The geomagnetic field was at quiet to unsettled levels on March 11 under the influence of effects from CH1274. A high speed stream associated with CH1275 appears to have reached Earth early on March 12. Solar wind speed at SOHO ranged between 417 and 562 km/sec, averaging 476 km/sec (-76 km/sec compared to the previous day). The high latitude magnetometer at Andenes recorded quiet to major levels. The above 10 MeV proton flux was slightly above background levels after the M1 flare in AR 14024 and returned to background levels early on March 12. The peak was at 19:50 UT at 0.54 pfu.
Solar flux density measured at 20h UT on 2.8 GHz was 161.4 - decreasing 12.0 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 194.02. In comparison SC24 peaked on June 28, 2014 at 145.50 while SC23 peaked on February 23, 2002 at 198.15. Current SC25 peak: 194.02 on September 10, 2024 (subtracting a baseline solar flux level of 65, this is +60.27% compared to the SC24 peak and -3.10% compared to the SC23 peak). The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.0). Three hour interval K indices: 22222213 (planetary), 22333523 (Boulder), 43332236 (Andenes).
The background x-ray flux is at the class C1 level (GOES 18).
At the time of counting spots (see image time), spots were observed in 15 active regions using 2K resolution (SN: 296) and in 12 active regions using 1K resolution (SN: 191) SDO/HMI images.
AR 14012 [S13W71] decayed slowly and quietly.
AR 14018 [S20E01] was mostly quiet and stable. C1 flares: C1.3 @
09:11 UT
AR 14019 [N06E18] developed slowly and is a compact region with a
magnetic delta. Flare activity was unimpressive. C1 flares: C1.8 @ 06:53,
C1.8 @ 10:31, C1.7 @ 10:42, C1.7 @ 12:19, C1.7 @ 13:44, C1.6 @ 13:49, C1.6 @
14:12, C1.5 @ 14:18, C1.3 @ 16:07 UT
AR 14020 [N19E38] was quiet and stable.
AR 14021 [S05E57] developed a small magnetic delta in the
southwestern part of the largest penumbra (and became a reversed polarities
group). An M flare is possible. C1 flares: C1.1 @ 04:11, C1.9 @ 21:56, C1.3
@ 23:11 UT
New AR 14022 [N08E47] emerged on March 10 with several spots and was
numbered the next day by SWPC. C1 flares: C1.6 @ 02:00, C1.7 @ 02:09, C1.1 @
02:36 UT
New AR 14023 [N25E59] rotated into view on March 10 with a mature
spot and received its NOAA number the next day.
New AR 14024 [N06W53] emerged on March 10 with a magnetic delta
forming quickly. SWPC noticed the spot group the next day. Spots are still
small and only immature penumbra is visible. The region was the most active
on the disk during the latter half of the day producing several impulsive
flares. Further M class flaring is
possible as long as the magnetic delta is present. C1 flares: C1.3 @ 12:01
UT
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S10871 [N11W07] developed slowly and quietly.
S10873 [S08W15] was quiet and stable.
S10880 [N18E67] rotated into view with a tiny spot. C1 flares: C1.2 @
04:55 UT
New region S10882 [S20E63] emerged with a few spots. C1 flares: C1.4
@ 18:06 UT
New region S10883 [S08E40] was observed with tiny spots in an old
plage area.
New region S10884 [N10E57] emerged with several spots. C1 flares:
C1.3 @ 08:55 UT
New region S10885 [N05W39] emerged with tiny spots.
An active region behind the southeast limb was the source of a C1.4 flare at 22:36 UT
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C2.6 | 05:51 | 14021 | GOES16 | ||
| C2.0 | 10:12 | 14019 | GOES16 | ||
| M1.1 | 13:04 | 14024 | GOES16 | weak proton enhancement | |
| C6.0 | 18:27 | 14024 | GOES16 | ||
| C7.2 | 19:16 | behind the southeast limb | GOES16 | ||
| C2.1 | 19:54 | 14019 | GOES16 | simultaneous flare in AR S10882 | |
| C2.2 | 20:38 | 14024 | GOES16 | ||
| C9.6 | 21:22 | 14024 | GOES16 | ||
| C2.0 | 21:42 | behind the southeast limb | GOES16 |
March 9-11: No obviously Earth directed CMEs.
[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 recurrent trans equatorial negative polarity coronal hole (CH1274) was Earth facing on March 5-7. A recurrent southern hemisphere negative polarity coronal hole (CH1275) rotated across the central meridian on March 9-10. A southern hemisphere negative polarity coronal hole (CH1276) will likely become Earth facing on March 13.
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 to fair.
The geomagnetic field is expected to be at quiet to active levels on March 12-14 due to effects from CH1275.
