The geomagnetic field was at quiet to unsettled levels on June 17, weakly under the influence of effects associated with CH1301. Solar wind speed at SOHO ranged between 454 and 586 km/sec, averaging 475 km/sec (+18 km/sec compared to the previous day). The high latitude magnetometer at Andenes recorded quiet to minor storm levels. The above 10 MeV proton flux was at background levels all day.
Solar flux density measured at 20h UT on 2.8 GHz was 139.2 - increasing 19.8 over the previous solar rotation. The 365 day average solar flux at 1 AU was 187.81 (183 days ago). SC25 365d peak: 195.86 on October 13, 2024. The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 7.8). Three hour interval K indices: 12213222 (planetary), 21323324 (Boulder), 23224353 (Andenes).
The background x-ray flux is at the class C2 level (GOES 19).
At the time of counting spots (see image time), spots were observed in 13 active regions using 2K resolution (SN: 284) and in 11 active regions using 1K resolution (SN: 194) SDO/HMI images.
AR 14111 [N15W39] was mostly quiet and stable.
AR 14113 [N10W22] decayed further and was quiet.
AR 14114 [N18W11] lost most magnetic delta configurations with only a
tiny delta remaining in a leading spot section penumbra. There is still
significant polarity intermixing. The X1.2 flare peaking at 21:49 UT
occurred just west of the largest penumbra in an area where positive
polarity spots are squeezed between the large negative trailing penumbra and
another area with smaller negative polarity spots. The region is merging
with the leading spot section of AR 14115. This could cause significant
magnetic shear between the largest spots of both these ARs.
AR 14115 [N20W01] is about to be split with the leader spot merging
with AR 14114. The trailing spot section is developing into an AR of its own
with new positive polarity spots emerging. An M2.2 flare was observed at
22:05 UT in trailing spot section.
AR 14116 [S11W16] was quiet and stable.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S11159 [S03W05] was quiet and stable.
S11163 [N23W04] developed slowly and quietly. A C9.4 flare was
recorded at 03:13 UT on June 18. This AR could be merging with AR 14114 as
well.
S11165 [N12E18] was quiet and stable.
New AR S11166 [S12E30] emerged before noon with a few spots, then
decayed slowly.
New AR S11167 [S13E78] rotated into view with several spots and could
have major flare potential. The region was unstable and the most active
flare source on the visible disk. In addition to the M1 flare at midnight, a C5.9
flare was recorded at 03:37 UT on June 18. C1 flares: C1.8 @ 19:40 UT
New AR S11168 [S02W47] emerged with tiny spots.
New AR S11169 [S09E35] emerged with tiny spots.
New AR S11170 [S10E82] rotated into view with small spots.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C4.1 | 00:53 | behind SW limb | 14110 | GOES18 | |
| C6.8 | 01:26 | N18E01 | 14114 | GOES18 | |
| C3.2 | 03:50 | 14110 | GOES18 | ||
| C4.1 | 04:27 | S11167 | GOES18 | ||
| C2.8 | 05:49 | S11167 | GOES18 | ||
| C9.9 | 06:21 | S11167 | GOES18 | ||
| C5.1 | 06:43 | S11163 | GOES18 | simultaneous flare in AR S11167 | |
| C4.0 | 06:53 | 14115 | GOES18 | ||
| C3.8 | 06:58 | S11163 | GOES18 | ||
| C4.0 | 08:03 | behind NW limb | GOES18 | ||
| C5.5 | 08:13 | S11167 | GOES18 | ||
| C4.7 | 08:53 | S11167 | GOES18 | ||
| C4.4 | 09:52 | S11167 | GOES18 | ||
| C3.2 | 10:19 | S11170 | GOES18 | ||
| C3.5 | 11:07 | 14114 | GOES18 | ||
| C2.2 | 11:53 | 14114 | GOES18 | ||
| C2.2 | 12:43 | 14114 | GOES18 | ||
| C2.3 | 12:50 | 14114 | GOES18 | ||
| C2.9 | 13:36 | 14110 | GOES18 | ||
| C3.1 | 14:03 | S11167 | GOES18 | ||
| C3.4 | 14:14 | S11163 | GOES18 | ||
| C3.1 | 14:40 | S11167 | GOES18 | ||
| C2.5 | 14:51 | S11167 | GOES18 | ||
| C2.1 | 15:42 | 14114 | GOES18 | ||
| C2.3 | 20:38 | S11163 | GOES18 | ||
| C3.4 | 20:59 | S11167 | GOES18 | ||
| X1.2/2B | 21:49 | N19W10 (SDO/AIA) | 14114 | GOES18 | |
| M2.2 | 22:05 | N21E05 | 14115 | GOES18 | |
| C2.8 | 23:28 | S11167 | GOES18 | ||
| M1.5 | 00:00 | S11167 | GOES18 |
June 16-17: No obviously Earth directed CMEs.
