The geomagnetic field was quiet to active on June 4, likely because of effects associated with CH1150. Solar wind speed at SOHO ranged between 340 and 395 km/sec. The high latitude magnetometer at Andenes recorded quiet to unsettled levels.
Solar flux density measured at 20h UT on 2.8 GHz was 168.3 - decreasing 3.6 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 142.36. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 8.9). Three hour interval K indices: 21231242 (planetary), 31232322 (Boulder), 31122132 (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 20 active regions using 2K resolution (SN: 410) and in 15 active regions using 1K resolution (SN: 258) SDO/HMI images.
Region 13319 [S18W82] was mostly quiet and
stable. An M class flare is possible while the region
rotates over the southwest limb.
Region 13320 [N10W08] was quiet and stable.
Region 13321 [S15E02] was quiet and stable.
Region 13323 [S08E22] developed further gaining spots. The region has
polarity intermixing and currently no magnetic deltas. A major flare is
possible. C1 flares: C1.9 @ 06:03 UT
Region 13324 [N16W38] decayed slowly and quietly.
Region 13325 [N10W31] decayed slowly and was mostly quiet. C1 flares:
C1.8 @ 11:22 UT
Region 13326 [N25E51] was quiet and stable.
New region 13327 [S15E69] rotated into view on June 3 and was
numbered by SWPC the next day. The region has a small magnetic delta in a
trailing penumbra and could produce M flares. C1 flares: C1.9 @ 07:43 UT
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S8606 [N10W01] developed slowly and quietly.
S8610 [N30W00] was quiet and stable.
S8613 [S11W12] reemerged with tiny spots.
S8617 [N10E51] was quiet and stable.
S8618 [N19W36] decayed slowly and quietly.
S8621 [S13W79] decayed slowly and quietly.
S8623 [N19E17] was quiet and stable.
S8625 [S28E24] was quiet and stable.
New region S8626 [N17W30] emerged with tiny
spots.
New region S8627 [N08E10] emerged with tiny spots.
New region S8628 [S32W64] emerged with tiny spots.
New region S8629 [N10E83] rotated into view with a tiny spot.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C3.2 | 00:15 | 13319 | GOES16 | simultaneous flares in ARs 13323 and 13327 | |
| C2.8 | 01:18 | 13327 | GOES16 | ||
| C2.3 | 01:30 | 13327 | GOES16 | ||
| C3.0 | 02:01 | 13327 | GOES16 | ||
| C2.4 | 03:05 | 13319 | GOES16 | ||
| C8.8 | 03:49 | 13323 | GOES16 | ||
| C4.0 | 04:23 | 13327 | GOES16 | incorrectly attributed to AR 13323 by SWPC | |
| C2.4 | 07:51 | 13327 | GOES16 | ||
| C3.5 | 08:59 | S10E33 | 13323 | GOES16 | |
| C3.4 | 09:49 | 13327 | GOES16 | ||
| C4.5 | 12:06 | S10E30 | 13323 | GOES16 | |
| C2.4 | 13:32 | 13323 | GOES16 | ||
| C2.8 | 14:19 | 13327 | GOES16 | ||
| C5.8/1N | 14:30 | S17E57 | 13327 | GOES16 | |
| C4.8 | 14:39 | 13327 | GOES16 | ||
| C2.7 | 15:08 | 13319 | GOES16 | ||
| C2.8 | 16:36 | 13323 | GOES16 | ||
| C3.6 | 17:02 | 13323 | GOES16 | ||
| C2.7 | 18:23 | 13327 | GOES16 | simultaneous flare in AR 13323 | |
| C3.4 | 19:22 | 13323 | GOES16 | simultaneous flare in AR 13327 | |
| C3.3 | 20:29 | 13319 | GOES16 | simultaneous flare in AR 13327 | |
| C3.1 | 20:55 | 13327 | GOES16 | ||
| C2.8 | 21:48 | 13327 | GOES16 | ||
| C3.2 | 23:13 | S8606 | GOES16 | simultaneous flare in AR 13327 | |
| C3.2 | 23:37 | 13323 | GOES16 | ||
| C4.9 | 00:17 (flare began at 23:59) | 13327 | GOES16 |
June 2-4: 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 trans equatorial coronal hole (CH1150) rotated across the central meridian on May 31 - June 1. A northern hemisphere coronal hole (CH1152) will likely become Earth facing on June 7.
