The geomagnetic field was at quiet levels on May 9. The high latitude magnetometer at Andenes recorded quiet to unsettled levels. The above 10 MeV proton flux was at 1.0 pfu at the end of the day, slowly increasing after flares early in the day.
Solar flux density measured at 20h UT on 2.8 GHz was 233.2 - increasing 81.7 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 159.00. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 158.82 on November 8, 2023). The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 5.1). Three hour interval K indices: 12111122 (planetary), 12022332 (Boulder), 03122222 (Andenes).
The background x-ray flux is at the class C6 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 18 active regions using 2K resolution (SN: 429) and in 14 active regions using 1K resolution (SN: 262) SDO/HMI images.
Region 13663 [N25W78] rotated partly out of
view and decayed slowly.
Region 13664 [S17W44] lost the trailing spots due to further growth
in huge AR S9676.
Region 13665 [S07W13] was quiet and stable.
Region 13666 [N07W65] was quiet and stable.
Region 13667 [N26E08] was quiet and stable.
Region 13670 [N15E29] developed slowly and quietly.
New region 13671 [N20E30] emerged on May 6 and was numbered by SWPC 3
days later.
New region 13672 [N18E59] emerged on May 8 and received its NOAA
number the following day.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S9676 [S20W33] merged with AR 13668 and the trailing spots of AR
13664. This spot group is one of the largest of the last solar cycles and
certainly one of the most complex with many strong magnetic delta
configurations. An X10+ flare is possible. Very frequent flaring continued
with a slight reduction in the background xray flux.
S9685 [S23W57] decayed slowly and quietly.
S9689 [S09E70] was quiet and stable.
New region S9690 [S18W02] emerged with tiny spots.
New region S9691 [S09E81] rotated into view with a single spot.
New region S9692 [N27E31] emerged with tiny spots.
New region S9693 [N12W10] was observed with tiny spots in an
old plage area.
New region S9694 [S04E39] emerged with a tiny spot.
New region S9695 [S23W19] emerged with a tiny spot.
New region S9696 [S30W10] emerged with a tiny
spot.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| M1.6 | 01:02 | S9676 | GOES16 | ||
| M1.8 | 01:14 | S9676 | GOES16 | ||
| M1.8 | 01:40 | S9676 | GOES16 | ||
| M4.0/1B | 03:17 | S19W24 | S9676 | GOES16 | |
| M4.5 | 03:32 | S9676 | GOES16 | ||
| M1.2 | 04:26 | S9676 | GOES16 | ||
| M1.7 | 04:49 | S9676 | GOES16 | ||
| M1.2 | 05:38 | S9676 | GOES16 | ||
| M2.3 | 06:13 | S9676 | GOES16 | ||
| M2.4 | 06:27 | S9676 | GOES16 | ||
| M1.2 | 07:07 | 13663 | GOES16 | ||
| C9.5 | 07:37 | S9676 | GOES16 | ||
| M1.1 | 07:46 | 13663 | GOES16 | simultaneous flare in AR S9676 | |
| M1.2 | 07:59 | S9676 | GOES16 | ||
| M1.1 | 08:12 | S9676 | GOES16 | ||
| M1.1 | 08:25 | S9676 | GOES16 | ||
| M2.1 | 08:40 | 13663 | GOES16 | simultaneous flare in AR S9676 | |
| X2.2/3B | 09:13 | S20W36 | S9676 | GOES16 | full halo CME |
| M2.9 | 10:39 | S9676 | GOES16 | ||
| M1.6 | 11:36 | S9676 | GOES16 | ||
| M3.1 | 11:56 | 13664 | GOES16 | ||
| M3.0 | 12:12 | 13663 | GOES16 | simultaneous flare in AR 13664 | |
| M3.7 | 13:23 | 13664 | GOES16 | ||
| C9.8 | 13:56 | S9676 | GOES16 | ||
| M1.0 | 14:05 | 13664 | GOES16 | ||
| C7.8 | 14:23 | S9676 | GOES16 | ||
| C7.3 | 14:33 | S9676 | GOES16 | ||
| C6.0 | 15:21 | 13663 | GOES16 | ||
| C5.8 | 15:45 | S9676 | GOES16 | ||
| C8.1 | 17:18 | 13663 | GOES16 | ||
| X1.1/2B | 17:44 | S9676 | GOES16 | strong type II and moderate tyoe IV radio sweeps | |
| M1.2 | 19:21 | S9676 | GOES16 | ||
| C7.0 | 20:54 | 13664 | GOES16 | ||
| C7.8 | 21:04 | 13664 | GOES16 | ||
| M1.0 | 21:21 | 13663 | GOES16 | ||
| C7.8 | 21:49 | S9676 | GOES16 | ||
| C7.7 | 21:57 | 13664 | GOES16 | ||
| M1.0 | 22:15 | 13663 | GOES16 | simultaneous flare in AR S9676 | |
| M1.3 | 22:30 | 13663 | GOES16 | ||
| M2.7 | 22:41 | 13664 | GOES16 | simultaneous flare in AR 13663 | |
| M1.0 | 22:56 | S9676 | GOES16 | ||
| M1.2 | 23:08 | southeast limb | S9691 | GOES16 | |
| M1.6 | 23:51 | S9676 | GOES16 |
Minor update posted at 18:45 UT: A very strong solar wind shock was recorded at ACE at 16:37 UT, the arrival of one or two CMEs from May 8. Severe to very severe geomagnetic storming has been observed since the arrival of the solar storm. A strong increase in the above 10 MeV proton flux was observed as the CMEs arrived, a peak value of 207 pfu was recorded at 17:45 UT.