June 15: AR 14114 produced 2 CMEs that may have had Earth directed
components. The first one was associated with a C7.5 flare peaking at 03:29 and the
last one was observed after the major M8 flare at 18:06 UT. Both CMEs were
brightest off the north pole. The latter one was at least a partial halo CME
with faint extensions off east and west limbs. Components from this CME
could reach Earth sometime between late on June 17 and noon on June 18.
[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 large recurrent polar connected positive polarity southern hemisphere coronal hole (CH1301) will be Earth facing on June 11-19.
The geomagnetic field is expected to be at quiet to active levels on June 18-21 due to effects associated with CH1301. If the last of the 2 June 15 CMEs reaches Earth, unsettled to major storm levels will be possible on June 17-18.
| 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 |
STAR | SWPC | STAR | Current | Previous | ||||||
| 2K | 1K | ||||||||||
| 14111 | 2025.06.08 2025.06.09 |
5 | 15 | 8 | N15W37 | 0070 | CSO | CAI |
 |
 |
beta-gamma was AR S11139 area: 0150 location: N15W39 |
| 14112 | 2025.06.08 | S09W61 |
 |
was AR S11141 | |||||||
| 14113 | 2025.06.10 2025.06.11 |
1 | 5 | 3 | N10W22 | 0010 | AXX | HRX |
 |
 |
was AR S11149 |
| 14114 | 2025.06.10 2025.06.11 |
32 | 64 | 39 | N18W12 | 0330 | EKC | EKC |
 |
 |
beta-gamma-delta was AR S11150 area: 0600 location: N18W11 |
| 14115 | 2025.06.11 2025.06.12 |
5 | 14 | 8 | N20W01 | 0120 | CSO | ESO |
 |
 |
was AR S11151 area: 0230 AR will likely be split with the leader spot merging with AR 14114 and the trailing spots still AR 14115 |
| 14116 | 2025.06.12 2025.06.14 |
4 | 12 | 8 | S12W16 | 0070 | DSO | DSO |
 |
 |
was AR S11157 location: S11W16 area: 0130 |
| S11158 | 2025.06.12 | S07W35 | |||||||||
| S11159 | 2025.06.13 | 5 | 2 | S03W05 | 0010 | BXO |
 |
 |
|||
| S11160 | 2025.06.14 | S15W27 |
 |
||||||||
| S11162 | 2025.06.14 | N21E10 | |||||||||
| S11163 | 2025.06.15 | 16 | 7 | N23W04 | 0060 | DRI |
 |
 |
beta-gamma | ||
| S11164 | 2025.06.16 | N22W29 |
 |
||||||||
| S11165 | 2025.06.16 | 3 | N12E18 | 0005 | BXO |
 |
 |
||||
| S11166 | 2025.06.17 | 1 | 1 | S09E35 | 0003 | AXX |
 |
||||
| S11167 | 2025.06.17 | 11 | 6 | S14E78 | 0160 | DAI |
 |
beta-gamma | |||
| S11168 | 2025.06.17 | 2 | S02W47 | 0003 | AXX |
 |
|||||
| S11169 | 2025.06.17 | 3 | 1 | S09E35 | 0006 | BXO |
 |
||||
| S11170 | 2025.06.17 | 3 | 1 | S10E82 | 0040 | CAO |
 |
||||
| Total spot count: | 47 | 154 | 84 | ||||||||
| Sunspot number: | 97 | 284 | 194 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 72 | 195 | 125 | (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): | 105 | 156 | 155 | ||||||||
