The geomagnetic field was quiet to minor storm on May 8 under the influence of CME effects and a high speed stream from CH1145 during the first half of the day. An additional disturbance, likely the May 5 CME, was observed reaching SOHO at 13:13 UT with a notable increase in solar wind density. Geomagnetic field activity increased from quiet levels to unsettled to active. Solar wind speed at SOHO ranged between 442 and 571 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 171.9 - increasing 28.5 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 140.65. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 16 (STAR Ap - based on the mean of three hour interval ap indices: 16.4). Three hour interval K indices: 52213434 (planetary), 53313322 (Boulder), 62225546 (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 15 active regions using 2K resolution (SN: 361) and in 11 active regions using 1K resolution (SN: 212) SDO/HMI images.
Region 13293 [N11W31] decayed slowly and
quietly.
Region 13294 [S07W09] was mostly quiet and stable.
Region 13296 [N15W21] developed significantly and gained a magnetic
delta. Major flares are possible, the probability of an X class flare is
increasing. The region has inversed polarities. The region was the source of
a major M6.5 flare at 03:54 UT on May 9. C1 flares: C1.9 @ 12:02, C1.8 @
23:14 UT
Region 13297 [N09W03] gained a magnetic delta and could produce a
major flare. C1 flares: C1.7 @ 12:35, C1.9 @ 13:22 UT
Region 13299 [S08E13] was quiet and stable.
Spotted regions not observed (or interpreted
differently) by SWPC:
S8528 [S05E18] decayed slowly and quietly.
S8529 [S24E29] decayed slowly and quietly.
S8536 [N11E13] reemerged with many spots.
S8540 [S10E70] was quiet and stable.
S8541 [S23E15] was quiet and stable.
New region S8542 [N12E82] rotated into view with a mature spot.
New region S8543 [N25E18] was observed with tiny spots in an old
plage area.
New region S8544 [N22E62] emerged with a tiny spot.
New region S8545 [N18E87] rotated partly into view. C1 flares: C1.9 @
18:14 UT
New region S8546 [S05W29] emerged with a tiny spot.
A proton event (associated with the M1 LDE in AR 13296 late on May 7) is in progress and has so far peaked at 38.4 pfu at 01:50 UT on May 9.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C7.9 | 02:23 | 13296 | GOES16 | ||
| C3.1 | 05:24 | 13297 | GOES16 | ||
| C3.2 | 05:37 | 13296 | GOES16 | ||
| C3.6 | 06:46 | 13296 | GOES16 | ||
| C3.0 | 08:25 | 13296 | GOES16 | ||
| C3.6 | 08:38 | 13296 | GOES16 | moderate type II radio sweep | |
| C4.6 | 10:00 | 13296 | GOES16 | ||
| C2.2 | 11:05 | 13296 | GOES16 | ||
| C2.0 | 11:30 | 13296 | GOES16 | ||
| C9.6/1B | 14:21 | 13296 | GOES16 | ||
| C2.1 | 15:15 | 13296 | GOES16 | ||
| C2.6 | 15:34 | 13296 | GOES16 | ||
| C3.0 | 16:10 | 13296 | GOES16 | ||
| M2.3 | 20:24 | 13296 | GOES16 | ||
| C9.1 | 20:42 | 13296 | GOES16 | ||
| C4.6 | 22:04 | 13294 | GOES16 | ||
| C2.6 | 22:38 | 13296 | GOES16 |
May 7: Halo CMEs were observed after the M1
long duration events in AR 13296 towards the end of the day. The CMEs could
reach Earth on May 10.
May 6, 8: 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 northern hemisphere coronal hole (CH1146) will likely become Earth facing on May 8-9, but may be too far to the north to cause a geomagnetic disturbance.
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 9 due to CME effects. The May 7 CME is expected to arrive on May 10 and cause unsettled to major storm conditions until May 12 with isolated severe storm intervals possible.
| 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 | ||||||||||
| S8505 | 2023.04.29 | N19W42 |
 |
||||||||
| S8506 | 2023.04.29 | S10W52 | |||||||||
| 13293 | 2023.04.30 2023.04.30 |
8 | 34 | 17 | N10W33 | 0030 | CRO | ERI |
 |
 |
location: N11W31 area: 0070 |
| S8509 | 2023.04.30 | S25W26 | |||||||||
| S8515 | 2023.05.01 | S11W49 | |||||||||
| 13294 | 2023.05.01 2023.05.02 |
1 | 9 | 3 | S08W08 | 0130 | HSX | CSO |
 |
 |
area: 0230 location: S07W09 |
| 13296 | 2023.05.02 2023.05.02 |
16 | 41 | 26 | N16W20 | 0300 | EKC | DKC |
 |
 |
beta-gamma-delta area: 0520 reversed polarities |
| 13297 | 2023.05.02 2023.05.02 |
21 | 68 | 31 | N08W03 | 0510 | EKC | EKC |
 |
 |
beta-gamma-delta area: 0570 |
| S8523 | 2023.05.02 | N06W52 | |||||||||
| 13298 | 2023.05.03 2023.05.04 |
S16W21 | location: S15W18 | ||||||||
| 13299 | 2023.05.03 2023.05.04 |
5 | 11 | 6 | S07E15 | 0010 | BXO | DRO |
 |
 |
location: S08E13 area: 0030 |
| S8528 | 2023.05.04 | 6 | 1 | S05E18 | 0010 | BXO |
 |
 |
|||
| S8529 | 2023.05.04 | 6 | 1 | S24E29 | 0008 | BXO |
 |
 |
|||
| S8530 | 2023.05.04 | S19W31 |
 |
||||||||
| S8532 | 2023.05.05 | S27W50 | |||||||||
| S8533 | 2023.05.06 | N17E10 |
 |
||||||||
| S8535 | 2023.05.06 | N05W57 | |||||||||
| S8536 | 2023.05.06 | 18 | 11 | N11E13 | 0070 | DRI |
 |
||||
| S8537 | 2023.05.06 | N29E10 | |||||||||
| S8538 | 2023.05.06 | S30W44 | |||||||||
| S8540 | 2023.05.07 | 1 | S10E70 | 0002 | AXX |
 |
 |
||||
| S8541 | 2023.05.07 | 10 | 4 | S23E15 | 0020 | BXO |
 |
 |
|||
| S8542 | 2023.05.08 | 1 | 1 | N12E82 | 0200 | HSX |
 |
||||
| S8543 | 2023.05.08 | 3 | 1 | N25E18 | 0007 | AXX |
 |
||||
| S8544 | 2023.05.08 | 1 | N22E62 | 0001 | AXX |
 |
|||||
| S8545 | 2023.05.08 | 1 | N18E87 | 0100 | HSX |
 |
|||||
| S8546 | 2023.05.08 | 1 | S05W29 | 0002 | AXX |
 |
|||||
| Total spot count: | 51 | 211 | 102 | ||||||||
| Sunspot number: | 101 | 361 | 212 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 79 | 255 | 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): | 111 | 199 | 170 | ||||||||
| 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 | 158.2 (1) | 28.8 (2A) / 111.5 (2B) / 154.7 (2C) | (129.3 projected, +5.6) | (10.6) | |
| 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.
