2023.07.25 |
5 | S18W39 | 0010 | CAO | part of AR 13380 | |||||
| 13386 | 2023.07.25 2023.07.26 |
16 | 27 | 14 | N14W18 | 0150 | EAI | EHO |
 |
 |
beta-gamma area: 0340 location: N10W21 |
| 13387 | 2023.07.26 2023.07.27 |
6 | 18 | 6 | N22E03 | 0050 | CSO | CSO |
 |
 |
area: 0160 location: N21E04 |
| 13388 | 2023.07.26 2023.07.27 |
1 | 8 | 4 | S23W06 | 0010 | CRO | CRO |
 |
 |
area: 0030 location: S24W03 |
| 13389 | 2023.07.27 2023.07.27 |
2 | 13 | 7 | S08E07 | 0020 | HSX | CRI |
 |
 |
area: 0040 location: S09E08 |
| S8806 | 2023.07.27 | S15W03 | |||||||||
| 13390 | 2023.07.28 2023.07.27 |
2 | 8 | 5 | S18E19 | 0020 | DSO | CRO |
 |
 |
location: S19E20 |
| 13391 | 2023.07.28 2023.07.29 |
1 | 7 | 5 | N25E37 | 0050 | HSX | CSO |
 |
 |
area: 0200 location: N23E39 |
| 13392 | 2023.07.29 2023.07.31 |
3 | 33 | 16 | N09E30 | 0040 | DAO | DAI |
 |
 |
area: 0240 location: N09E34 |
| S8811 | 2023.07.29 | S07W25 | |||||||||
| 13393 | 2023.07.29 2023.07.31 |
3 | 4 | 3 | N18E12 | 0010 | CSO | BXO |
 |
 |
location: N17E12 |
| S8813 | 2023.07.30 | 40 | 15 | S11W52 | 0670 | DKC | DAC |
 |
 |
beta-delta split off from AR 13380 |
|
| S8814 | 2023.07.31 | 6 | 1 | N17E53 | 0007 | BXO |
 |
 |
|||
| S8815 | 2023.08.01 | 6 | 2 | N16W16 | 0013 | BXO |
 |
||||
| Total spot count: | 60 | 178 | 81 | ||||||||
| Sunspot number: | 160 | 298 | 201 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 108 | 217 | 120 | (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): | 176 | 164 | 161 | ||||||||
| 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 | 174.7 (1) | 5.2 (2A) / 160 (2B) / 151.1 (2C) | (141.5 projected, +1.8) | (7.8) | |
| 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.