| Month | Average solar flux | International sunspot number (WDC-SILSO) |
Smoothed sunspot number (4) | Average
ap (3) |
|
|---|---|---|---|---|---|
| Measured | 1 AU | ||||
| 2024.01 | 164.6 | 159.3 | 126.0 | 131.2 (+1.7) | 5.46 |
| 2024.02 | 172.5 | 168.3 | 123.0 | 136.9 (+5.7) | 5.31 |
| 2024.03 | 154.4 | 152.9 | 103.7 | 141.4 (+4.5) | 11.03 |
| 2024.04 | 161.3 | 162.6 | 137.0 | 144.5 (+3.1) | 9.69 |
| 2024.05 | 187.7 | 191.9 | 172.1 | 149.1 (+4.6) | 23.56 (SC25 peak) |
| 2024.06 | 184.3 | 190.2 | 164.1 | 152.8 (+3.7) | 10.24 |
| 2024.07 | 196.6 | 203.0 | 196.8 | 155.0 (+2.3) | 7.13 |
| 2024.08 | 246.1 (cycle peak) |
252.2 | 216.0 (SC25 peak) | 156.8 (+1.8) | 15.96 |
| 2024.09 | 195.7 | 197.8 | 141.1 | 159.4 (+1.6) | 15.36 |
| 2024.10 | 221.0 | 219.6 | 165.8 | 160.8 (+1.4) (SC25 solar max) | 18.99 |
| 2024.11 | 199.6 | 195.3 | 154.1 | 157.0 (-3.8) | 9.33 |
| 2024.12 | 197.3 | 191.2 | 154.6 | (150.7 projected, -6.3) | 8.42 |
| 2025.01 | 190.3 | 184.2 | 137.0 | (144.2 projected, -6.5) | 13.17 |
| 2025.02 | 184.2 | 179.7 | 154.6 | (135.6 projected, -8.6) | 14.42 |
| 2025.03 | 163.7 | 162.1 | 134.2 | (129.2 projected, -6.4) | 15.96 |
| 2025.04 | 162.5 | 163.6 | 140.6 | (124.6 projected, -4.6) | 17.62 |
| 2025.05 | 135.3 | 138.3 | 79.2 | (119.3 projected, -5.3) | 17.26 |
| 2025.06 | 136.4 (1) | 60.5 (2A) / 106.8 (2B) / 127.1 (2C) | (114.4 projected, -4.9) | (28.4) | |
| 2025.07 | (110.2 projected, -4.2) | ||||
| 2025.08 | (105.5 projected, -4.7) | ||||
| 2025.09 | (101.2 projected, -4.3) | ||||
| 2025.10 | (97.3 projected, -3.9) | ||||
| 2025.11 | (95.0 projected, -2.3) | ||||
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 27 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
Sunspot activity has been on a slowly decreasing trend since September
2024 (using the average solar flux over 3 solar rotations as a proxy). The
decline has become more obvious during the first half of May 2025 with solar
flux on May 12 at its lowest level since April 4, 2024. The solar max phase
of solar cycle 25 was considerably shorter than that of the most recent
solar cycles.
All 365 days smoothed sunspot numbers peaked on October 11-12, 2024,
very likely making this the peak of SC25 (STAR 1K 365d peak: 236.1, STAR 2K
365d peak: 364.3, NOAA SN 365d peak: 156.0, ISN 365d peak: 163.6). The 365d
smoothed solar flux peaked on October 13, 2024, just 1.7% below the SC23
peak, and 62.6% above the SC24 peak.
--------------------------------------------------------------------------------------
This report has been prepared by Jan Alvestad. It is based on the analysis of data from whichever 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.
