The geomagnetic field was very quiet on January 17. Solar wind speed at SOHO ranged between 305 and 377 km/sec. The high latitude magnetometer at Andenes recorded quiet levels. A weak disturbance related to CH1197 appears to have started after 03h on January 18.
Solar flux density measured at 20h UT on 2.8 GHz was 174.1 - decreasing 19.5 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 157.61. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 158.71 on June 27, 2023). The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.5). Three hour interval K indices: 11111111 (planetary), 10112212 (Boulder), 20000112 (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 20 active regions using 2K resolution (SN: 305) and in 19 active regions using 1K resolution (SN: 250) SDO/HMI images.
Region 13540 [S17W80] rotated mostly out of
view and was mostly quiet.
Region 13541 [S23W84] decayed slowly and quietly.
Region 13545 [S06W37] was mostly quiet and stable.
Region 13548 [N12W23] was quiet and stable.
Region 13549 [S21W02] was mostly quiet and stable.
Region 13551 [N26W11] decayed slowly and was mostly quiet. C1 flares:
C1.5 @ 12:59 UT
Region 13553 [N05E17] decayed slowly and was mostly quiet. C1 flares:
C1.7 @ 13:39 UT
Region 13554 [N07E26] was quiet and stable.
Region 13555 [S11E42] gained spots and was mostly quiet.
Region 13556 [N16E52] was quiet and stable.
Region 13557 [S18E61] decayed slowly and quietly.
Region 13558 [S10W80] decayed slowly and was mostly quiet. C1 flares:
C1.9 @ 03:26, C1.6 @ 23:25 UT
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S9329 [S18E37] decayed slowly and quietly.
S9332 [S15E37] decayed slowly and quietly.
S9333 [N11E49] emerged with tiny spots.
New region S9335 [N28E73] rotated into view with mature spots. C1
flares: C1.9 @ 08:00 UT
New region S9336 [S10E78] rotated into view with small spots. C1
flares: C1.5 @ 10:04 UT
New region S9337 [S17E12] was observed with tiny spots in an
old plage area.
New region S9338 [N18E18] was observed with
tiny spots in an old plage area.
New region S9339 [N22E02] was observed with tiny spots in an old
plage area.
New region S9340 [N11E25] emerged with a tiny spot.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C2.2 | 06:48 | S9335 | GOES16 | ||
| C2.6 | 07:24 | GOES16 | |||
| C2.4 | 08:05 | 13541 | GOES16 | ||
| C2.1 | 08:15 | 13549 | GOES16 | ||
| C2.3 | 13:56 | S9335 | GOES16 | ||
| C2.4 | 17:08 | 13540 | GOES16 | ||
| C2.4 | 18:39 | 13540 | GOES16 | ||
| C2.3 | 20:40 | S9335 | GOES16 | ||
| C2.5 | 21:22 | 13558 | GOES16 | ||
| C2.6 | 21:43 | 13541 | GOES16 |
January 15-17: No obviously Earth directed CME 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 (CH1197) rotated across the central meridian on January 13. Another positive polarity northern hemisphere coronal hole (CH1198) will be Earth facing on January 16-18.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle and high latitudes is good. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet to unsettled on January 18 due to weak effects from CH1197. January 19-21 could see quiet to active levels due to effects from CH1198.
| 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 | ||||||||||
| 13541 | 2024.01.04 2024.01.05 |
5 | 2 | S22W90 | 0040 | HRX |
 |
 |
location: S23W84 | ||
| 13540 | 2024.01.04 2024.01.05 |
1 | 1 | S20W95 | 0005 | AXX |
 |
 |
rotated mostly out of view location: S17W80 for last remaining spot |
||
| 13544 | 2024.01.05 2024.01.07 |
N18W80 | |||||||||
| 13558 | 2024.01.06 2024.01.16 |
3 | 4 | 2 | S11W81 | 0050 | CAO | CRO |
 |
 |
location: S10W80 |
| 13545 | 2024.01.08 2024.01.09 |
2 | 8 | 5 | S07W39 | 0120 | CAO | CKO |
 |
 |
area: 0450 location: S06W37 |
| 13546 | 2024.01.08 2024.01.09 |
S24W59 |
 |
location: S23W56 |
|||||||
| S9311 | 2024.01.09 | N19W57 | |||||||||
| 13550 | 2024.01.09 2024.01.12 |
S18W45 |
 |
location: S18W42 | |||||||
| 13552 | 2024.01.09 2024.01.12 |
2 | S24W81 | 0100 | CAO |
location: S22W78 spotless |
