The geomagnetic field was at quiet to minor levels on May 6 under the influence of a coronal hole high speed stream. The high latitude magnetometer at Andenes recorded quiet to minor storm levels. The above 10 MeV proton flux was at background levels at the end of the day.
Solar flux density measured at 20h UT on 2.8 GHz was 171.2 - increasing 46.8 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 158.58. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 158.71 on October 28, 2023). 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: 52234222 (planetary), 53223321 (Boulder), 52334342 (Andenes).
The background x-ray flux is at the class C2 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 15 active regions using 2K resolution (SN: 346) and in 12 active regions using 1K resolution (SN: 223) SDO/HMI images.
Region 13661 [N23W27] decayed slowly and
quietly.
Region 13662 [N29W71] decayed slowly and quietly.
Region 13663 [N25W43] decayed fairly quickly losing most of the spots
in the northeast and most of the magnetic delta configuration in the central
section of the spot group. Further major flares are possible until the
region rotates off the visible disk.
Region 13664 [S20E02] displayed no major changes and produced only a
few C flares despite the presence of a magnetic delta in the central southern spot
section. The very quick development of AR S9676 just east of AR 13664
created another magnetic delta structure where the easternmost spots nearly
merged with leader spots of AR S9676. The super group consisting of AR
13664, AR S9676 and AR 13668 could produce major flares.
Region 13665 [S05E22] decayed slowly and quietly.
Region 13666 [N07W25] was quiet and stable.
Region 13667 [N26E47] was quiet and stable.
Region 13668 [S17E15] developed slowly and began to interact with
rapidly emerging AR S9676.
Region 13669 [S09E29] was quiet and stable.
New region 13670 [N16E69] rotated into view on May 5 and was numbered
the next day by SWPC.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S9660 [N11W10] was quiet and stable.
S9676 [S19E07] developed very quickly and began interacting with both
ARs 13668 and 13664. Major flaring is possible as a significant magnetic
delta formed in the southernmost spot section as well as with the trailing
spots of AR 13664.
New region S9679 [N09E28] was observed with tiny spots in an old
plage area.
New region S9680 [N20E72] emerged with tiny spots near the
northeast limb.
New region S9681 [S31W18] was observed with tiny spots in an old
plage area.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C2.2 | 00:12 | 13663 | GOES16 | ||
| C3.9 | 00:37 | N26W24 | 13663 | GOES16 | simultaneous flare in AR 13664 |
| C8.5 | 00:57 | 13664 | GOES16 | ||
| M1.6/2F | 01:06 | N24W32 | 13663 | GOES16 | |
| C4.3 | 02:16 | 13664 | GOES16 | ||
| C3.0 | 02:51 | 13663 | GOES16 | ||
| C3.7 | 03:17 | 13663 | GOES16 | ||
| C5.8 | 03:51 | 13663 | GOES16 | ||
| C6.7 | 04:17 | 13663 | GOES16 | ||
| C8.8 | 04:22 | S18E13 | 13664 | GOES16 | simultaneous flare in AR S9676 |
| C5.4 | 04:44 | 13663 | GOES16 | ||
| C5.5 | 04:48 | 13664 | GOES16 | ||
| M1.3 | 05:28 | 13663 | GOES16 | ||
| M6.5 | 06:13 | 13663 | GOES16 | ||
| X4.5/3B | 06:35 | N26W35 | 13663 | GOES16 | |
| M4.6 | 07:22 | S9676 | GOES16 | ||
| C9.0 | 09:02 | S9676 | GOES16 | ||
| C8.6 | 09:08 | 13663 | GOES16 | ||
| M1.5 | 09:59 | 13663 | GOES16 | ||
| C7.4 | 10:13 | 13663 | GOES16 | simultaneous flare in AR 13664 | |
| C6.3 | 10:24 | 13663 | GOES16 | ||
| C6.5 | 11:00 | 13663 | GOES16 | simultaneous flare in AR S9676 | |
| C4.9 | 11:27 | 13663 | GOES16 | ||
| C5.1 | 11:56 | S9676 | GOES16 | ||
| C5.5 | 12:25 | 13663 | GOES16 | ||
| C6.7 | 12:36 | 13663 | GOES16 | ||
| C6.7 | 12:48 | 13663 | GOES16 | ||
| C9.3 | 12:56 | 13663 | GOES16 | ||
| C4.3 | 13:42 | 13663 | GOES16 | ||
| C3.2 | 14:12 | 13663 | GOES16 | ||
| C4.4/1F | 14:30 | N24W37 | 13663 | GOES16 | |
| C2.0 | 15:18 | 13663 | GOES16 | ||
| C6.2/1N | 15:34 | N26W35 | 13663 | GOES16 | |
| C4.3 | 17:09 | N25W44 | 13663 | GOES16 | |
| C2.7 | 17:39 | 13663 | GOES16 | ||
| C3.7 | 18:22 | 13663 | GOES16 | ||
| C3.0 | 18:42 | 13663 | GOES16 | ||
| C2.1 | 18:56 | 13663 | GOES16 | ||
| C9.4/1F | 19:18 | 13663 | GOES16 | ||
| C8.9 | 19:25 | 13663 | GOES16 | ||
| C3.0 | 20:08 | 13663 | GOES16 | ||
| C2.6 | 20:22 | 13663 | GOES16 | ||
| C3.4 | 20:31 | S9676 | GOES16 | ||
| C3.3 | 20:47 | 13663 | GOES16 | ||
| C2.9 | 20:47 | 13663 | GOES16 | ||
| C2.4 | 21:05 | 13668 | GOES16 | ||
| C3.3 | 21:20 | 13663 | GOES16 | ||
| C2.9 | 21:33 | 13663 | GOES16 | ||
| M1.2/2N | 21:48 | 13663 | GOES16 | ||
| M4.3 | 22:27 | 13663 | GOES16 | ||
| M1.1 | 23:57 | 13663 | GOES16 |
May 4-5: LASCO imagery was unavailable. Due to the large amount of M
and X
flares from spot groups not too far from the central meridian, it is likely
there were some CMEs with Earth directed components.
