The geomagnetic field was quiet to active on April 11 due to a high speed stream from CH1072. The high latitude magnetometer at Andenes recorded quiet to minor storm levels.
Solar flux density measured at 20h UT on 2.8 GHz was 98.7 - decreasing 11.7 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 91.55). The Potsdam WDC planetary A index was 11 (STAR Ap - based on the mean of three hour interval ap indices: 10.6). Three hour interval K indices: 44322121 (planetary), 43332331 (Boulder), 53342343 (Andenes).
The background x-ray flux is at the class B3 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 7 active regions using 2K resolution (SN: 93) and in 5 active regions using 1K resolution (SN: 59) SDO/HMI images.
Region 12985 [S22W32] was quiet and stable.
Region 12987 [S31W07] reemerged with a tiny spot.
New region 12988 [N15E51] emerged on April 10 and was numbered the
next day by SWPC as the region developed slowly.
Spotted regions not observed (or interpreted
differently) by SWPC:
S7479 [N14W87] developed slowly as it rotated
to the northwest limb.
S7483 [S13W07] was mostly quiet and stable. A sigmoid shaped filament
in the southern part of the region erupted early in the day and was recorded
as a long duration C1.6 event peaking at 05:21 UT.
S7484 [N23W18] decayed slowly and quietly.
New region S7489 [N35E12] emerged before noon with a couple of
tiny spots, then decayed slowly.
AR 12978 behind the southwest limb was the likely source of a long duration C1.5 event that started late in the day and peaked at 00:07 UT on April 12. There was a simultaneous event in AR S7479 at the northwest limb.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C4.9 | 02:41 | 12978 | GOES16 |
April 9-10: No obviously Earth directed CMEs
were observed in available LASCO imagery.
April 11: AR S7483 was the source of a C1.6 LDE associated with a
symmetrical full halo CME. The CME will likely reach Earth sometimes between
noon on April 13 and 06 UT on April 14 and cause unsettled to major storm
conditions.
[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 trans equatorial coronal hole (CH1073) could rotate across the central meridian on April 12-13.
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.
Quiet conditions are likely on April 12 and most of April 13. The April 11 CME could cause unsettled to major storm conditions once it reaches Earth, probably after noon on April 13. The disturbance could continue on April 14 and 15, gradually weakening. A high speed stream associated with CH1073 could cause quiet to minor storm conditions on April 15-17.
| 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 | ||||||||||
| 12982 | 2022.03.29 2022.04.01 |
S22W86 | |||||||||
| 12983 | 2022.03.30 2022.04.02 |
1 | N20W83 | 0010 |
 |
spotless rotated out of view |
|||||
| 12985 | 2022.04.02 2022.04.03 |
4 | 2 | S20W37 | 0010 | BXO |
 |
 |
location: S22W32 |
||
| S7479 | 2022.04.04 | 1 | N14W87 | 0020 | HRX |
 |
 |
||||
| 12987 | 2022.04.04 2022.04.07 |
1 | 1 | S31W05 | 0004 | AXX |
 |
||||
| S7481 | 2022.04.06 | S25E04 |
 |
||||||||
| S7483 | 2022.04.06 | 2 | 1 | S13W07 | 0005 | AXX |
 |
 |
|||
| S7484 | 2022.04.07 | 5 | 1 | N23W18 | 0007 | AXX |
 |
 |
|||
| S7485 | 2022.04.07 | N27W31 | |||||||||
| S7486 | 2022.04.08 | N33W48 | |||||||||
| 12988 | 2022.04.10 2022.04.11 |
3 | 9 | 4 | N15E49 | 0010 | BXO | BXO |
 |
 |
area: 0020 location: N15E51 |
| S7488 | 2022.04.10 | S12E50 |
 |
||||||||
| S7489 | 2022.04.11 | 1 | N35E12 | 0002 | AXX |
 |
 |
||||
| Total spot count: | 4 | 23 | 9 | ||||||||
| Sunspot number: | 24 | 93 | 59 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 4 | 26 | 9 | (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): | 26 | 51 | 47 | ||||||||
| 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 |
| 2020.08 | 71.6 | 73.4 | 7.5 | 9.5 (+0.5) | 5.68 |
| 2020.09 | 70.7 | 71.4 | 0.7 | 10.5 (+1.0) | 8.59 |
| 2020.10 | 74.6 | 74.2 | 14.6 | 11.9 (+1.4) | 6.13 |
| 2020.11 | 89.9 | 88.0 | 34.5 | 13.6 (+1.7) | 4.77 |
| 2020.12 | 86.9 | 84.2 | 23.1 | 15.3 (+1.7) | 4.72 |
| 2021.01 | 76.0 | 73.6 | 10.4 | 17.3 (+2.0) | 4.39 |
| 2021.02 | 74.3 | 72.4 | 8.2 | 19.0 (+1.7) | 9.50 |
| 2021.03 | 76.0 | 75.2 | 17.2 | 21.7 (+2.7) | 10.17 |
| 2021.04 | 75.9 | 76.4 | 24.5 | 24.8 (+3.1) | 8.40 |
| 2021.05 | 75.3 | 77.1 | 21.2 | 25.8 (+1.0) | 6.50 |
| 2021.06 | 79.4 | 81.8 | 25.0 | 27.7 (+1.9) | 5.52 |
| 2021.07 | 81.0 | 83.6 | 34.3 | 31.4 (+3.7) | 5.51 |
| 2021.08 | 77.7 | 79.7 | 22.0 | 35.3 (+3.9) | 6.19 |
| 2021.09 | 87.0 | 88.2 | 51.3 | 40.0 (+4.7) | 6.33 |
| 2021.10 | 88.9 | 88.3 | 38.1 | (44.9 projected, +4.9) | 7.38 |
| 2021.11 | 86.2 | 84.4 | 35.0 | (50.5 projected, +5.6) | 9.83 |
| 2021.12 | 103.0 | 99.8 | 67.6 | (56.4 projected, +5.9) | 6.40 |
| 2022.01 | 103.8 | 100.5 | 54.0 | (60.0 projected, +3.6) | 8.92 |
| 2022.02 | 109.1 | 106.5 | 59.7 | (64.8 projected, +4.8) | 10.46 |
| 2022.03 | 117.0 | 115.8 | 78.3 | (70.2 projected, +5.4) | 10.1 |
| 2022.04 | 120.4 (1) | 25.0 (2A) / 68.1 (2B) / 87.0 (2C) | (75.4 projected, +5.2) | (12.5) | |
| 2022.05 | (81.8 projected, +6.4) | ||||
| 2022.06 | (87.7 projected, +5.9) | ||||
| 2022.07 | (94.9 projected, +7.2) | ||||
| 2022.08 | (101.6 projected, +6.7) | ||||
| 2022.09 | (106.6 projected, +5.0) | ||||
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.
