The geomagnetic field was at quiet to unsettled levels on June 17 under the influence of weak effects from CH1226. 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 179.9 - decreasing 10.9 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 162.25. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 162.25 on December 18, 2023). The Potsdam WDC planetary A index was 11.0 (STAR Ap - based on the mean of three hour interval ap indices: 11.0). Three hour interval K indices: 23222333 (planetary), 23223333 (Boulder), 23223355 (Andenes).
The background x-ray flux is at the class C1 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 10 active regions using 2K resolution (SN: 292) and in 8 active regions using 1K resolution (SN: 180) SDO/HMI images.
Region 13708 [S20W70] decayed slowly and
quietly.
Region 13709 [S08W67] decayed slowly and was mostly quiet. C1 flares:
C1.8 @ 03:08 UT
Region 13711 [S12W58] decayed slowly. C1 flares: C1.8 @ 03:07, C1.8 @
16:51 UT
Region 13712 [S26W11] became more complex again as a new magnetic
delta configuration formed in the central spot section. The trailing and
central spot sections merged forming an 11 degrees (longitude) wide
elongated penumbra. Major flaring is possible. C1 flares: C1.3 @ 00:06, C1.6
@ 00:15, C1.9 @ 02:06, C1.6 @ 02:29, C1.6 @ 02:39, C1.6 @ 05:56, C1.5 @
12:01, C1.8 @ 14:45, C1.8 @ 16:38, C1.8 @ 18:07, C1.8 @ 19:46, C1.9 @ 23:54
UT
Region 13713 [S13E04] developed as new spots formed. M class flares
are possible.
Region 13714 [N14W42] was quiet and stable.
Region 13716 [N09W05] decayed in the trailing spot section and lost
area. M class flares are possible.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S9803 [S09W36] was quiet and stable.
New region S9806 [S08E21] emerged with tiny spots.
New region S9807 [S12W16] emerged with a tiny spot.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C2.2 | 00:27 | 13712 | GOES16 | ||
| C6.2 | 00:49 | 13712 | GOES16 | ||
| C5.8 | 01:06 | 13712 | GOES16 | ||
| C4.2 | 03:37 | 13712 | GOES16 | ||
| C2.6 | 04:02 | 13712 | GOES16 | ||
| C2.3 | 04:52 | 13712 | GOES16 | ||
| C2.6 | 07:27 | 13712 | GOES16 | ||
| M1.5 | 08:04 | S26W13 | 13712 | GOES16 | |
| C3.1 | 09:37 | S14E13 | 13713 | GOES16 | |
| M1.5/1B | 10:46 | S26W13 | 13712 | GOES16 | moderate type II radio sweep |
| C2.0 | 15:04 | 13713 | GOES16 | ||
| C2.0 | 15:26 | 13712 | GOES16 | ||
| C2.0 | 15:53 | 13712 | GOES16 | ||
| M1.3 | 20:35 | S10W52 | 13711 | GOES16 | |
| C2.6 | 22:19 | 13713 | GOES16 | ||
| C2.8 | 22:39 | 13712 | GOES16 | ||
| C6.0 | 22:57 | 13711 | GOES16 | ||
| C2.5 | 23:24 | 13711 | GOES16 | ||
| C2.1 | 23:42 | 13716 | GOES16 | simultaneous flare in AR 13712 |
June 15-17: No obviously Earth directed CME observed. The M1.5 flare in AR 13712 on June 17 at 10:46 UT may be associated with a slow moving CME, however, it is difficult to distinguish this CME from a backsided CME that occurred near the same time.
[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 trans equatorial coronal hole (CH1226) was Earth facing on June 13-14. A negative polarity northern hemisphere coronal hole (CH1228) will be Earth facing on June 18.
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 unsettled on June 18 due to effects from CH1226. Quiet conditions are likely on June 19-20. June 21-22 could see weak effects from CH1228.
| 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 | ||||||||||
| 13707 | 2024.06.05 2024.06.06 |
S14W89 | |||||||||
| 13708 | 2024.06.05 2024.06.06 |
1 | 1 | 1 | S21W71 | 0040 | HAX | HAX |
 |
 |
location: S20W70 |
| 13709 | 2024.06.06 2024.06.07 |
3 | 5 | 2 | S08W66 | 0030 | CAO | HRX |
 |
 |
area: 0020 location: S08W67 |
| 13711 | 2024.06.07 2024.06.09 |
4 | 5 | 2 | S11W53 | 0010 | BXO | CRO |
 |
 |
area: 0020 location: S12W58 |
| 13714 | 2024.06.08 2024.06.12 |
7 | 3 | N14W46 | 0015 | AXX |
 |
 |
location: N14W42 | ||
| S9791 | 2024.06.10 | S24W58 | |||||||||
| 13715 | 2024.06.11 2024.06.12 |
N17W20 |
 |
location: N18W14 | |||||||
| 13712 | 2024.06.11 2024.06.12 |
40 | 60 | 33 | S26W12 | 1100 | EKC | FKC |
 |
 |
beta-gamma-delta area: 1480 |
| 13713 | 2024.06.11 2024.06.12 |
15 | 54 | 29 | S16E01 | 0150 | ESO | ESI |
 |
 |
beta-gamma location: S13E04 area: 0320 |
| S9796 | 2024.06.11 | N27W30 | |||||||||
| S9798 | 2024.06.11 | S20W45 | |||||||||
| 13716 | 2024.06.12 | 35 | 50 | 28 | N10W05 | 0480 | DKC | DAC |
 |
 |
beta-gamma area: 0500 location: N10E09 |
| S9800 | 2024.06.13 | N29W25 | |||||||||
| 13717 | 2024.06.14 2024.06.15 |
3 | N07W63 | 0010 | BXO |
 |
spotless location: N08W58 |
||||
| S9802 | 2024.06.15 | S32E26 | |||||||||
| S9803 | 2024.06.16 | 3 | S09W36 | 0005 | BXO |
 |
 |
||||
| S9804 | 2024.06.16 | N17E09 |
 |
||||||||
| S9805 | 2024.06.16 | S11E54 |
 |
||||||||
| S9806 | 2024.06.17 | 6 | 2 | S08E21 | 0010 | BXO |
 |
||||
| S9807 | 2024.06.17 | 1 | S12W16 | 0002 | AXX |
 |
|||||
| Total spot count: | 101 | 192 | 100 | ||||||||
| Sunspot number: | 171 | 292 | 180 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 136 | 222 | 130 | (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): | 188 | 161 | 144 | ||||||||
| 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 | 187.7 (cycle peak) |
191.9 | 171.7 (SC25 peak) | (126.7 projected, +1.1) | 23.56 (current SC25 peak) |
| 2024.06 | 179.6 (1) | 88.8 (2A) / 156.8 (2B) / 158.7 (2C) | (125.9 projected, -0.8) | (9.0) | |
| 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
May 2024 easily became the month with the highest sunspot counts during solar cycle 25, and early June has seen no change in that pattern of many spot groups, some of which are large and complex. The next candidate for solar max is still uncertain, however, May 20-21, 2024 has all of the smoothed 365d sunspot numbers as well as the 365d smoothed solar flux signalling a peak on those days.
--------------------------------------------------------------------------------------
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.
