The geomagnetic field was at unsettled to extremely severe storm levels on May 10. A very strong solar wind shock was observed at SOHO at 16:38 UT with a sudden jump in solar wind speed from 470 to 770 km/sec - the total field of the interplanetary magnetic field peaked at 53 nT at 17:45 UT. A less obvious solar wind shock was observed at 21:39 UT at SOHO with solar wind speed peaking near 880 km/sec a little later - and the total field of the IMF peaked at a very high 74 nT at 23:06 UT. These solar wind shocks were related to halo CMEs observed on May 8 and 9 and caused the strongest geomagnetic disturbance in the last 20 years. The disturbance level at times exceeded the level required for Kp 9. The high latitude magnetometer at Andenes recorded quiet to severe storm levels. The above 10 MeV proton flux peaked at 207 pfu at 17:45 UT after the arrival of the first CME, then decreased to 10 pfu at the end of the day. The above 10, 50 and 100 MeV proton flux levels all increased quickly after the major X5.89 flare from AR S9676 peaking at 01:23 UT on May 11.
Solar flux density measured at 20h UT on 2.8 GHz was 223.4 - increasing 62.4 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 159.16. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 159.16 on November 10, 2023). The Potsdam WDC planetary A index was 117 (STAR Ap - based on the mean of three hour interval ap indices: 117.0). Three hour interval K indices: 33335889 (planetary), 33323779 (Boulder), 53124667 (Andenes).
The background x-ray flux is at the class C7 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 17 active regions using 2K resolution (SN: 438) and in 15 active regions using 1K resolution (SN: 266) SDO/HMI images.
Region 13664 [S17W57] was mostly quiet and
stable.
Region 13665 [S06W28] was quiet and stable.
Region 13666 [N07W79] was quiet and stable.
Region 13667 [N26W04] gained tiny trailing spots and was quiet.
Region 13669 [S10W21] reemerged with a tiny spot.
Region 13670 [N15E16] decayed slowly and quietly.
Region 13671 [N19E18] was quiet and stable.
Region 13672 [N18E46] developed further and has weak polarity
intermixing. A minor M class flare is possible.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S9676 [S19W48] is a huge, compact and extremely complex sunspot group
with many magnetic delta configurations. Further X class flaring is likely.
S9689 [S09E58] was quiet and stable.
S9690 [S15W16] was quiet and stable.
S9691 [S09E68] was quiet and stable.
S9692 [N23E18] emerged with tiny spots.
S9693 [N13W19] was quiet and stable.
S9695 [S21W38] was quiet and stable
New region S9697 [S22E38] emerged with tiny spots.
New region S9698 [S13E78] rotated into view with several spots.
Further M class flaring is possible.
Minor update posted at 17:30 UT: Today will become one of the most geomagnetically disturbed days in recorded history, and there's still a chance that the record could be broken. As I write this the average Ap for the day is 301. The most disturbed day in recorded history is November 13, 1960 when the average Ap ended at 280. The interplanetary magnetic field has weakened over the last hours and it is uncertain if the string of Kp 8 and 9s will be unbroken through the last 2 three hour intervals of the day. The second most disturbed day was on March 13, 1989 with an average Ap of 246.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| M1.0 | 00:04 | S9676 | GOES16 | ||
| M1.3 | 00:13 | S9698 | GOES16 | ||
| M1.4 | 00:17 | S9676 | GOES16 | ||
| M1.0 | 00:38 | S9676 | GOES16 | ||
| C6.8 | 01:48 | 13663 | GOES16 | ||
| C9.8 | 02:09 | S20W26 | S9676 | GOES16 | |
| C9.7 | 02:27 | 13663 | GOES16 | ||
| C5.9 | 02:54 | S9676 | GOES16 | ||
