The geomagnetic field was at quiet levels on June 1. The high latitude magnetometer at Andenes recorded quiet to active levels. The above 10 MeV proton flux was at background levels at the end of the day.
Solar flux density measured at 17h UT on 2.8 GHz was 187.9 - increasing 11.0 over the previous solar rotation (the recorded value at 20UT was discarded as it was flare enhanced). (Centered 1 year average SF at 1 AU - 183 days ago: 161.38. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 161.38 on December 2, 2023). The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.0). Three hour interval K indices: 20111110 (planetary), 21122211 (Boulder), 43123300 (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 16 active regions using 2K resolution (SN: 438) and in 15 active regions using 1K resolution (SN: 287) SDO/HMI images.
Region 13690 [N16W45]
was quiet and stable.
Region 13691 [N26W31] decayed further and produced several C flares.
Region 13693 [N06W48] decayed slowly and quietly.
Region 13695 [N27W16] developed as new flux emerged. A small magnetic
delta configuration formed and minor M class flaring is possible.
Region 13696 [N09W11] decayed slowly and quietly.
Region 13697 [S18E22] displayed slight decay in the penumbra
containing the most significant magnetic delta configuration. Both X flares
had their origin in the leading spot section, while the M7 LDE was triggered
by the X1.0 flare and was located in the trailing spot section. Some penumbral
area was gained in the eastern parts of the region. Further major
flares are likely.
Region 13698 [N22E10] expanded longitudinally and lost most of the
polarity intermixing. As a result of this development the region was
significantly less active than during the previous day. developed slowly and
produced several C flares.
Region 13699 [N03W09] matured somewhat and was quiet.
New region 13700 [S04W37] emerged with many spots and could produce
an M class flare.
New region 13701 [S04E31] emerged on May 31 and was numbered the next
day by SWPC as the region developed further.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S9750 [N22W18] was quiet and stable.
S9755 [N21W28] was quiet and stable.
S9758 [S09E48] was quiet and stable.
New region S9760 [N11E51] emerged with a tiny
spot.
New region S9761 [N17E83] rotated into view with a mature spot.
New region S9762 [S14E59] emerged with tiny spots.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C2.1 | 00:20 | 13691 | GOES16 | ||
| C2.9 | 00:58 | 13691 | GOES16 | ||
| C3.1 | 02:29 | 13691 | GOES16 | ||
| C2.9 | 02:39 | 13697 | GOES16 | ||
| C3.4 | 02:58 | 13697 | GOES16 | ||
| C2.6 | 03:15 | 13697 | GOES16 | ||
| C2.4 | 03:30 | 13691 | GOES16 | ||
| C2.1 | 03:38 | 13697 | GOES16 | ||
| C2.1 | 04:23 | 13697 | GOES16 | ||
| C3.8 | 04:57 | 13697 | GOES16 | ||
| C3.2 | 05:11 | 13691 | GOES16 | ||
| C2.4 | 05:24 | 13697 | GOES16 | ||
| C2.3 | 05:33 | 13697 | GOES16 | ||
| C2.2 | 06:01 | 13697 | GOES16 | ||
| C3.4 | 06:27 | 13697 | GOES16 | ||
| C7.5 | 07:01 | 13697 | GOES16 | ||
| C4.0 | 08:12 | 13698 | GOES16 | ||
| X1.4 | 08:48 | 13697 | GOES16 | ||
| C6.3 | 10:28 | 13700 | GOES16 | ||
| C6.8 | 10:55 | 13697 | GOES16 | simultaneous flare near the southwest limb | |
| C4.3 | 12:58 | 13697 | GOES16 | ||
| C3.0 | 13:13 | 13691 | GOES16 | ||
| C2.9 | 13:41 | 13697 | GOES16 | ||
| C3.6 | 13:59 | 13697 | GOES16 | ||
| C4.6 | 14:21 | 13697 | GOES16 | ||
| C4.0 | 15:21 | 13700 | GOES16 | ||
| C2.8 | 15:43 | 13700 | GOES16 | ||
| C2.6 | 16:35 | 13700 | GOES16 | incorrectly attributed to AR 13691 by SWPC | |
| C2.6 | 17:27 | 13691 | GOES16 | incorrectly attributed to AR 13700 by SWPC | |
| X1.0/2B | 18:36 | 13697 | GOES16 | ||
| M7.3 | 19:39 | 13697 | GOES16 | LDE, full halo CME. Moderate type II and weak type IV radio sweeps | |
| C4.7 | 23:53 | 13697 | GOES16 |
May 30-31: No obviously Earth directed CME observed.
June 1: An asymmetrical full halo CME was observed after the M7 long
duration event in AR 13697 peaking at 19:39 UT. The CME could reach Earth
during the first half of June 4.
