The geomagnetic field was quiet to severe storm on March 23. Solar wind speed at SOHO ranged between 440 and 511 km/sec. The high latitude magnetometer at Andenes recorded quiet to major storm levels. Solar wind density and the total IMF field increased slowly after 08:30 at DSCOVR with solar wind density peaking at a very high level at 13:47 UT whereas the total IMF field peaked at 14:03 at 22 nT. The source of the disturbance is likely the relatively slow CME observed early on March 20. The Bz component of the IMF was strongly southwards after 17h UT resulting in severe geomagnetic storming. Early on March 24 very severe geomagnetic storming was recorded.
Solar flux density measured at 20h UT on 2.8 GHz was 151.1 - decreasing 13.0 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 138.18). The Potsdam WDC planetary A index was 59 (STAR Ap - based on the mean of three hour interval ap indices: 58.6). Three hour interval K indices: 12357567 (planetary), 12456445 (Boulder), 02245566 (Andenes).
The background x-ray flux is at the class B6 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 14 active regions using 2K resolution (SN: 274) and in 12 active regions using 1K resolution (SN: 193) SDO/HMI images.
Region 13256 [S22W02] developed further in the trailing
spot section and has polarity intermixing. C1 flares: C1.1 @ 01:29 UT
Region 13257 [S27E16] decayed slowly and lost the magnetic delta.
Region 13259 [S16E16] gained spots and has weak polarity intermixing.
Region 13260 [N23E19] was quiet and stable.
Region 13262 [S18E57] was quiet and stable.
Spotted regions not observed (or interpreted
differently) by SWPC:
S8370 [N25W23] was quiet and stable.
S8383 [N20E38] was quiet and stable.
S8387 [N17E12] developed further and was quiet.
S8388 [S20E68] was quiet and stable.
New region S8389 [N25W15] emerged with small spots.
New region S8390 [N15E85] rotated partly into view with a
mature spot.
New region S8391 [S11E53] emerged with tiny spots.
New region S8392 [S26E38] was observed with tiny spots in an
old plage area.
New region S8393 [N39E12] emerged with a tiny spot.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
March 21-23: 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]
A large southern hemisphere coronal hole (CH1136) was Earth facing on March 20-22. A trans equatorial coronal hole (CH1137) began to rotate across the central meridian on March 23 and then collapsed.
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.
Unsettled to very severe geomagnetic storm conditions are likely on March 24 due to CME effects. Quiet to active conditions are possible on March 25-26 due to CME and coronal hole effects.
| Coronal holes (1) | Coronal mass ejection (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 | ||||||||||
| S8366 | 2023.03.15 | S19W49 | |||||||||
| 13256 | 2023.03.16 2023.03.17 |
4 | 34 | 25 | S22W04 | 0230 | CSO | FHI |
 |
 |
area: 0440 location: S22W02 |
| S8370 | 2023.03.17 | 3 | 1 | N25W23 | 0008 | BXO |
 |
 |
|||
| 13257 | 2023.03.18 2023.03.18 |
2 | 13 | 6 | S27E14 | 0190 | HAX | CAO |
 |
 |
area: 0330 location: S27E16 |
| 13259 | 2023.03.18 2023.03.19 |
