The geomagnetic field was quiet to active on February 11 due to CME effects. Solar wind speed at SOHO ranged between 350 and 851 km/sec. The high latitude magnetometer at Andenes recorded quiet to active levels. The above 10 MeV proton flux was at 8 pfu at the end of the day. A solar wind shock was recorded at 01:14 UT at SOHO with solar wind speed abruptly increasing from 353 to 423 km/sec, the arrival of the February 9 CME (transit time: 36 hours). A secondary sudden increase in solar wind speed from 466 to 592 km/sec was observed at 03:12 UT. Proton flux levels dropped significantly after 04h UT.
Solar flux density measured at 20h UT on 2.8 GHz was 180.4 - decreasing 2.1 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 157.11. 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 14 (STAR Ap - based on the mean of three hour interval ap indices: 13.8). Three hour interval K indices: 43332212 (planetary), 43332322 (Boulder), 24331323 (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 12 active regions using 2K resolution (SN: 305) and in 9 active regions using 1K resolution (SN: 187) SDO/HMI images.
Region 13571 [S18W68] developed as new flux
emerged in the trailing spot section.
Region 13576 [S16W24] decayed losing area and spots. A new magnetic
delta structure formed in the northern part of the largest penumbra. A major
M6.5 flare was recorded at 03:48 UT on February 12.
Region 13577 [N23W57] was quiet and stable.
Region 13579 [S11W05] was quiet and stable.
Region 13581 [S21E32] was quiet and stable.
Region 13582 [N05E01] developed early in the day, then decayed
slowly.
Region 13583 [N09E29] developed further and may be capable of
producing a minor M class flare.
Region 13584 [S14E58] was quiet and stable.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S9406 [N15E11] was quiet and stable.
S9416 [S07E03] decayed slowly and quietly.
New region S9418 [N09E02] emerged north of AR
13582 with several spots.
New region S9419 [N27W58] emerged with tiny spots.
A C1.8 flare at 21:02 and a C1.7 flare at 21:52 UT had their origin behind the northeast limb.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C6.3 | 00:17 | 13576 | GOES16 | ||
| C6.2 | 00:28 | 13576 | GOES16 | ||
| C7.3 | 00:38 | S14W05 | 13576 | GOES16 | |
| C2.9 | 01:31 | 13576 | GOES16 | ||
| C3.3 | 01:54 | 13582 | GOES16 | ||
| C2.8 | 02:48 | 13576 | GOES16 | ||
| C3.8 | 03:25 | behind northeast limb | GOES16 | ||
| C4.1 | 03:28 | 13576 | GOES16 | ||
| C4.7 | 08:46 | 13583 | GOES16 | ||
| C3.4 | 09:06 | 13576 | GOES16 | ||
| C2.8 | 09:54 | 13576 | GOES16 | ||
| C2.9 | 11:19 | 13583 | GOES16 | ||
| C2.4 | 12:33 | 13583 | GOES16 | ||
| C2.9 | 14:05 | 13583 | GOES16 | ||
| C2.4 | 15:21 | 13583 | GOES16 | simultaneous flare behind southeast limb | |
| C3.9 | 16:08 | behind southeast limb | GOES16 | ||
| C2.2 | 16:37 | behind northeast limb | GOES16 | ||
| C3.5 | 17:25 | 13583 | GOES16 | ||
| C2.6 | 18:12 | 13576 | GOES16 | ||
| C3.1 | 20:03 | 13576 | GOES16 | ||
| C2.0 | 20:22 | 13576 | GOES16 | ||
| M1.0 | 22:44 | behind northeast limb | GOES16 | ||
| C2.3 | 23:58 | behind northeast limb | GOES16 |
February 9: An impressive asymmetrical full halo CME was observed after the X3.3
proton flare in AR 13575 peaking at 13:14 UT. While the source of this event
was behind the southwest limb, a strong coronal wave was observed over large
parts of the western frontsided hemisphere. The associated CME was very wide and very
fast. This CME reached Earth before 02h UT on February 11.
February 10: A full halo CME was observed after the M3.4 flare peaking at
03:54 UT. As this was a limb event, chances are slim that the CME will reach
Earth on February
12/13. A filament eruption beginning near 06 UT to the south of AR 13576
caused a CME that was observed off the south pole and the southern limbs.
The major M9 flare in AR 13576 at 22:59 UT triggered a large filament
eruption to the north of the spot group. A faint full halo CME was observed
after the flare while a denser CME was observed over the north pole due to
the filament eruption. The halo CME could
impact Earth on February 12/13.
February 11: 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]
No obvious coronal holes are currently in or near Earth facing positions.
