The geomagnetic field was quiet to unsettled on May 2 with activity decreasing during the latter half of the day. Solar wind speed at SOHO ranged between 476 and 588 km/sec. The high latitude magnetometer at Andenes recorded quiet to major storm levels.
Solar flux density measured at 20h UT on 2.8 GHz was 156.8 - increasing 20.2 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 139.98. 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: 8.1). Three hour interval K indices: 33231111 (planetary), 33332321 (Boulder), 65432232 (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 16 active regions using 2K resolution (SN: 280) and in 13 active regions using 1K resolution (SN: 195) SDO/HMI images.
Region 13285 [S17W77] decayed slowly and
quietly.
Region 13288 [S22W72] decayed further losing spots, area and the
magnetic delta. C1 flares: C1.8 @ 04:58, C1.3 @ 10:32, C1.3 @ 17:00 UT
Region 13289 [N20W13] decayed slowly and was mostly quiet. C1 flares:
C1.8 @ 02:44 UT
Region 13291 [N07W74] decayed slowly and quietly.
Region 13292 [N17W07] was quiet and stable.
Region 13293 [N13E50] appeared to mature and was significantly less
active than on the previous day. The region has a magnetic delta in a
central penumbra and could produce an M class flare. C1 flare: C1.9 @ 01:56,
C1.3 @ 13:49, C1.4 @ 14:28 UT
New region 13294 [S08E71] rotated into view on May 1 and was numbered
by SWPC the next day.
New region 13295 [N16W21] emerged on April 30 and was numbered by
SWPC 2 days later as the region began to decay.
New region 13296 [N17E63] rotated into view on May 1 and had tiny
spots early that day, then decayed after producing 2 C flares. New flux
emerged on May 2 and spots formed rapidly.
New region 13297 [N08E78] rotated into view with large spots and
could produce a major flare. C1 flares: C1.2 @ 08:42 UT
Spotted regions not observed (or interpreted
differently) by SWPC:
S8497 [S16W49] was quiet and stable.
S8506 [S14E17] reemerged with tiny spots.
S8515 [S11E29] was quiet and stable.
S8518 [S03W17] was quiet and stable.
New region S8523 [N06E26] emerged with a tiny spot.
New region S8524 [S07W09] emerged with a tiny spot.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C2.0 | 04:14 | 13293 | GOES18 | ||
| C4.3 | 04:42 | 13288 | GOES18 | ||
| C5.1 | 06:04 | 13296 | GOES18 | SWPC attributes this flare to a simultaneous event in AR 13288 | |
| C2.4 | 10:59 | 13288 | GOES18 | ||
| C3.3 | 17:33 | 13288 | GOES18 | ||
| C5.5 | 18:18 | 13288 | GOES18 | ||
| C3.5 | 18:59 | 13288 | GOES18 | ||
| C2.0 | 20:17 | 13288 | GOES18 | ||
| C2.1 | 21:18 | 13297 | GOES18 | ||
| C2.3 | 21:34 | 13297 | GOES18 | ||
| C2.2 | 22:57 | 13288 | GOES18 |
April 30 - May 2: 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) will be 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 | 3 | 2 | S17W75 | 0080 | HSX | CAO |
 |
 |
location: S17W77 |
| 13286 | 2023.04.21 2023.04.24 |
S11W70 |
 |
location: S11W65 | |||||||
| 13287 | 2023.04.23 2023.04.24 |
S25W49 | location: S27W39 | ||||||||
| 13288 | 2023.04.24 2023.04.25 |
8 | 16 | 11 | S23W68 | 0300 | EHI | FSO |
 |
 |
beta-gamma location: S22W72 |
| 13289 | 2023.04.25 2023.04.25 |
14 | 25 | 17 | N20W14 | 0150 | DSI | CAI |
 |
 |
location: N20W13 |
| 13291 | 2023.04.25 2023.04.26 |
2 | 2 | 2 | N08W76 | 0010 | AXX | AXX |
 |
 |
location: N07W74 |
| S8497 | 2023.04.25 | 1 | 1 | S16W49 | 0003 | AXX |
 |
 |
|||
| 13292 | 2023.04.25 2023.04.27 |
5 | 2 | N14W12 | 0010 | BXO |
 |
 |
location: N17W07 | ||
| S8500 | 2023.04.26 | N12W58 | |||||||||
| S8501 | 2023.04.27 | N21W45 | |||||||||
| S8504 | 2023.04.28 | N11W49 | |||||||||
| S8505 | 2023.04.29 | N19E37 |
 |
||||||||
| S8506 | 2023.04.29 | 2 | S14E17 | 0003 | BXO |
 |
|||||
| 13293 | 2023.04.30 2023.04.30 |
9 | 23 | 14 | N13E51 | 0250 | DHI | EAC |
 |
 |
beta-delta area: 0370 location: N13E50 |
| S8507 | 2023.04.30 | N20W23 | |||||||||
| 13295 | 2023.04.30 2023.05.02 |
2 | 8 | 2 | N15W21 | 0010 | AXX | CRO |
 |
 |
location: N16W21 area: 0025 |
| S8509 | 2023.04.30 | S25E52 | |||||||||
| S8510 | 2023.04.30 | S27W50 | |||||||||
| S8511 | 2023.04.30 | N09W17 | |||||||||
| S8512 | 2023.04.30 | S12W16 | |||||||||
| S8513 | 2023.04.30 | S31W22 | |||||||||
| S8514 | 2023.04.30 | N33E17 | |||||||||
| S8515 | 2023.05.01 | 2 | S11E29 | 0003 | AXX |
 |
 |
||||
| 13294 | 2023.05.01 2023.05.02 |
1 | 1 | 1 | S08E73 | 0100 | HSX | HSX |
 |
 |
area: 0220 location: S08E71 |
| S8517 | 2023.05.01 | N00E05 |
 |
||||||||
| S8518 | 2023.05.01 | 1 | 1 | S03W17 | 0002 | AXX |
 |
 |
|||
| S8519 | 2023.05.01 | N16W30 |
 |
||||||||
| S8520 | 2023.05.01 | S39W16 |
 |
||||||||
| 13296 | 2023.05.02 2023.05.02 |
5 | 16 | 8 | N15E64 | 0030 | CSO | DAI |
 |
was AR S8522 location: N17E63 area: 0090 |
|
| 13297 | 2023.05.02 2023.05.02 |
1 | 13 | 3 | N08E76 | 0180 | HAX | EKI |
 |
was AR S8521 location: N08E78 area: 0800 |
|
| S8523 | 2023.05.02 | 1 | 1 | N06E26 | 0003 | AXX |
 |
||||
| S8524 | 2023.05.02 | 1 | S07W09 | 0002 | AXX |
 |
|||||
| Total spot count: | 44 | 120 | 65 | ||||||||
| Sunspot number: | 134 | 280 | 195 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 89 | 163 | 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): | 147 | 154 | 156 | ||||||||
| 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 | 152.4 (1) | 7.1 (2A) / 110.5 (2B) / 145.4 (2C) | (129.3 projected, +5.6) | (8.3) | |
| 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.