[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]
No obvious coronal holes are currently in or near Earth facing locations.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle and high latitudes is poor to fair. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be at quiet levels on June 2-3 and early on June 4. The June 1 CME is likely to reach Earth before noon on June 4 and cause unsettled to major, perhaps severe, storm conditions.
| 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 | ||||||||||
| 13690 | 2024.05.23 2024.05.23 |
1 | 2 | 1 | N17W46 | 0010 | AXX | HRX |
 |
 |
location: N16W45 |
| 13691 | 2024.05.24 2024.05.25 |
21 | 45 | 24 | N25W32 | 0220 | DSC | DAI |
 |
 |
location: N26W31 area: 0130 |
| 13692 | 2024.05.24 2024.05.25 |
S08W81 | location: S09W77 | ||||||||
| 13693 | 2024.05.25 2024.05.26 |
2 | 3 | 2 | N04W47 | 0010 | BXO | BXO |
 |
 |
location: N06W48 |
| 13696 | 2024.05.25 2024.05.26 |
3 | 3 | N08W14 | 0015 | AXX |
 |
 |
location: N09W11 |
||
| 13694 | 2024.05.26 | S12W40 | location: S15W30 | ||||||||
| 13695 | 2024.05.26 2024.05.26 |
5 | 25 | 15 | N27W19 | 0010 | BXO | DRI |
 |
 |
beta-gamma-delta location: N27W16 area: 0090 |
| 13697 | 2024.05.27 2024.05.28 |
26 | 105 | 40 | S18E21 | 0380 | EKC | EKC |
 |
 |
beta-gamma-delta location: S18E22 area: 0820 |
| S9748 | 2024.05.27 | S22W30 | |||||||||
| S9750 | 2024.05.28 | 5 | 2 | N22W18 | 0010 | BXO |
 |
 |
|||
| 13698 | 2024.05.28 2024.05.30 |
11 | 29 | 13 | N22E10 | 0160 | DSI | EAI |
 |
 |
beta-gamma area: 0300 |
| S9753 | 2024.05.28 | S30W40 | |||||||||
| S9755 | 2024.05.30 | 1 | 1 | N21W28 | 0007 | HRX |
 |
 |
|||
| 13699 | 2024.05.31 2024.05.31 |
12 | 19 | 12 | N04W21 | 0120 | DAO | DAI |
 |
 |
area: 0260 location: N03W19 |
| 13701 | 2024.05.31 2024.06.01 |
9 | 13 | 8 | S04E30 | 0060 | CAI | DRI |
 |
 |
beta-gamma location: S04E31 |
| S9758 | 2024.05.31 | 1 | S09E48 | 0002 | AXX |
 |
 |
||||
| 13700 | 2024.06.01 2024.06.01 |
17 | 23 | 13 | S04W37 | 0140 | DAI | DAI |
 |
|
was AR S9759 area: 0240 |
| S9760 | 2024.06.01 | 1 | 1 | N11E51 | 0004 | AXX |
 |
||||
| S9761 | 2024.06.01 | 1 | 1 | N17E83 | 0130 | HSX |
 |
||||
| S9762 | 2024.06.01 | 2 | 1 | S14E59 | 0004 | AXX |
 |
||||
| Total spot count: | 104 | 278 | 137 | ||||||||
| Sunspot number: | 194 | 438 | 287 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 144 | 327 | 186 | (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): | 213 | 241 | 230 | ||||||||
| 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 |
| 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) | 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 | 127.8 (+3.0) | 12.20 |
| 2023.12 | 151.1 | 146.4 | 114.2 | (128.7 projected, +0.9) | 9.60 |
| 2024.01 | 164.6 | 159.3 | 123.0 | (127.0 projected, -1.7) | 5.46 |
| 2024.02 | 172.5 | 168.3 | 124.7 | (126.2 projected, -0.8) | 5.31 |
| 2024.03 | 154.4 | 152.9 | 104.9 | (125.6 projected, -0.6) | 11.03 |
| 2024.04 | 161.3 | 162.6 | 136.5 | (125.6 projected, -0.0) | 9.69 |
| 2024.05 | 187.8 | 191.9 | 171.7 (SC25 peak) | (126.7 projected, +1.1) | 23.6 (current SC25 peak) |
| 2024.06 | 187.9 (1) | 6.5 (2A) / 194 (2B) / 180.7 (2C) | (125.9 projected, -0.8) | (4.0) | |
| 2024.07 | (124.2 projected, -1.7) | ||||
| 2024.08 | (122.2 projected, -2.0) | ||||
| 2024.09 | (121.0 projected, -1.2) | ||||
| 2024.10 | (119.6 projected, -1.4) | ||||
| 2024.11 | (114.5 projected, -5.1) | ||||
| 2024.12 | (109.1 projected, -5.4) | ||||
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.