|||||
| 13547 | 2024.01.10 2024.01.11 |
N18W65 |
location: N19W57 |
||||||||
| 13551 | 2024.01.10 2024.01.12 |
2 | 9 | 5 | N28W12 | 0030 | HSX | CRI |
 |
 |
location: N26W11 |
| 13548 | 2024.01.10 2024.01.12 |
3 | 3 | N15W24 | 0010 | BXO | BXO |
 |
 |
location: N12W23 area: 0006 |
|
| 13549 | 2024.01.10 2024.01.12 |
5 | 11 | 5 | S22W01 | 0180 | CSO | CKO |
 |
 |
area: 0360 location: S21W02 |
| S9319 | 2024.01.12 | N35W33 | |||||||||
| 13553 | 2024.01.13 2024.01.13 |
35 | 15 | 11 | N09E17 | 0090 | CAO | CAI |
 |
 |
area: 0150 location: N05E17 SWPC count must be a typo |
| S9321 | 2024.01.13 | N11W33 | |||||||||
| 13554 | 2024.01.13 2024.01.15 |
1 | 6 | 5 | N07E24 | 0040 | HSX | CAO |
 |
 |
area: 0060 location: N07E26 |
| S9324 | 2024.01.13 | S19E15 | |||||||||
| 13555 | 2024.01.14 2024.01.15 |
4 | 13 | 9 | S10E45 | 0180 | DSO | ESO |
 |
 |
location: S11E42 |
| S9326 | 2024.01.14 | S10W42 | |||||||||
| S9327 | 2024.01.14 | N12W02 | |||||||||
| S9328 | 2024.01.14 | N21W05 | |||||||||
| S9329 | 2024.01.15 | 2 | 1 | S18E37 | 0008 | AXX |
 |
 |
|||
| 13556 | 2024.01.15 2024.01.16 |
1 | 4 | 3 | N17E52 | 0080 | HSX | HAX |
 |
 |
location: N16E52 area: 0110 |
| 13557 | 2024.01.16 2024.01.16 |
2 | 1 | S13E60 | 0005 | AXX |
 |
 |
was AR S9331 location: S18E61 area: 0030 |
||
| S9332 | 2024.01.16 | 1 | 1 | S15E37 | 0008 | AXX |
 |
 |
|||
| S9333 | 2024.01.16 | N11E36 |
 |
||||||||
| S9334 | 2024.01.16 | N13E04 |
 |
||||||||
| S9335 | 2024.01.17 | 3 | 2 | N28E73 | 0220 | EAO |
 |
||||
| S9336 | 2024.01.17 | 2 | 1 | S10E78 | 0020 | CRO |
 |
||||
| S9337 | 2024.01.17 | 6 | S17E12 | 0012 | BXO |
 |
|||||
| S9338 | 2024.01.17 | 3 | 2 | N18E18 | 0013 | AXX |
 |
||||
| S9339 | 2024.01.17 | 6 | 3 | N22E02 | 0013 | AXX |
 |
||||
| S9340 | 2024.01.17 | 1 | 1 | N11E25 | 0004 | AXX |
 |
||||
| Total spot count: | 58 | 105 | 60 | ||||||||
| Sunspot number: | 158 | 305 | 250 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 103 | 162 | 117 | (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): | 174 | 168 | 200 | ||||||||
| 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 |
| 2022.05 | 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 | 92.6 (+5.9) | 10.92 |
| 2022.09 | 135.1 | 136.5 | 96.0 | 96.5 (+3.9) | 12.18 |
| 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 | 121.0 (+3.2) | 14.42 |
| 2023.04 | 145.4 | 146.4 | 97.6 | 122.7 (+1.7) | 13.40 |
| 2023.05 | 155.6 | 159.2 | 137.4 | 123.9 (+1.2) | 10.67 |
| 2023.06 | 161.7 | 166.8 | 160.5 | 125.0 (+1.1) (SC25 solar max candidate) |
8.95 |
| 2023.07 | 176.4 | 182.2 | 160.0 | (124.6 projected, -0.4) | 8.15 |
| 2023.08 | 153.7 | 157.6 | 114.8 | (124.1 projected, -0.5) | 7.19 |
| 2023.09 | 154.4 | 156.0 | 134.2 | (123.8 projected, -0.3) | 14.26 |
| 2023.10 | 142.8 | 141.9 | 99.4 | (124.6 projected, +0.8) | 8.16 |
| 2023.11 | 153.5 | 150.2 | 105.4 | (124.6 projected, +0.0) | 12.20 |
| 2023.12 | 151.1 | 146.4 | 114.2 | (121.2 projected, -3.4) | 9.60 |
| 2024.01 | 168.8 (1) | 76.1 (2A) / 138.8 (2B) / 154.5 (2C) | (117.9 projected, -3.3) | (5.0) | |
| 2024.02 | (117.1 projected, -0.8) | ||||
| 2024.03 | (116.6 projected, -0.5) | ||||
| 2024.04 | (116.6 projected, +0.0) | ||||
| 2024.05 | (117.0 projected, -0.8) | ||||
| 2024.06 | (114.9 projected, -2.1) | ||||
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
The relatively low solar activity during the last months of 2023 significantly increased the possibility that solar cycle 25 has already peaked. Whether the first peak in June 2023 will be the actual solar max will not be known for some time. Due to the relatively high solar activity early in 2023 it is unlikely there will be another solar max candidate, if at all, until at least May 2024. Both the northern and southern polar fields, as well as the averaged total field, have already reversed polarities.
--------------------------------------------------------------------------------------
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.