| C8.0 | 03:10 | 13663 | GOES16 | ||
| M1.4 | 03:29 | southeast limb | S9698 | GOES16 | incorrectly attributed to AR 13664 by SWPC |
| C7.2 | 04:06 | S9676 | GOES16 | ||
| C6.0 | 04:24 | 13663 | GOES16 | ||
| C7.4 | 04:42 | 13663 | GOES16 | ||
| C7.1 | 04:52 | S9676 | GOES16 | ||
| C5.8 | 05:15 | S9698 | GOES16 | ||
| C7.3 | 05:30 | 13663 | GOES16 | simultaneous flares in ARs S9676 and S9698 | |
| M1.3 | 06:24 | S9676 | GOES16 | ||
| X3.9/2B | 06:54 | S20W26 | S9676 | GOES16 | strong type II and moderate type IV radio
sweep full halo CME |
| M3.3 | 08:22 | S9676 | GOES16 | ||
| M1.7 | 09:19 | S9676 | GOES16 | ||
| M1.4 | 09:56 | S9676 | GOES16 | ||
| M2.2 | 10:14 | S9676 | GOES16 | ||
| M1.1 | 10:48 | 13663 | GOES16 | ||
| C9.2 | 11:31 | S9676 | GOES16 | ||
| M1.0 | 11:46 | S9676 | GOES16 | ||
| C6.3 | 12:34 | S9676 | GOES16 | ||
| C6.1 | 12:56 | 13670 | GOES16 | simultaneous flare in AR 13663 | |
| C7.5 | 13:49 | S9676 | GOES16 | ||
| M5.9/1N | 14:11 | S14W39 | S9676 | GOES16 | |
| C6.2 | 14:55 | S9698 | GOES16 | ||
| C7.3 | 15:55 | S9676 | GOES16 | ||
| C6.9 | 16:08 | S15W36 | S9676 | GOES16 | |
| C6.7 | 16:24 | S9676 | GOES16 | ||
| C8.2 | 16:58 | S9676 | GOES16 | ||
| M1.2 | 17:39 | S9676 | GOES16 | ||
| M1.2 | 17:56 | 13664 | GOES16 | ||
| C9.1 | 18:25 | S9676 | GOES16 | ||
| M1.1 | 18:32 | S9676 | GOES16 | ||
| M1.8 | 18:48 | S9676 | GOES16 | ||
| M2.0 | 19:05 | S9676 | GOES16 | ||
| M1.1 | 19:53 | S9676 | GOES16 | ||
| M1.9 | 20:03 | S9676 | GOES16 | ||
| M1.1 | 20:50 | S9676 | GOES16 | ||
| M3.8 | 21:08 | S9676 | GOES16 | ||
| M2.1 | 21:18 | S9676 | GOES16 | ||
| M2.4 | 21:25 | S9676 | GOES16 | ||
| M1.2 | 22:22 | S9676 | GOES16 | simultaneous flare in AR S9698 | |
| M1.3 | 22:47 | S9698 | GOES16 | ||
| M1.2 | 22:56 | behind northeast limb | GOES16 | ||
| M1.3 | 23:25 | S9676 | GOES16 | ||
| C8.9 | 23:48 | 13670 | GOES16 |
May 11: The X5 flare in AR
S9676 at 01:23 UT was associated with a bright halo CME.
May 10: The X3 flare in AR
S9676 at 06:54 UT was associated with another halo CME.
May 9: A full halo CME was observed following an X2 flare in AR
S9676.
[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 positive polarity northern hemisphere coronal hole (CH1221) was Earth facing on May 8-9.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle and high latitudes is very poor to useless. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be at minor to extremely severe storm levels on May 11-13 due to many inbound CMEs from flare activity in AR S9676.
| Coronal holes (1) | Coronal mass ejections (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 | ||||||||||
| 13661 | 2024.04.28 2024.04.29 |
N22W84 | |||||||||
| 13663 | 2024.04.29 2024.04.30 |
10 | N27W92 | 0300 | FKC |
 |
rotated out of view SWPC data is suspect, they have recorded 10 spots 3 days running in a decaying region rotating over the limb |
||||
| 13664 | 2024.04.30 2024.05.01 |
58 | 5 | 3 | S17W48 | 2400 | FKC | CAO |
 |
 |
area: 0180 location: S17W57 SWPC includes AR S9676 in this spot group |
| 13665 | 2024.05.01 2024.05.02 |
10 | 2 | S05W45 | 0020 | BXO |
 |
 |
location: S06W28 SWPC location is way off |
||
| 13666 | 2024.05.02 2024.05.03 |
1 | 2 | 1 | N08W80 | 0050 | HSX | HSX |
 |
 |
area: 0090 location: N07W79 |
| 13669 | 2024.05.02 2024.05.05 |
1 | 1 | S09W27 | 0003 | AXX |
 |
location: S10W21 |
|||
| 13668 | 2024.05.03 2024.05.05 |
S15W41 | merged with AR S9676 on May 9 | ||||||||
| S9670 | 2024.05.03 | N04W37 | |||||||||
| 13667 | 2024.05.03 2024.05.04 |
1 | 8 | 4 | N28W05 | 0040 | HSX | CHO |
 |
 |
area: 0270 location: N26W04 |
| S9672 | 2024.05.03 | S33W34 | |||||||||
| S9676 | 2024.05.05 | 142 | 61 | S19W48 | 3130 | FKC |
 |
 |
gamma-delta | ||
| 13670 | 2024.05.05 2024.05.06 |