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 initially quiet to unsettled on February 12. Late in the day or on February 13 the February 10 CME will likely arrive and cause unsettled to major storm conditions until February 14.
| 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 | ||||||||||
| 13571 | 2024.01.31 2024.02.01 |
3 | 8 | 3 | S17W68 | 0060 | HSX | CSO |
 |
 |
area: 0100 location: S18W68 |
| 13574 | 2024.02.01 2024.02.01 |
N16W60 |
 |
location: N16W58 |
|||||||
| 13577 | 2024.02.02 2024.02.05 |
1 | N22W57 | 0001 | AXX |
 |
 |
location: N23W57 |
|||
| 13576 | 2024.02.03 2024.02.03 |
44 | 81 | 39 | S16W23 | 0740 | FKC | EKC |
 |
 |
beta-gamma-delta area: 0660 location: S16W24 |
| S9401 | 2024.02.04 | S23W57 | |||||||||
| 13578 | 2024.02.04 2024.02.05 |
S04W19 |
 |
location: S04W10 |
|||||||
| S9405 | 2024.02.05 | N39W19 | |||||||||
| S9406 | 2024.02.06 | 5 | N15E11 | 0008 | BXO |
 |
 |
||||
| 13579 | 2024.02.06 2024.02.07 |
1 | 8 | 6 | S09W10 | 0020 | HSX | BXO |
 |
 |
location: S11W05 |
| 13581 | 2024.02.07 2024.02.08 |
2 | 5 | 2 | S21E31 | 0080 | HSX | HSX |
 |
 |
location: S21E32 area: 0160 |
| S9411 | 2024.02.08 | S16W42 |
 |
||||||||
| 13582 | 2024.02.08 2024.02.10 |
9 | 20 | 14 | N06E01 | 0060 | CAO | DSO |
 |
 |
area: 0160 location: N05E01 |
| 13583 | 2024.02.08 2024.02.10 |
14 | 37 | 22 | N09E29 | 0110 | DSO | DAI |
 |
 |
beta-gamma area: 0440 |
| 13584 | 2024.02.09 2024.02.10 |
1 | 4 | 1 | S15E57 | 0020 | HSX | CSO |
 |
 |
area: 0070 |
| S9415 | 2024.02.10 | N14E25 |
 |
||||||||
| S9416 | 2024.02.10 | 1 | S07E03 | 0003 | AXX |
 |
 |
||||
| S9417 | 2024.02.10 | N25E36 |
 |
||||||||
| S9418 | 2024.02.11 | 11 | 7 | N09E02 | 0060 | DRI |
 |
||||
| S9419 | 2024.02.11 | 4 | 3 | N27W58 | 0010 | BXO |
 |
||||
| Total spot count: | 74 | 185 | 97 | ||||||||
| Sunspot number: | 144 | 305 | 187 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 114 | 223 | 135 | (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): | 158 | 168 | 150 | ||||||||
| 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 |
| 2022.06 | 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 | 121.1 (+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 | 124.1 (+1.2) | 10.67 |
| 2023.06 | 161.7 | 166.8 | 160.5 | 125.2 (+1.1) (SC25 solar max candidate) |
8.95 |
| 2023.07 | 176.4 | 182.2 | 160.0 | 124.3 (-0.9) | 8.15 |
| 2023.08 | 153.7 | 157.6 | 114.8 | (123.4 projected, -0.9) | 7.19 |
| 2023.09 | 154.4 | 156.0 | 134.2 | (123.1 projected, -0.3) | 14.26 |
| 2023.10 | 142.8 | 141.9 | 99.4 | (123.9 projected, +0.8) | 8.16 |
| 2023.11 | 153.5 | 150.2 | 105.4 | (123.9 projected, +0.0) | 12.20 |
| 2023.12 | 151.1 | 146.4 | 114.2 | (120.5 projected, -3.4) | 9.60 |
| 2024.01 | 164.6 | 159.3 | 123.0 | (117.1 projected, -3.3) | 5.46 |
| 2024.02 | 171.8 (1) | 53.4 (2A) / 140.9 (2B) / 162.2 (2C) | (116.3 projected, -0.8) | (5.2) | |
| 2024.03 | (115.8 projected, -0.5) | ||||
| 2024.04 | (115.7 projected, -0.1) | ||||
| 2024.05 | (117.0 projected, +1.3) | ||||
| 2024.06 | (116.2 projected, -0.8) | ||||
| 2024.07 | (114.5 projected, -1.7) | ||||
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 high solar activity during the first weeks of 2024 has changed the outlook regarding solar max. The first peak in June 2023 currently has a less than 10% probability of being the actual solar max. The next candidate month is October 2023 (October 8-11 if zooming in on a specific date). The likelihood of October 2023 surpassing June 2023 is at least 50%. It is still likely that solar max will be sometime between October 2023 and March 2025.
--------------------------------------------------------------------------------------
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.