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 unsettled conditions are likely on June 5-7.
| 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 | ||||||||||
| 13316 | 2023.05.24 2023.05.26 |
N09W87 | |||||||||
| 13319 | 2023.05.27 2023.05.29 |
7 | 11 | 6 | S19W82 | 0220 | EAC | EHO |
 |
 |
area: 0410 location: S18W82 |
| 13320 | 2023.05.28 2023.05.29 |
5 | 6 | 2 | N10W04 | 0030 | CSO | CSO |
 |
 |
area: 0060 location: N10W08 |
| 13321 | 2023.05.29 2023.05.30 |
1 | 28 | 14 | S15E01 | 0170 | HSX | CHO |
 |
 |
area: 0360 location: S15E02 |
| S8606 | 2023.05.29 | 11 | 4 | N10W01 | 0025 | CRO |
 |
 |
|||
| S8608 | 2023.05.29 | S33W55 | |||||||||
| S8609 | 2023.05.30 | N18W23 | |||||||||
| S8610 | 2023.05.30 | 3 | 1 | N30W00 | 0005 | BXO |
 |
 |
|||
| 13324 | 2023.05.30 2023.06.02 |
3 | N11W38 | 0005 | BXO |
 |
 |
||||
| 13323 | 2023.05.30 2023.05.31 |
18 | 75 | 44 | S07E20 | 0320 | EHI | FAC |
 |
 |
beta-gamma area: 0660 location: S08E22 |
| S8613 | 2023.06.01 | S08W09 | |||||||||
| 13325 | 2023.06.01 2023.06.02 |
1 | 5 | 1 | N11W30 | 0020 | HRX | CAO |
 |
 |
location: N10W31 area: 0040 |
| 13326 | 2023.06.02 2023.06.02 |
1 | 1 | 1 | N29E46 | 0070 | HSX | HSX |
 |
 |
location: N25E51 area: 0140 |
| S8617 | 2023.06.02 | 2 | 1 | N10E50 | 0006 | AXX |
 |
 |
|||
| S8618 | 2023.06.03 | 1 | 1 | N19W36 | 0003 | AXX |
 |
 |
|||
| S8621 | 2023.06.03 | 2 | S13W79 | 0002 | BXO |
 |
 |
||||
| 13327 | 2023.06.03 2023.06.04 |
7 | 34 | 21 | S14E67 | 0100 | DAO | EAI |
 |
 |
beta-delta area: 0200 location: S15E69 |
| S8623 | 2023.06.03 | 5 | 2 | N19E17 | 0010 | BXO |
 |
 |
|||
| S8624 | 2023.06.03 | S03W20 |
 |
||||||||
| S8625 | 2023.06.03 | 4 | S28E24 | 0006 | BXO |
 |
 |
||||
| S8626 | 2023.06.04 | 4 | 2 | N17W30 | 0010 | BXO |
 |
||||
| S8627 | 2023.06.04 | 11 | 6 | N08E10 | 0030 | CRO |
 |
||||
| S8628 | 2023.06.04 | 3 | 2 | S32W64 | 0010 | BXO |
 |
||||
| S8629 | 2023.06.04 | 1 | N10E83 | 0002 | AXX |
 |
|||||
| Total spot count: | 40 | 210 | 108 | ||||||||
| Sunspot number: | 110 | 410 | 258 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 78 | 261 | 159 | (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): | 121 | 226 | 206 | ||||||||
| 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 |
| 2021.10 | 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 | 101.0 (+2.3) | 9.33 |
| 2022.12 | 147.9 | 143.4 | 112.8 | (105.8 projected, +4.8) | 10.99 |
| 2023.01 | 182.4 | 176.6 | 143.6 | (112.2 projected, +6.4) | 8.73 |
| 2023.02 | 167.2 | 163.2 | 110.9 | (117.0 projected, +4.8) | 14.48 (current SC25 peak) |
| 2023.03 | 157.2 | 155.6 | 122.6 | (120.1 projected, +3.1) | 14.42 |
| 2023.04 | 145.4 | 146.4 | 96.4 | (125.5 projected, +5.4) | 13.40 |
| 2023.05 | 155.6 | 159.2 | 137.9 | (131.2 projected, +5.7) | 10.9 |
| 2023.06 | 164.8 (1) | 17.1 (2A) / 128.0 (2B) / 160.8 (2C) | (134.3 projected, +3.1) | (6.6) | |
| 2023.07 | (133.8 projected, -0.5) | ||||
| 2023.08 | (134.8 projected, +1.0) | ||||
| 2023.09 | (138.2 projected, +3.4) | ||||
| 2023.10 | (140.1 projected, +1.9) | ||||
| 2023.11 | (142.7 projected max SC25) | ||||
| 2023.12 | (142.6 projected, 0.1) | ||||
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
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.