| 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 | ||||||||||
| 14011 | 2025.03.01 2025.03.02 |
S14W77 |
was AR S10846 location: S21W68 the SWPC location of this AR was at S19E04 on 2025.03.05, then SWPC moved the AR to the location of AR S10850 |
||||||||
| 14012 | 2025.03.01 2025.03.02 |
16 | 17 | 6 | S14W70 | 0130 | CAI | CAO |
 |
 |
was AR S10847 location: S13W71 area: 0100 |
| 14013 | 2025.03.01 2025.03.02 |
S04W74 | was AR S10848 | ||||||||
| 14016 | 2025.03.03 2025.03.04 |
S25W46 |
was AR S10858 location: S26W43 |
||||||||
| 14017 | 2025.03.04 2025.03.05 |
S05W26 |
was AR S10860 location: S04W21 |
||||||||
| S10863 | 2025.03.04 | N11W27 |
 |
||||||||
| 14018 | 2025.03.05 2025.03.05 |
6 | 22 | 8 | S20E01 | 0100 | CSO | CSO |
 |
 |
location: S20E27 area: 0210 |
| S10865 | 2025.03.06 | S06W55 | |||||||||
| 14019 | 2025.03.06 2025.03.07 |
9 | 33 | 12 | N07E18 | 0180 | DAC | DAC |
 |
 |
beta-delta was AR S10866 area: 0450 |
| 14020 | 2025.03.08 2025.03.09 |
1 | 2 | 1 | N19E36 | 0050 | HSX | HSX |
 |
 |
was AR S10870 location: N19E38 area: 0110 |
| S10871 | 2025.03.08 | 6 | 4 | N11W07 | 0020 | CRO |
 |
 |
|||
| S10872 | 2025.03.08 | S14W43 | |||||||||
| S10873 | 2025.03.08 | 7 | S08W15 | 0010 | BXO |
 |
 |
||||
| S10874 | 2025.03.08 | S04E09 |
 |
||||||||
| 14021 | 2025.03.09 2025.03.10 |
6 | 18 | 10 | S06E57 | 0080 | CAO | DAC |
 |
 |
beta-delta was AR S10876 area: 0180 location: S05E57 reversed polarities |
| S10877 | 2025.03.09 | S13W10 | |||||||||
| 14024 | 2025.03.10 2025.03.11 |
5 | 8 | 4 | N05W54 | 0020 | CRO | DRI |
 |
 |
beta-delta was AR S10878 location: N05W53 area: 0040 |
| 14023 | 2025.03.10 2025.03.11 |
1 | 1 | 1 | N25E58 | 0030 | HSX | HSX |
 |
 |
was AR S10879 area: 0100 |
| S10880 | 2025.03.10 | 1 | N18E67 | 0002 | AXX |
 |
 |
||||
| 14022 | 2025.03.10 2025.03.11 |
4 | 13 | 8 | N08E47 | 0030 | CRO | DRI |
 |
 |
was AR S10881 area: 0060 |
| S10882 | 2025.03.11 | 3 | 2 | S20E63 | 0030 | CRO |
 |
beta-delta? | |||
| S10883 | 2025.03.11 | 4 | 1 | S08E40 | 0010 | BXO |
 |
||||
| S10884 | 2025.03.11 | 9 | 5 | N10E57 | 0050 | DRI |
 |
||||
| S10885 | 2025.03.11 | 2 | N05W39 | 0005 | BXO |
 |
|||||
| Total spot count: | 48 | 146 | 72 | ||||||||
| Sunspot number: | 128 | 296 | 192 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 79 | 186 | 112 | (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): | 141 | 163 | 154 | ||||||||
| 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 |
| 2023.09 | 154.4 | 156.0 | 134.2 | 124.0 (-0.3) | 14.26 |
| 2023.10 | 142.8 | 141.9 | 99.9 | 124.8 (+0.8) | 8.16 |
| 2023.11 | 153.5 | 150.2 | 107.1 | 127.9 (+3.1) | 12.20 |
| 2023.12 | 151.1 | 146.4 | 113.5 | 129.5 (+1.6) | 9.60 |
| 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 | 152.7 (+3.6) | 10.24 |
| 2024.07 | 196.6 | 203.0 | 196.8 | 154.9 (+2.3) | 7.13 |
| 2024.08 | 246.1 (cycle peak) |
252.2 | 216.0 (SC25 peak) | 156.7 (+1.8) | 15.96 |
| 2024.09 | 195.7 | 197.8 | 141.1 | (159.5 projected, +2.8) | 15.36 |
| 2024.10 | 221.0 | 219.6 | 166.4 | (160.6 projected, +1.1) | 18.99 |
| 2024.11 | 199.6 | 195.3 | 152.5 | (158.0 projected, -2.6) | 9.33 |
| 2024.12 | 197.3 | 191.2 | 154.5 | (154.2 projected, -3.8) | 8.42 |
| 2025.01 | 190.3 | 184.2 | 137.0 | (148.7 projected, -5.5) | 13.17 |
| 2025.02 | 184.2 | 179.7 | 154.7 | (140.2 projected, -8.5) | 14.42 |
| 2025.03 | 153.3 (1) | 39.9 (2A) / 112.5 (2B) / 171.9 (2C) | (133.8 projected, -6.4) | (11.9) | |
| 2025.04 | (129.2 projected, -4.6) | ||||
| 2025.05 | (123.9 projected, -5.3) | ||||
| 2025.06 | (119.0 projected, -4.9) | ||||
| 2025.07 | (114.9 projected, -4.1) | ||||
| 2025.08 | (110.2 projected, -4.7) | ||||
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 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). Currently all 365 days smoothed indices are still indicating that a peak occurred on October 12 or 13, 2024. Should sunspot activity decrease even further then there is a possibility that the peak may have taken place in September 2024. Any peak outside of September-October 2024 appears unlikely. The 365 days average solar flux is likely to max out ~2% below the peak of solar cycle 23. The maximum 365d smoothed solar flux of SC23 and SC25 are similar, however, sunspot numbers were significantly lower during SC25 compared to SC23.
--------------------------------------------------------------------------------------
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.
