The geomagnetic field was quiet on May 3. Solar wind speed at SOHO ranged between 423 and 485 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 156.2 - increasing 19.1 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 140.10. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 2.4). Three hour interval K indices: 00001112 (planetary), 00112322 (Boulder), 11102215 (Andenes).
The background x-ray flux is 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: 245) and in 10 active regions using 1K resolution (SN: 167) SDO/HMI images.
Region 13288 [S22W80] rotated partly out of
view. The region produced many flares during the first half of the day. C1
flares: C1.9 @ 15:11, C1.9 @ 16:28 UT
Region 13289 [N20W28] decayed slowly and quietly.
Region 13293 [N13E37] became very active after 09 UT producing 6 M
flares. There are 2 small and very tight magnetic deltas in the central spot
section. Further M flares are likely.
Region 13294 [S08E58] was quiet and stable.
Region 13295 [N16W34] emerged on April 30 and was numbered by
SWPC 2 days later as the region began to decay.
Region 13296 [N16E49] developed further and could produce M flares.
C1 flares: C1.9 @ 20:27 UT
Region 13297 [N08E65] is a compact region with major flare potential.
C1 flares: C1.8 @ 17:55, C1.7 @ 19:27 UT
Spotted regions not observed (or interpreted
differently) by SWPC:
S8505 [N19E27] reemerged with tiny spots.
S8506 [S10W00] was quiet and stable.
New region S8525 [S16E47] emerged with several spots.
New region S8526 [S05E83] rotated partly into view. It is too early
to tell if the small leading spot is a separate region.
New region S8527 [N22W04] emerged with tiny spots.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C2.3 | 01:03 | 13288 | GOES18 | ||
| C2.5 | 03:02 | 13288 | GOES18 | ||
| C3.5 | 04:45 | 13288 | GOES18 | ||
| C3.0 | 04:50 | 13288 | GOES18 | ||
| C4.7 | 05:00 | 13288 | GOES18 | ||
| C3.3 | 07:23 | 13296 | GOES18 | ||
| C9.6 | 07:37 | 13288 | GOES18 | ||
| C5.2 | 09:12 | 13288 | GOES18 | ||
| M4.2 | 09:27 | 13293 | GOES18 | ||
| M3.1 | 10:14 | 13293 | GOES18 | ||
| M2.0 | 10:42 | 13293 | GOES18 | ||
| M7.2 | 10:45 | 13293 | GOES18 | ||
| C3.9 | 12:12 | 13293 | GOES18 | ||
| M1.7 | 12:35 | 13293 | GOES18 | ||
| M2.2 | 13:51 | 13293 | GOES18 | ||
| C2.4 | 14:23 | 13288 | GOES18 | ||
| C3.1 | 15:00 | 13293 | GOES18 | ||
| C3.0 | 18:22 | 13293 | GOES18 | ||
| C2.6 | 18:44 | 13296 | GOES18 | ||
| C4.1 | 20:53 | 13293 | GOES18 | ||
| C2.0 | 21:44 | 13296 | GOES18 | ||
| C2.5 | 22:37 | 13296 | GOES18 |
May 1-3: 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]
A southern hemisphere coronal hole (CH1144) was Earth facing on May 2-3. A recurrent northern hemisphere coronal hole (CH1145) could rotate across the central meridian on May 4.
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.
A quiet geomagnetic field is expected on May 4-5. Quiet to active conditions are possible on May 6-7 due to effects from CH1144.