6 | 18 | 9 | N17E14 | 0050 | HAX | CRI |
 |
 |
location: N15E16 |
| S9679 | 2024.05.06 | N15W20 | |||||||||
| 13671 | 2024.05.06 2024.05.09 |
1 | 11 | 6 | N19E17 | 0030 | HSX | CAI |
 |
 |
beta-gamma location: N19E18 |
| S9682 | 2024.05.07 | N15W30 | |||||||||
| S9683 | 2024.05.07 | S26W21 | |||||||||
| S9684 | 2024.05.07 | S24E11 | |||||||||
| 13672 | 2024.05.08 2024.05.09 |
9 | 27 | 10 | N18E45 | 0140 | CAI | DAI |
 |
 |
beta-gamma location: N18E46 area: 0200 |
| S9687 | 2024.05.08 | S07W11 | |||||||||
| S9689 | 2024.05.08 | 5 | 1 | S09E58 | 0010 | BXO |
 |
 |
|||
| S9690 | 2024.05.09 | 2 | 1 | S15W16 | 0005 | BXO |
 |
 |
|||
| S9691 | 2024.05.09 | 1 | 1 | S09E68 | 0080 | HAX |
 |
 |
|||
| S9692 | 2024.05.09 | 16 | 6 | N23E18 | 0050 | CRI |
 |
 |
|||
| S9693 | 2024.05.09 | 2 | N13W19 | 0002 | BXO |
 |
 |
||||
| S9694 | 2024.05.09 | S04E26 |
 |
||||||||
| S9695 | 2024.05.09 | 1 | S21W38 | 0001 | AXX |
 |
 |
||||
| S9696 | 2024.05.09 | S30W23 |
 |
||||||||
| S9697 | 2024.05.10 | 5 | 3 | S22E38 | 0010 | CRO |
 |
||||
| S9698 | 2024.05.10 | 12 | 7 | S13E78 | 0200 | CAO |
 |
||||
| Total spot count: | 86 | 268 | 116 | ||||||||
| Sunspot number: | 156 | 438 | 266 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 131 | 327 | 175 | (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): | 172 | 241 | 213 | ||||||||
| 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 |
| 2022.10 | 133.5 | 132.7 | 95.5 | 98.9 (+2.4) | 11.16 |
| 2022.11 | 123.4 | 120.7 | 80.5 | 101.2 (+2.3) | 9.33 |
| 2022.12 | 147.9 | 143.4 | 112.8 | 106.7 (+5.5) | 10.99 |
| 2023.01 | 182.4 | 176.6 | 144.4 | 113.3 (+6.6) | 8.73 |
| 2023.02 | 167.2 | 163.2 | 111.3 | 117.8 (+3.5) | 14.48 (current SC25 peak) |
| 2023.03 | 157.2 | 155.6 | 123.3 | 121.1 (+3.3) | 14.42 |
| 2023.04 | 145.4 | 146.4 | 97.6 | 122.9 (+1.8) | 13.40 |
| 2023.05 | 155.6 | 159.2 | 137.4 | 124.2 (+1.3) | 10.67 |
| 2023.06 | 161.7 | 166.8 | 160.5 | 125.3 (+1.1) (SC25 solar max candidate) |
8.95 |
| 2023.07 | 176.4 | 182.2 | 160.0 | 124.4 (-0.9) | 8.15 |
| 2023.08 | 153.7 | 157.6 | 114.8 | 124.1 (-0.3) | 7.19 |
| 2023.09 | 154.4 | 156.0 | 134.2 | 123.9 (-0.2) | 14.26 |
| 2023.10 | 142.8 | 141.9 | 99.4 | 124.8 (+0.9) | 8.16 |
| 2023.11 | 153.5 | 150.2 | 105.4 | (125.2 projected, +0.4) | 12.20 |
| 2023.12 | 151.1 | 146.4 | 114.2 | (121.9 projected, -3.3) | 9.60 |
| 2024.01 | 164.6 | 159.3 | 123.0 | (118.5 projected, -3.4) | 5.46 |
| 2024.02 | 172.5 | 168.3 | 124.7 | (117.7 projected, -0.8) | 5.31 |
| 2024.03 | 154.4 | 152.9 | 104.9 | (117.1 projected, -0.6) | 11.03 |
| 2024.04 | 161.3 | 162.6 | 136.5 | (117.1 projected, -0.0) | 9.69 |
| 2024.05 | 183.6 (1) | 45.1 (2A) / 139.8 (2B) / 195.0 (2C) | (118.3 projected, +1.2) | (22.4) | |
| 2024.06 | (117.4 projected, -0.9) | ||||
| 2024.07 | (115.7 projected, -1.7) | ||||
| 2024.08 | (113.8 projected, -1.9) | ||||
| 2024.09 | (112.5 projected, -1.3) | ||||
| 2024.10 | (111.1 projected, -1.4) | ||||
| 2024.11 | (108.6 projected, -2.5) | ||||
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: WDC-SILSO, Royal Observatory
Of Belgium, Brussels
The big increase in sunspot counts during the April 14-27 interval caused a major uptick in the smoothed SNs and solar flux. It's not yet clear when the next peak will be, anytime between October 28 and December 20, 2023 looks possible. The 365d smoothed solar flux exceeded the June 27 peak on October 28, while the 365d smoothed ISN and NOAA SN both exceeded the June 2023 peak in late October 2023. It should be noted that the current peak using 13-month smoothing is still in June 2023.
--------------------------------------------------------------------------------------
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.
