The geomagnetic field was quiet to unsettled on February 20. Solar wind speed at SOHO ranged between 315 and 486 km/sec. The high latitude magnetometer at Andenes recorded quiet to active levels. A solar wind shock was recorded at 09:45 UT at SOHO, the arrival of the February 17 CME. Initially the CME caused only a mild disturbance. The Bz component of the interplanetary magnetic field has been southward over longer intervals early on February 21 causing an increase in geomagnetic activity.
Solar flux density measured at 20h UT on 2.8 GHz was 159.8 - decreasing 20.4 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 133.86). The Potsdam WDC planetary A index was 7 (STAR Ap - based on the mean of three hour interval ap indices: 6.9). Three hour interval K indices: 00232222 (planetary), ******** (Boulder), 00122343 (Andenes).
The background x-ray flux was 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: 232) and in 11 active regions using 1K resolution (SN: 165) SDO/HMI images.
Region 13217 [S12W83] was quiet and stable.
Region 13220 [S13W67] was quiet and stable.
Region 13226 [N10W63] decayed further losing spots and area.
Region 13229 [N26E20] decayed slowly and lost the magnetic delta. C1
flares: C1.9 @ 12:51, C1.9 @ 13:00, C1.9 @ 22:03 UT
Region 13230 [S22E46] was quiet and stable.
Region 13231 [N20W51] was mostly quiet and stable.
New region 13232 [N09W80] emerged on February 19 and decayed on
February 20 when it was numbered by SWPC.
New region 13233 [N14E02] emerged on February 19 with SWPC numbering
the region the following day.
New region 13234 [N25E72] rotate into view and could have a magnetic
delta structure in the leading spot section. C1 flares: C1.9 @ 23:51 UT
Spotted regions not observed (or interpreted
differently) by SWPC:
S8294 [N02W51] decayed slowly and quietly.
S8295 [S22E15] developed slowly as new flux
emerged.
New region S8298 [N12E45] emerged with tiny spots.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C3.0 | 00:20 | 13229 | GOES16 | ||
| C2.8 | 01:25 | 13231 | GOES16 | ||
| C2.8 | 02:16 | 13226 | GOES16 | ||
| C2.4 | 02:24 | 13231 | GOES16 | ||
| C2.0 | 02:42 | 13232 | GOES16 | ||
| C2.1 | 04:18 | 13232 | GOES16 | ||
| C3.3/1F | 04:51 | N20W42 | 13231 | GOES16 | |
| C5.5 | 06:08 | 13231 | GOES16 | ||
| C4.4 | 06:47 | 13234 | GOES16 | ||
| C7.1 | 07:02 | 13226 | GOES16 | ||
| C2.2 | 08:57 | 13229 | GOES16 | ||
| C2.4 | 09:28 | 13234 | GOES16 | ||
| C2.4 | 09:59 | 13234 | GOES16 | ||
| C2.5 | 10:37 | 13225 | GOES16 | attributed to smaller, simultaneous flare in AR 13226 by SWPC | |
| M4.4 | 14:58 | N25E75 | 13234 | GOES16 | |
| C3.1 | 16:26 | 13229 | GOES16 | ||
| C5.4 | 17:43 | 13229 | GOES16 | ||
| C2.8 | 19:12 | 13229 | GOES16 | ||
| C2.8 | 22:23 | 13234 | GOES16 | ||
| C2.4 | 22:34 | 13234 | GOES16 | ||
| C2.0 | 23:05 | 13234 | GOES16 | ||
| C2.1 | 23:27 | 13234 | GOES16 |
February 18-20: 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 southern hemisphere coronal hole (CH1131) rotated across the central meridian on February 17.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle and high latitudes is poor to fair. Propagation on long distance northeast-southwest paths is poor.