| 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 | ||||||||||
| 13285 | 2023.04.20 2023.04.21 |
2 | S17W91 | 0030 | HSX |
 |
rotated out of view | ||||
| 13286 | 2023.04.21 2023.04.24 |
S11W84 | location: S11W78 | ||||||||
| 13287 | 2023.04.23 2023.04.24 |
S25W63 | location: S27W52 | ||||||||
| 13288 | 2023.04.24 2023.04.25 |
6 | 6 | 4 | S22W82 | 0120 | ESO | ESO |
 |
 |
|
| 13289 | 2023.04.25 2023.04.25 |
7 | 27 | 11 | N20W28 | 0030 | CRO | CRI |
 |
 |
area: 0050 |
| 13291 | 2023.04.25 2023.04.26 |
N07W89 |
 |
||||||||
| 13292 | 2023.04.25 2023.04.27 |
N14W26 |
 |
location: N17W20 | |||||||
| S8501 | 2023.04.27 | N21W58 | |||||||||
| S8505 | 2023.04.29 | 3 | N19E27 | 0003 | BXO |
 |
|||||
| S8506 | 2023.04.29 | 3 | 2 | S10W00 | 0010 | CRO |
 |
 |
|||
| 13293 | 2023.04.30 2023.04.30 |
12 | 21 | 11 | N13E35 | 0290 | DHC | EAC |
 |
 |
beta-delta area: 0350 location: N12E37 |
| S8507 | 2023.04.30 | N20W36 | |||||||||
| 13295 | 2023.04.30 2023.05.02 |
3 | 6 | 4 | N15W34 | 0010 | BXO | CRO |
 |
 |
location: N16W34 area: 0015 |
| S8509 | 2023.04.30 | S25E39 | |||||||||
| S8511 | 2023.04.30 | N09W30 | |||||||||
| S8512 | 2023.04.30 | S12W29 | |||||||||
| S8513 | 2023.04.30 | S31W35 | |||||||||
| S8514 | 2023.04.30 | N33E04 | |||||||||
| S8515 | 2023.05.01 | S11E16 |
 |
||||||||
| 13294 | 2023.05.01 2023.05.02 |
1 | 3 | 1 | S08E59 | 0120 | HSX | CSO |
 |
 |
area: 0220 location: S08E58 |
| S8517 | 2023.05.01 | N00W08 | |||||||||
| S8518 | 2023.05.01 | S03W30 |
 |
||||||||
| S8519 | 2023.05.01 | N16W43 | |||||||||
| S8520 | 2023.05.01 | S39W29 | |||||||||
| 13296 | 2023.05.02 2023.05.02 |
12 | 22 | 14 | N16E49 | 0170 | DAI | DAC |
 |
 |
beta-delta area: 0440 reversed polarities |
| 13297 | 2023.05.02 2023.05.02 |
20 | 22 | 16 | N08E64 | 0400 | DKI | EKC |
 |
 |
location: N08E65 area: 0950 |
| S8523 | 2023.05.02 | N06E13 |
 |
||||||||
| S8524 | 2023.05.02 | S07W22 |
 |
||||||||
| S8525 | 2023.05.03 | 6 | 3 | S16E47 | 0040 | CRO |
 |
||||
| S8526 | 2023.05.03 | 3 | 1 | S05E83 | 0030 | CRO |
 |
||||
| S8527 | 2023.05.03 | 3 | N23W04 | 0006 | BXO |
 |
|||||
| Total spot count: | 63 | 125 | 67 | ||||||||
| Sunspot number: | 143 | 245 | 167 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 106 | 170 | 112 | (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): | 157 | 135 | 134 | ||||||||
| 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 |
| 2021.09 | 87.0 | 88.2 | 51.3 | 40.2 (+4.8) | 6.33 |
| 2021.10 | 88.9 | 88.3 | 37.4 | 45.2 (+5.0) | 7.38 |
| 2021.11 | 86.2 | 84.4 | 34.8 | 50.8 (+5.6) | 9.83 |
| 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 | (100.4 projected, +1.7) | 9.33 |
| 2022.12 | 147.9 | 143.4 | 112.8 | (104.1 projected, +3.7) | 10.99 |
| 2023.01 | 182.4 | 176.6 | 143.6 | (110.1 projected, +6.0) | 8.73 |
| 2023.02 | 167.2 | 163.2 | 110.9 | (115.2 projected, +5.1) | 14.48 (current SC25 peak) |
| 2023.03 | 157.2 | 155.6 | 122.6 | (118.3 projected, +3.1) | 14.42 |
| 2023.04 | 145.4 | 146.4 | 96.4 | (123.7 projected, +5.4) | 13.3 |
| 2023.05 | 153.6 (1) | 11.7 (2A) / 121.3 (2B) / 145.9 (2C) | (129.3 projected, +5.6) | (6.3) | |
| 2023.06 | (132.5 projected, +3.2) | ||||
| 2023.07 | (132.0 projected, -0.5) | ||||
| 2023.08 | (133.0 projected, +1.0) | ||||
| 2023.09 | (136.4 projected, +3.4) | ||||
| 2023.10 | (138.3 projected, +1.9) | ||||
| 2023.11 | (141.4 projected, +3.1) | ||||
| 2023.12 | (142.5 projected max SC25) | ||||
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: SIDC-SILSO.
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.
