The geomagnetic field was quiet to minor storm on April 27, after noon under the influence of an unexpected CME related disturbance. The high latitude magnetometer at Andenes recorded quiet to minor storm levels.
Solar flux density measured at 20h UT on 2.8 GHz was 141.5 - decreasing 7.2 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 94.24). The Potsdam WDC planetary A index was 18 (STAR Ap - based on the mean of three hour interval ap indices: 17.9). Three hour interval K indices: 22115434 (planetary), 22214434 (Boulder), 32115555 (Andenes).
The background x-ray flux is at the class B7 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 15 active regions using 2K resolution (SN: 255) and in 13 active regions using 1K resolution (SN: 179) SDO/HMI images.
Region 12993 [N20W71] decayed slowly and
quietly.
Region 12994 [N14W67] decayed slowly and was mostly quiet. C1 flares:
C1.3 @ 04:05 UT
Region 12995 [N14W38] was mostly quiet and stable. C1 flares: C1.1 @
19:11 UT
Region 12996 [N25W20] decayed slowly and produced several C flares.
Region 12997 [N12E09] developed slowly and was quiet.
Region 12998 [S20E25] was quiet and stable. Note that SWPC has
assigned a new number (12999) to the region due to the faulty initial
location of AR 12998. For data consistency the original number is used in
this report.
Region 13000 [S17E58] decayed slowly and quietly losing mature
penumbra.
Region 13001 [S31E61] was quiet and stable.
Spotted regions not observed (or interpreted
differently) by SWPC:
S7510 [N25W02] was quiet and stable.
S7518 [S10E48] was quiet and stable.
S7521 [S28E08] was quiet and stable.
S7524 [N14E40] was quiet and stable.
S7525 [N31E65] developed slowly and quietly.
New region S7529 [S14E78] rotated into view with a few spots.
New region S7530 [S13E12] emerged with a tiny spot.
A region behind the southeast limb produced a C1.0 flare at 00:52 UT.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C3.3 | 08:40 | N28W11 | 12996 | GOES16 | |
| C2.9 | 09:06 | 12994 | GOES16 | ||
| C2.0 | 10:48 | S29E73 | 13001 | GOES16 | |
| C7.7/1F | 14:54 | N26W16 | 12996 | GOES16 | LDE, partial halo CME |
April 25-26: No obviously Earth directed CMEs
were observed in available LASCO imagery.
April 27: A partial halo CME was observed after the C7.7 long
duration event in AR 12996. The CME could reach Earth on April 30 and cause
unsettled to mi0nor 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 recurrent southern hemisphere coronal hole (CH1076) was Earth facing on April 26-27.
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.
Quiet to active conditions are likely on April 28 due to CME effects and quiet to minor storm on April 29 due to effects from CH1076. Unsettled to minor storm conditions are possible on April 30 and May 1 due to the April 27 CME.
| 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 | ||||||||||
| 12993 | 2022.04.16 2022.04.16 |
3 | 5 | 3 | N20W71 | 0180 | HAX | CAO |
 |
 |
|
| 12994 | 2022.04.16 2022.04.16 |
11 | 18 | 12 | N15W66 | 0320 | EKO | EKO |
 |
 |
area: 0650 location: N13W67 |
| 12995 | 2022.04.18 2022.04.19 |
1 | 13 | 5 | N14W38 | 0120 | HSX | CHO |
 |
 |
area: 0280 |
| 12996 | 2022.04.19 2022.04.20 |
6 | 2 | N25W25 | 0012 | BXO |
 |
 |
location: N25W20 | ||
| S7510 | 2022.04.21 | 3 | N25W02 | 0003 | BXO |
 |
 |
||||
| 12997 | 2022.04.22 2022.04.23 |
4 | 23 | 11 | N12E13 | 0030 | CRO | ERI |
 |
 |
location: N12E09 area: 0070 |
| S7512 | 2022.04.22 | N38W41 | |||||||||
| S7513 | 2022.04.22 | S26W50 |
 |
||||||||
| S7514 | 2022.04.22 | S15W43 | |||||||||
| S7515 | 2022.04.22 | S19W26 |
 |
||||||||
| 12998 | 2022.04.23 2022.04.23 |
16 | 5 | S19W43 | 0180 | CSO |
 |
 |
SWPC location way off location: S20E25 |
||
| 12999 | 2022.04.25 | 4 | S20E23 | 0100 | HAX | SWPC renumber of AR 12998 | |||||
| S7517 | 2022.04.24 | S18W37 | |||||||||
| S7518 | 2022.04.25 | 3 | 1 | S10E48 | 0005 | AXX |
 |
 |
|||
| 13000 | 2022.04.25 2022.04.26 |
1 | 3 | 2 | S16E56 | 0040 | HSX | HRX |
 |
 |
location: S17E58 area: 0020 |
| 13001 | 2022.04.25 2022.04.26 |
1 | 2 | 1 | S26E58 | 0120 | HSX | HSX |
 |
 |
location: S31E61 area: 0170 |
| S7521 | 2022.04.25 | 3 | 1 | S28E08 | 0005 | AXX |
 |
 |
|||
| S7523 | 2022.04.26 | S05W44 |
 |
||||||||
| S7524 | 2022.04.26 | 3 | 2 | N14E40 | 0010 | AXX |
 |
 |
|||
| S7525 | 2022.04.26 | 3 | 2 | N31E65 | 0006 | BXO |
 |
 |
|||
| S7526 | 2022.04.26 | S15E45 |
 |
||||||||
| S7527 | 2022.04.26 | N25E34 |
 |
||||||||
| S7528 | 2022.04.27 | S15W66 |
 |
||||||||
| S7529 | 2022.04.27 | 3 | 2 | S14E78 | 0015 | DRO |
 |
||||
| S7530 | 2022.04.27 | 1 | S13E12 | 0002 | AXX |
 |
|||||
| Total spot count: | 25 | 105 | 49 | ||||||||
| Sunspot number: | 95 | 255 | 179 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 63 | 149 | 93 | (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): | 105 | 128 | 143 | ||||||||
| 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) | 10.20 |
| 2022.04 | 131.4 (1) | 67.5 (2A) / 75.0 (2B) / 97.8 (2C) | (75.4 projected, +5.2) | (11.5) | |
| 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.