8 | 24 | 13 | S22E07 | 0020 | BXO | DRI |
 |
 |
location: S16E16 SWPC location is far off location: 0060 |
| 13258 | 2023.03.18 | N18W24 |
 |
location: N18W15 |
|||||||
| 13260 | 2023.03.18 2023.03.19 |
7 | 12 | 4 | N20E16 | 0140 | CSO | CSO |
 |
 |
area: 0200 location: N23E19 |
| S8376 | 2023.03.18 | S43W19 | |||||||||
| S8377 | 2023.03.19 | N24W01 | |||||||||
| S8378 | 2023.03.20 | N06W22 | |||||||||
| S8379 | 2023.03.20 | S03W51 | |||||||||
| S8380 | 2023.03.20 | S29W23 | |||||||||
| S8381 | 2023.03.20 | S42W01 | |||||||||
| S8383 | 2023.03.20 | 4 | 1 | N20E38 | 0010 | HRX |
 |
 |
|||
| S8384 | 2023.03.20 | S11W45 | |||||||||
| 13262 | 2023.03.21 2023.03.22 |
2 | 4 | 2 | S18E56 | 0130 | CAO | CAO |
 |
 |
area: 0190 location: S18E57 |
| S8386 | 2023.03.21 | N19W10 | |||||||||
| S8387 | 2023.03.22 | 21 | 13 | N17E12 | 0080 | DRI |
 |
 |
|||
| S8388 | 2023.03.22 | 2 | 1 | S20E68 | 0010 | HRX |
 |
 |
|||
| S8389 | 2023.03.23 | 9 | 5 | N25W15 | 0060 | DRO |
 |
||||
| S8390 | 2023.03.23 | 1 | N15E85 | 0080 | HSX |
 |
|||||
| S8391 | 2023.03.23 | 3 | 1 | S11E53 | 0004 | BXO |
 |
||||
| S8392 | 2023.03.23 | 3 | S26E38 | 0005 | AXX |
 |
|||||
| S8393 | 2023.03.23 | 1 | 1 | N39E12 | 0003 | AXX |
 |
||||
| Total spot count: | 23 | 134 | 73 | ||||||||
| Sunspot number: | 73 | 274 | 193 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 43 | 179 | 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): | 80 | 151 | 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 |
| 2021.08 | 77.7 | 79.7 | 22.0 | 35.4 (+4.0) | 6.19 |
| 2021.09 | 87.0 | 88.2 | 51.3 | 40.2 (+4.8) | 6.33 |
| 2021.10 | 88.9 | 88.3 | 37.4 | 45.2 (+5.0) | 7.38 |
| 2021.11 | 86.2 | 84.4 | 34.8 | 50.8 (+5.6) | 9.83 |
| 2021.12 | 103.0 | 99.8 | 67.5 | 55.9 (+5.1) | 6.40 |
| 2022.01 | 103.8 | 100.5 | 55.3 | 60.1 (+4.2) | 8.92 |
| 2022.02 | 109.1 | 106.5 | 60.9 | 64.7 (+4.6) | 10.46 |
| 2022.03 | 117.0 | 115.8 | 78.6 | 68.7 (+4.0) | 10.20 |
| 2022.04 | 130.8 | 131.7 | 84.0 | 73.0 (+4.3) | 11.79 |
| 2022.05 | 133.8 | 136.8 | 96.5 | 77.2 (+4.2) | 7.48 |
| 2022.06 | 116.1 | 119.8 | 70.3 | 80.9 (+3.7) | 8.20 |
| 2022.07 | 125.4 | 129.5 | 91.4 | 86.5 (+5.6) | 9.51 |
| 2022.08 | 114.2 | 117.1 | 74.6 | 92.3 (+5.8) | 10.92 |
| 2022.09 | 135.1 | 136.5 | 96.0 | (97.0 projected, +4.7) | 12.18 |
| 2022.10 | 133.5 | 132.7 | 95.4 | (100.2 projected, +3.2) | 11.16 |
| 2022.11 | 123.4 | 120.7 | 77.6 | (103.0 projected, +2.8) | 9.33 |
| 2022.12 | 147.9 | 143.4 | 113.1 | (107.8 projected, +4.8) | 10.99 |
| 2023.01 | 182.4 | 176.6 | 143.6 | (113.8 projected, +6.0) | 8.73 |
| 2023.02 | 167.2 | 163.2 | 110.9 | (118.9 projected, +5.1) | 14.48 (current SC25 peak) |
| 2023.03 | 159.3 (1) | 79.8 (2A) / 107.6 (2B) / 133.5 (2C) | (122.0 projected, +3.1) | (13.6) | |
| 2023.04 | (127.4 projected, +5.4) | ||||
| 2023.05 | (133.2 projected, +5.8) | ||||
| 2023.06 | (136.4 projected, +3.2) | ||||
| 2023.07 | (135.9 projected, -0.5) | ||||
| 2023.08 | (136.9 projected, +1.0) | ||||
| 2023.11 | (142.5 projected max SC25) | ||||
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: SIDC-SILSO.
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.
