The geomagnetic field was quiet on February 29. Solar wind speed at SOHO ranged between 368 and 450 km/sec. The high latitude magnetometer at Andenes recorded very quiet 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 164.1 - increasing 21.5 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 157.44. 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 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.3). Three hour interval K indices: 00112101 (planetary), 10222211 (Boulder), 00011000 (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 11 active regions using 2K resolution (SN: 266) and in 9 active regions using 1K resolution (SN: 164) SDO/HMI images.
Region 13590 [N18W67] produced low level C
flares and lost most of the trailing
spots. There's still a large magnetic delta structure in the eastern part of
the huge leading penumbral area. A major flare is
possible. C1 flares: C1.5 @ 06:33, C1.8 @ 07:39, C1.2 @ 11:01, C1.5 @ 12:13.
C1.8 @ 20:06, C1.7 @ 20:42 UT
Region 13591 [S36W02] was quiet and stable.
Region 13592 [S14W04] was quiet and stable.
Region 13594 [N05W13] was mostly quiet and stable. C1 flares: C1.6 @
15:00 UT
Region 13595 [N20W10] decayed slightly and was quiet.
Region 13596 [N18E23] was mostly quiet and stable. C1 flares: C1.6 @
12:34 UT
Region 13597 [N07E01] decayed slowly and quietly.
New region 13598 [S13W19] emerged on February 28 and was numbered the
next day by SWPC as development continued.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S9453 [S16E10] was quiet and stable.
S9462 [N13E35] was quiet and stable.
New region S9466 [S15E83] rotated partially into view and could
produce C flares. C1 flares: C1.3 @ 13:05, C1.9 @ 18:14, C1.8 @ 20:22 UT
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C4.0 | 05:13 | southeast limb | S9466 | GOES18 | incorrectly attributed to AR 13590 by SWPC |
| C2.3 | 13:34 | southeast limb | S9466 | GOES16 | |
| C2.5 | 16:57 | 13590 | GOES16 | simultaneous flare in AR S9466 | |
| C2.4 | 19:30 | southeast limb | S9466 | GOES16 | |
| C2.4 | 21:03 | 13590 | GOES16 | simultaneous flare in AR S9466 | |
| C2.4 | 21:50 | 13590 | GOES16 | ||
| C2.2 | 22:08 | 13590 | GOES16 | simultaneous flare in AR S9466 | |
| C3.8 | 00:01 | 13590 | GOES16 | simultaneous flare in AR S9466 |
February 27, 29: No obviously Earth directed CMEs were observed.
February 28: A C5 flare in AR S9453 at 09:09 UT was associated with a
partial halo CME. The CME could cause a weak disturbance on March 2-3.
[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 fair. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet on February March 1-3 with a chance of unsettled and active intervals on March 2-3 should the February 28 CME reach Earth.
| 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 | ||||||||||
| 13590 | 2024.02.18 2024.02.18 |
12 | 27 | 14 | N18W65 | 1000 | FKC | EKC |
 |
 |
beta-gamma-delta location: N18W67 |
| 13591 | 2024.02.22 2024.02.23 |
1 | 4 | 1 | S36W04 | 0090 | HSX | CSO |
 |
 |
location: S36W02 |
| 13592 | 2024.02.22 2024.02.23 |
27 | 11 | S13W18 | 0040 | BXO |
 |
 |
location: S14W04 SWPC location is a copy of that of AR 13598 |
||
| 13594 | 2024.02.22 2024.02.23 |
1 | 8 | 3 | N05W13 | 0010 | HRX | HRX |
 |
 |
area: 0020 |
| 13595 | 2024.02.23 2024.02.24 |
12 | 32 | 19 | N20W10 | 0320 | DKO | EAO |
 |
 |
|
| S9452 | 2024.02.23 | S11W19 | |||||||||
| S9453 | 2024.02.24 | 5 | S16E10 | 0007 | BXO |
 |
 |
||||
| S9454 | 2024.02.24 | N08W00 | |||||||||
| S9457 | 2024.02.25 | N22W21 |
 |
||||||||
| 13596 | 2024.02.25 2024.02.26 |
6 | 16 | 10 | N18E24 | 0110 | CAO | DAO |
 |
 |
location: N18E23 |
| S9459 | 2024.02.27 | S23W33 |
 |
||||||||
| 13597 | 2024.02.28 2024.02.28 |
4 | 10 | 4 | N07E02 | 0010 | BXO | CRO |
 |
 |
area: 0020 location: N07E01 |
| S9462 | 2024.02.28 | 2 | 1 | N13E35 | 0003 | AXX |
 |
 |
|||
| S9463 | 2024.02.28 | N33W06 | 0005 | AXX |
 |
||||||
| 13598 | 2024.02.28 2024.02.29 |
1 | 23 | 11 | S13W18 | 0010 | HRX | DAI |
 |
 |
location: S13W19 area: 0150 |
| S9466 | 2024.02.29 | 2 | S15E83 | 0030 | CRO |
 |
|||||
| Total spot count: | 37 | 156 | 74 | ||||||||
| Sunspot number: | 107 | 266 | 164 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 78 | 195 | 113 | (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): | 118 | 146 | 131 | ||||||||
| 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 |
| 2022.07 | 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 | 172.5 | 168.3 | 116.9 (2A/2B) / 140.6 (2C) | (116.3 projected, -0.8) | 5.4 |
| 2024.03 | (1) | (2A/2B) / 140.6 (2C) | (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) | ||||
| 2024.08 | (113.1 projected, -1.4) | ||||
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
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.