May 10: The X3.98 flare in AR
S9676 at 06:54 UT was likely associated with another CME, however, awaiting
the availability of LASCO imagery to determine if that's the case.
May 9: A full halo CME was observed following an X2 flare in AR
S9676.
May 8: A full halo CME was observed after an X1 flare in AR S9676
peaking at 05:09 UT on May 8. The CME could reach Earth after noon on May 10 or early on
May 11. Another full halo CME was observed after an M8.9 flare at 12:04 UT.
Finally a third full halo CME was observed after an X1 flare and an M9.8
flare late in the day. The latter CME is the most significant. Expect minor
to very severe geomagnetic storm conditions from the impact of the first two
CMEs until May 12.
May 7: 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 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 poor. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet to active on May 10. Active to very severe geomagnetic storm conditions are possible from late on May 10 until May 13 due to multiple full halo CMEs. Although effects from CH1221 are possible on May 11-12, CME effects are likely to be dominant.
| 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 |
N22W70 | |||||||||
| 13663 | 2024.04.29 2024.04.30 |
10 | 9 | 4 | N25W83 | 0300 | FKC | CAO |
 |
 |
area: 0150 location N25W78 |
| 13664 | 2024.04.30 2024.05.01 |
81 | 10 | 6 | S19W34 | 1090 | FKC | CAO |
 |
 |
area: 0200 location: S17W44 SWPC includes AR S9676 in this spot group |
| S9660 | 2024.04.30 | N09W50 |
 |
||||||||
| 13665 | 2024.05.01 2024.05.02 |
12 | 4 | S05W30 | 0020 | BXO |
 |
 |
location: S07W13 SWPC location is way off |
||
| 13666 | 2024.05.02 2024.05.03 |
1 | 5 | 2 | N08W65 | 0050 | HSX | CAO |
 |
 |
area: 0080 |
| 13669 | 2024.05.02 2024.05.05 |
S09W13 |
location: S09W09 |
||||||||
| 13668 | 2024.05.03 2024.05.05 |
S15W27 |
 |
merged with AR S9676 on May 9 | |||||||
| S9670 | 2024.05.03 | N04W24 | |||||||||
| 13667 | 2024.05.03 2024.05.04 |
1 | 4 | 3 | N26E08 | 0130 | HSX | HHX |
 |
 |
area: 0280 |
| S9672 | 2024.05.03 | S33W21 | |||||||||
| S9675 | 2024.05.05 | S10W56 | |||||||||
| S9676 | 2024.05.05 | 145 | 75 | S20W33 | 3060 | FKC |
 |
 |
gamma-delta | ||
| 13670 | 2024.05.05 2024.05.06 |
1 | 11 | 4 | N16E31 | 0040 | HSX | CAO |
 |
 |
area: 0080 location: N15E29 |
| S9679 | 2024.05.06 | N15W07 | |||||||||
| 13671 | 2024.05.06 2024.05.09 |
1 | 13 | 7 | N20E33 | 0040 | HAX | CAO |
 |
 |
location: N20E30 |
| S9681 | 2024.05.06 | S31W57 | |||||||||
| S9682 | 2024.05.07 | N15W17 | |||||||||
| S9683 | 2024.05.07 | S26W08 | |||||||||
| S9684 | 2024.05.07 | S24E24 | |||||||||
| S9685 | 2024.05.08 | 1 | S23W57 | 0001 | AXX |
 |
 |
||||
| 13672 | 2024.05.08 2024.05.09 |
5 | 16 | 7 | N18E58 | 0030 | CRO | DAO |
 |
 |
location: N18E59 area: 0200 |
| S9687 | 2024.05.08 | S07E02 |
 |
||||||||
| S9689 | 2024.05.08 | 7 | 4 | S09E70 | 0015 | CRO |
 |
 |
|||
| S9690 | 2024.05.09 | 3 | 2 | S18W02 | 0006 | BXO |
 |
||||
| S9691 | 2024.05.09 | 1 | 1 | S09E81 | 0080 | HSX |
 |
||||
| S9692 | 2024.05.09 | 3 | 2 | N27E31 | 0008 | CRO |
 |
||||
| S9693 | 2024.05.09 | 5 | N12W10 | 0008 | BXO |
 |
|||||
| S9694 | 2024.05.09 | 1 | S04E39 | 0001 | AXX |
 |
|||||
| S9695 | 2024.05.09 | 2 | S23W19 | 0007 | AXX |
 |
|||||
| S9696 | 2024.05.09 | 1 | 1 | S30W10 | 0004 | AXX |
 |
||||
| Total spot count: | 100 | 249 | 122 | ||||||||
| Sunspot number: | 170 | 429 | 262 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 143 | 310 | 183 | (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): | 187 | 236 | 210 | ||||||||
| 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) | 9.5 |
| 2024.05 | 179.1 (1) | 40.1 (2A) / 138.0 (2B) / 191.5 (2C) | (118.3 projected, +1.2) | (11.9) | |
| 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.
