The geomagnetic field was quiet to unsettled on May 11. Solar wind speed at SOHO ranged between 478 and 675 km/sec. The high latitude magnetometer at Andenes recorded quiet to active levels. A relatively weak solar wind shock was observed at 05:49 UT at DSCOVR on May 12 as the May 9 CME arrived later than expected. The IMF has been mostly northwards since the arrival of the shock resulting in only a minor geomagnetic disturbance so far.
Solar flux density measured at 20h UT on 2.8 GHz was 163.4 - decreasing 7.9 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 141.06. 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: 7.9). Three hour interval K indices: 33211123 (planetary), 23222323 (Boulder), 44123234 (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 13 active regions using 2K resolution (SN: 318) and in 13 active regions using 1K resolution (SN: 227) SDO/HMI images.
Region 13293 [N14W72] gained some spots in a
northwestern section and was mostly quiet. The trailing spot section is close to the leader spots of
AR 13296. C1 flares: C1.9 @ 16:34 UT
Region 13294 [S07W48] developed a few small and tiny spots near the
largest spot and produced several flares.
Region 13296 [N15W62] decayed slowly and continued to produce mostly
C flares. C1 flares: C1.8 @ 05:25, C1.8 @ 19:59 UT
Region 13297 [N09W45] decayed slowly and quietly.
Region 13299 [S07W26] was quiet and stable.
Region 13300 [N10W25] was mostly quiet and stable.
Region 13301 [N12E44] gained trailing spots and was quiet There is
some polarity intermixing in the trailing spot section.
Region 13302 [N19E48] was mostly quiet and stable.
Region 13303 [S10E30] decayed slowly and quietly.
New region 13304 [N22E23] emerged on May 8 and was numbered by SWPC 3
days later as the region continued to gain spots.
Spotted regions not observed (or interpreted
differently) by SWPC:
S8528 [S07W16] reemerged with tiny spots.
S8541 [S22W23] was quiet and stable.
S8551 [N12E22] was quiet and stable.
A region behind the southwest limb produced a C1.6 flare at 07:26 and a C1.8 flare at 11:08 UT.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C2.9 | 00:30 | southwest limb | GOES16 | incorrectly attributed to AR 13293 by SWPC | |
| C3.9 | 00:52 | 13296 | GOES16 | ||
| C4.1 | 01:09 | 13294 | GOES16 | ||
| C2.5 | 02:58 | 13293 | GOES16 | ||
| C2.3 | 03:14 | southwest limb | GOES16 | ||
| C2.5 | 03:35 | southwest limb | GOES16 | ||
| C2.0 | 04:12 | 13302 | GOES16 | ||
| C2.1 | 04:20 | 13293 | GOES16 | ||
| C3.2 | 04:39 | 13296 | GOES16 | ||
| C2.0 | 05:50 | 13300 | GOES16 | ||
| C2.0 | 06:12 | southwest limb | GOES16 | ||
| M2.2/1N | 09:01 | S06W41 | 13294 | GOES16 | moderate type II radio sweep CME? |
| C3.1 | 09:22 | 13293 | GOES16 | ||
| C2.2 | 12:23 | 13302 | GOES16 | ||
| C3.0 | 13:06 | N13W54 | 13296 | GOES16 | |
| C6.2/1F | 14:02 | N14W53 | 13296 | GOES16 | |
| M1.8/1N | 18:29 | S05W44 | 13294 | GOES16 | simultaneous flare in AR 13297 |
| C3.4 | 20:18 | N13W61 | 13296 | GOES16 |
May 11: Several CMEs were observed during the
day. A faint halo CME may have been associated with the M2 flare in AR 13294
at 09:01 UT.
May 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 reached Earth on May 12.
[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) was 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) rotated 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 active conditions are likely on May 12-13 due to CME effects. Quiet conditions are expected on May 14, however, should the May 11 CME arrive, quiet to active conditions will be likely.
| 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 |
1 | 10 | 6 | N10W74 | 0010 | AXX | EAO |
 |
 |
location: N14W72 area: 0050 |
| 13294 | 2023.05.01 2023.05.02 |
6 | 9 | 5 | S07W47 | 0130 | CSO | DSO |
 |
 |
area: 0220 location: S07W48 |
| 13296 | 2023.05.02 2023.05.02 |
16 | 28 | 17 | N15W63 | 0260 | EKC | EAC |
 |
 |
beta-gamma area: 0320 location: N15W62 |
| 13297 | 2023.05.02 2023.05.02 |
14 | 35 | 13 | N10W43 | 0320 | EKI | EAO |
 |
 |
beta-gamma location: N09W45 |
| 13298 | 2023.05.03 2023.05.04 |
S16W64 | location: S15W57 | ||||||||
| 13299 | 2023.05.03 2023.05.04 |
1 | 1 | S08W27 | 0002 | AXX |
 |
 |
location: S07W26 |
||
| S8528 | 2023.05.04 | 2 | 1 | S07W16 | 0006 | BXO |
 |
||||
| S8529 | 2023.05.04 | S26W09 | |||||||||
| S8533 | 2023.05.06 | N17W49 | |||||||||
| 13300 | 2023.05.06 2023.05.09 |
4 | 12 | 10 | N10W27 | 0050 | DAO | DRO |
 |
 |
location: N10W25 |
| S8537 | 2023.05.06 | N29W29 | |||||||||
| 13303 | 2023.05.07 2023.05.09 |
4 | 11 | 6 | S10E27 | 0010 | BXO | BXO |
 |
 |
location: S10E30 area: 0020 |
| S8541 | 2023.05.07 | 15 | 5 | S22W23 | 0020 | BXO |
 |
 |
|||
| 13301 | 2023.05.08 2023.05.09 |
3 | 20 | 11 | N12E40 | 0120 | HSX | EAO |
 |
 |
area: 0180 location: N12E44 |
| S8543 | 2023.05.08 | N25W21 | |||||||||
| 13304 | 2023.05.08 2023.05.11 |
8 | 27 | 12 | N22E21 | 0010 | BXO | DRI |
 |
 |
area: 0060 |
| 13302 | 2023.05.08 2023.05.09 |
6 | 16 | 8 | N18E45 | 0080 | CSO | DSO |
 |
 |
area: 0140 |
| S8549 | 2023.05.09 | S18E16 | |||||||||
| S8550 | 2023.05.09 | S28W35 | |||||||||
| S8551 | 2023.05.10 | 2 | 2 | N12E22 | 0006 | BXO |
 |
 |
|||
| S8552 | 2023.05.10 | S19E07 |
 |
||||||||
| S8553 | 2023.05.10 | N26W10 |
 |
||||||||
| Total spot count: | 62 | 188 | 97 | ||||||||
| Sunspot number: | 152 | 318 | 227 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 102 | 224 | 133 | (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): | 167 | 175 | 182 | ||||||||
| 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 | 161.1 (1) | 43.5 (2A) / 122.6 (2B) / 158.1 (2C) | (129.3 projected, +5.6) | (11.8) | |
| 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.