May 6: 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 (CH1219) was Earth facing on May 1-2. A positive polarity trans equatorial coronal hole (CH1220) rotated across the central meridian on May 3. A positive polarity northern hemisphere coronal hole (CH1221) will likely become Earth facing on May 9-10.
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 minor storm on May 7-9 due to possible CME effects and effects related to CH1219 and CH1220.
| 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 | ||||||||||
| 13660 | 2024.04.26 2024.04.27 |
N11W61 | location: N10W56 | ||||||||
| 13662 | 2024.04.27 2024.04.29 |
1 | 2 | 1 | N27W71 | 0020 | AXX | HRX |
 |
 |
location: N29W71 |
| 13661 | 2024.04.28 2024.04.29 |
1 | 5 | 2 | N23W28 | 0020 | HSX | CRO |
 |
 |
|
| 13663 | 2024.04.29 2024.04.30 |
18 | 47 | 31 | N25W45 | 0600 | FKC | FKC |
 |
 |
beta-gamma-delta area: 0860 location N25W43 |
| 13664 | 2024.04.30 2024.05.01 |
22 | 47 | 29 | S19E02 | 0560 | EKC | EKC |
 |
 |
beta-gamma-delta area: 0690 location: S20E02 |
| S9660 | 2024.04.30 | 7 | 3 | N11W10 | 0013 | BXO |
 |
 |
|||
| S9661 | 2024.04.30 | S22W41 |
 |
||||||||
| S9662 | 2024.05.01 | N20W46 | |||||||||
| 13665 | 2024.05.01 2024.05.02 |
4 | S05E15 | 0010 | BXO |
 |
 |
location: S05E22 |
|||
| 13666 | 2024.05.02 2024.05.03 |
2 | 10 | 4 | N07W27 | 0070 | CSO | CAO |
 |
 |
area: 0160 location: N07W25 |
| 13669 | 2024.05.02 2024.05.05 |
1 | 3 | 2 | S08E29 | 0010 | AXX | HRX |
 |
 |
area: 0020 |
| S9668 | 2024.05.02 | N12W37 | |||||||||
| 13668 | 2024.05.03 2024.05.05 |
11 | 20 | 13 | S17E13 | 0050 | DAO | DRI | see AR 13664 |
 |
beta-gamma area: 0100 location: S17E15 |
| S9670 | 2024.05.03 | N04E15 | |||||||||
| 13667 | 2024.05.03 2024.05.04 |
1 | 2 | 1 | N27E44 | 0130 | HSX | HKX |
 |
 |
area: 0270 location: N26E47 |
| S9672 | 2024.05.03 | S33E18 | |||||||||
| S9673 | 2024.05.04 | S11W22 |
 |
||||||||
| S9674 | 2024.05.04 | N01W25 | |||||||||
| S9675 | 2024.05.05 | S10W17 |
 |
||||||||
| S9676 | 2024.05.05 | 40 | 15 | S19E07 | 0300 | DAC | see AR 13664 |
 |
beta-gamma-delta | ||
| 13670 | 2024.05.05 2024.05.06 |
1 | 1 | 1 | N17E66 | 0020 | HAX | HSX |
 |
 |
area: 0050 location: N16E69 |
| S9679 | 2024.05.06 | 3 | 1 | N09E28 | 0005 | BXO |
 |
||||
| S9680 | 2024.05.06 | 2 | N20E72 | 0003 | BXO |
 |
|||||
| S9681 | 2024.05.06 | 3 | S31W18 | 0004 | AXX |
 |
|||||
| Total spot count: | 58 | 196 | 103 | ||||||||
| Sunspot number: | 148 | 346 | 223 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 103 | 253 | 160 | (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): | 163 | 190 | 178 | ||||||||
| 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 | 158.1 (1) | 25.4 (2A) / 131.0 (2B) / 181.8 (2C) | (118.3 projected, +1.2) | (15.1) | |
| 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.