Quiet to minor storm is expected on February 21 due to the February 17 CME. Quiet to unsettled conditions are likely on February 22-23 due to effects from CH1131.
| 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 | ||||||||||
| 13217 | 2023.02.07 2023.02.08 |
2 | 1 | 1 | S12W85 | 0130 | HSX | HHX |
 |
 |
location: S12W83 area: 0270 |
| 13220 | 2023.02.09 2023.02.09 |
1 | 1 | 1 | S13W69 | 0120 | HSX | HSX |
 |
 |
area: 0220 location: S13W67 |
| 13221 | 2023.02.09 2023.02.09 |
N19W75 |
location: N13W69 |
||||||||
| 13224 | 2023.02.11 2023.02.11 |
N22W76 |
location: N22W71 |
||||||||
| 13228 | 2023.02.11 2023.02.13 |
S24W84 | |||||||||
| S8273 | 2023.02.11 | N27W58 | |||||||||
| S8274 | 2023.02.11 | N22W50 | |||||||||
| 13226 | 2023.02.12 2023.02.13 |
8 | 11 | 4 | N10W60 | 0280 | CKO | CKO |
 |
 |
area: 0340 |
| 13227 | 2023.02.12 2023.02.13 |
S03W60 |
 |
location: S04W54 | |||||||
| 13231 | 2023.02.13 2023.02.19 |
8 | 15 | 9 | N21W52 | 0050 | DSO | DRI |
 |
 |
|
| S8280 | 2023.02.15 | S37W46 | |||||||||
| S8281 | 2023.02.15 | S11W48 | |||||||||
| S8283 | 2023.02.15 | N12W37 |
 |
||||||||
| 13229 | 2023.02.16 2023.02.16 |
16 | 47 | 25 | N26E19 | 0310 | EKC | EAI |
 |
 |
beta-gamma location: N26E20 area: 0430 |
| S8286 | 2023.02.17 | S10E14 |
 |
||||||||
| 13230 | 2023.02.17 2023.02.18 |
3 | 6 | 4 | S23E44 | 0110 | HSX | HSX |
 |
 |
area: 0220 |
| S8288 | 2023.02.17 | N20W21 | |||||||||
| S8289 | 2023.02.18 | S17W21 | |||||||||
| 13233 | 2023.02.18 2023.02.20 |
1 | 6 | 1 | N14W01 | 0010 | AXX | CRO |
 |
 |
location: N14E02 |
| S8291 | 2023.02.18 | N28W31 | |||||||||
| 13232 | 2023.02.19 2023.02.20 |
1 | 1 | 1 | N10W79 | 0010 | HRX | HRX |
 |
 |
|
| S8293 | 2023.02.19 | N12W37 |
 |
||||||||
| S8294 | 2023.02.19 | 1 | N01W52 | 0001 | AXX |
 |
 |
||||
| S8295 | 2023.02.19 | 10 | 1 | S22E15 | 0015 | BXO |
 |
 |
|||
| S8296 | 2023.02.19 | S48E02 |
 |
||||||||
| S8298 | 2023.02.20 | 2 | 1 | N12E45 | 0005 | BXO |
 |
||||
| 13234 | 2023.02.20 2023.02.20 |
5 | 11 | 7 | N24E76 | 0080 | DAI | EAI |
 |
area: 0130 location: N25E72 was AR S8299 |
|
| Total spot count: | 45 | 112 | 55 | ||||||||
| Sunspot number: | 135 | 232 | 165 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 93 | 161 | 104 | (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): | 149 | 128 | 132 | ||||||||
| 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 (solar max) | 7.88 |
| 2017.09 | 91.3 | 92.3 | 43.6 | 18.2 (-1.3) | 18.22 (cycle 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 |
| 2021.07 | 81.0 | 83.6 | 34.3 | 31.4 (+3.8) | 5.51 |
| 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 | (92.4 projected, +5.9) | 10.92 |
| 2022.09 | 135.1 | 136.5 | 96.0 | (97.4 projected, +5.0) | 12.18 |
| 2022.10 | 133.5 | 132.7 | 95.4 | (100.5 projected, +3.1) | 11.16 |
| 2022.11 | 123.4 | 120.7 | 77.6 | (103.4 projected, +2.9) | 9.33 |
| 2022.12 | 147.9 | 143.4 | 113.1 | (108.2 projected, +4.8) | 10.99 |
| 2023.01 | 182.4 | 176.6 | 143.6 | (114.2 projected, +6.0) | 8.73 |
| 2023.02 | 171.2 (1) | 92.0 (2A) / 128.8 (2B) / 152.3 (2C) | (119.2 projected, +5.0) | (10.8) | |
| 2023.03 | (122.3 projected, +3.1) | ||||
| 2023.04 | (127.7 projected, +5.4) | ||||
| 2023.05 | (133.5 projected, +5.8) | ||||
| 2023.06 | (136.8 projected, +3.3) | ||||
| 2023.07 | (136.3 projected, -0.5) | ||||
| 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.
