The geomagnetic field was quiet to minor storm on May 10 under the influence of CME effects. Solar wind speed at SOHO ranged between 550 and 720 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 170.1 - increasing 10.6 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 140.96. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 24 (STAR Ap - based on the mean of three hour interval ap indices: 23.9). Three hour interval K indices: 45245322 (planetary), 35334322 (Boulder), 54244444 (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 14 active regions using 2K resolution (SN: 327) and in 12 active regions using 1K resolution (SN: 220) SDO/HMI images.
Region 13293 [N13W57] decayed slowly and
produced a couple of C flares. The trailing spot section is close to the leader spots of
AR 13296.
Region 13294 [S07W35] gained several tiny spots and was quiet.
Region 13296 [N16W49] decayed losing most of the magnetic deltas. M
class flaring is still likely. C1 flares: C1.4 @ 08:09 UT
Region 13297 [N09W31] decayed slowly and was mostly quiet. C1 flares:
C1.6 @ 06:39 UT
Region 13299 [S07W11] decayed slowly and quietly.
Region 13300 [N10W12] decayed slowly and
quietly.
Region 13301 [N12E56] was quiet and stable.
Region 13302 [N19E61] was quiet and stable.
Region 13303 [S10E42] decayed slowly and quietly.
Spotted regions not observed (or interpreted
differently) by SWPC:
S8541 [S22W10] was quiet and stable.
S8544 [N22E36] developed slowly and quietly.
New region S8551 [N12E34] emerged with tiny spots.
New region S8552 [S19E20] emerged with tiny spots.
New region S8553 [N26E03] emerged with tiny spots.
An active region behind the southwest limb produced a C1.6 flare at 17:43 UT.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C3.8 | 01:42 | 13296 | GOES16 | ||
| C2.1 | 03:16 | 13296 | GOES16 | ||
| C4.0 | 04:12 | 13296 | GOES16 | ||
| C3.9 | 04:20 | 13296 | GOES16 | ||
| C2.1 | 11:23 | 13296 | GOES16 | ||
| C2.1 | 13:02 | 13297 | GOES16 | ||
| M2.2/1B | 14:21 | 13296 | GOES16 | ||
| C5.7 | 15:00 | 13296 | GOES16 | ||
| C4.1 | 15:14 | 13297 | GOES16 | ||
| C2.6 | 16:04 | 13296 | GOES16 | ||
| C2.9 | 18:42 | 13293 | GOES16 | ||
| C5.8 | 19:35 | southwest limb | GOES16 | ||
| C4.3 | 19:59 | 13296 | GOES16 | ||
| C2.7 | 21:18 | 13296 | GOES16 | ||
| C4.5 | 22:16 | 13293 | GOES16 |
May 8, 10: No obviously Earth directed CMEs were
observed.
May 9: A fast full halo CME was observed after the M4.2 flare in AR
13296 at 18:58 UT. The CME is expected to reach Earth on May 11.
[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]
An elongated northern hemisphere coronal hole (CH1146) will be Earth facing on May 8-11, but may be too far to the north to cause a geomagnetic disturbance. A southern hemisphere coronal hole (CH1147) will rotate across the central meridian on May 11.
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.
Quiet to major storm conditions are likely on May 11 due to CME effects. The May 9 CME is expected to arrive during the latter half of the day and cause unsettled to severe storm conditions on May 12. Quiet to active is likely on May 13.
| 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 | ||||||||||
| 13293 | 2023.04.30 2023.04.30 |
4 | 11 | 4 | N10W60 | 0010 | BXO | EAO |
 |
 |
location: N13W57 area: 0050 |
| S8509 | 2023.04.30 | S25W52 | |||||||||
| 13294 | 2023.05.01 2023.05.02 |
6 | 21 | 8 | S07W33 | 0130 | CSO | CSO |
 |
 |
area: 0230 location: S07W35 |
| 13296 | 2023.05.02 2023.05.02 |
28 | 34 | 20 | N15W49 | 0290 | EKC | EAC |
 |
 |
beta-gamma-delta area: 0450 location: N16W49 |
| 13297 | 2023.05.02 2023.05.02 |
20 | 40 | 21 | N10W29 | 0400 | EKI | EKI |
 |
 |
beta-gamma location: N09W31 |
| 13298 | 2023.05.03 2023.05.04 |
S16W50 | location: S15W44 | ||||||||
| 13299 | 2023.05.03 2023.05.04 |
1 | S08W13 | 0002 | AXX |
 |
 |
location: S07W11 |
|||
| S8528 | 2023.05.04 | S05W10 |
 |
||||||||
| S8529 | 2023.05.04 | S26E04 |
 |
||||||||
| S8530 | 2023.05.04 | S19W57 | |||||||||
| S8533 | 2023.05.06 | N17W36 | |||||||||
| 13300 | 2023.05.06 2023.05.09 |
6 | 15 | 11 | N10W13 | 0050 | DAO | DAO |
 |
 |
area: 0080 location: N10W12 |
| S8537 | 2023.05.06 | N29W16 | |||||||||
| 13303 | 2023.05.07 2023.05.09 |
4 | 9 | 6 | S10E41 | 0030 | CRO | CRO |
 |
 |
location: S10E42 |
| S8541 | 2023.05.07 | 11 | 5 | S22W10 | 0020 | BXO |
 |
 |
|||
| 13301 | 2023.05.08 2023.05.09 |
2 | 11 | 5 | N11E54 | 0120 | HSX | CAO |
 |
 |
area: 0160 location: N12E56 |
| S8543 | 2023.05.08 | N25W08 | |||||||||
| S8544 | 2023.05.08 | 15 | 9 | N22E36 | 0040 | DRI |
 |
 |
|||
| 13302 | 2023.05.08 2023.05.09 |
4 | 12 | 6 | N18E59 | 0030 | CRO | CSO |
 |
 |
area: 0140 |
| S8546 | 2023.05.08 | S05W55 | |||||||||
| S8549 | 2023.05.09 | S18E29 |
 |
||||||||
| S8550 | 2023.05.09 | S28W22 |
 |
||||||||
| S8551 | 2023.05.10 | 3 | 3 | N12E34 | 0010 | BXO |
 |
||||
| S8552 | 2023.05.10 | 2 | 2 | S19E20 | 0005 | BXO |
 |
||||
| S8553 | 2023.05.10 | 2 | N26E03 | 0004 | BXO |
 |
|||||
| Total spot count: | 74 | 187 | 100 | ||||||||
| Sunspot number: | 154 | 327 | 220 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 115 | 233 | 146 | (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): | 169 | 180 | 176 | ||||||||
| 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 | 160.9 (1) | 38.3 (2A) / 119.7 (2B) / 157.4 (2C) | (129.3 projected, +5.6) | (10.8) | |
| 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.
