The geomagnetic field was quiet to minor storm on May 28 due to a high speed stream associated with CH1080. The high latitude magnetometer at Andenes recorded quiet to major storm levels.
Solar flux density measured at 20h UT on 2.8 GHz was 101.8 - decreasing 7.2 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 99.55). The Potsdam WDC planetary A index was 22 (STAR Ap - based on the mean of three hour interval ap indices: 22.0). Three hour interval K indices: 55532112 (planetary), 46632313 (Boulder), 56543113 (Andenes).
The background x-ray flux is at the class B2 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 8 active regions using 2K resolution (SN: 109) and in 4 active regions using 1K resolution (SN: 50) SDO/HMI images.
Region 13019 [N12W45] decayed slowly and quietly.
Region 13020 [S27W21] decayed with only tiny spots still visible.
Region 13021 [N12W10] decayed slowly and was unstable. C1
flares: C1.8 @ 19:04 UT
Region 13022 [S08E03] was quiet and stable.
Region 13023 [S13E26] gained a few spots and was quiet.
Region 13024 [S33E31] was quiet and stable.
Spotted regions not observed (or interpreted
differently) by SWPC:
S7595 [N28W37] was mostly quiet and stable.
S7596 [N20E12] was quiet and stable.
AR 13014 behind the northwest limb was the likely source of a C1.3 flare at 06:46 UT. While there was simultaneous activity related to a filament eruption in the northeast quadrant, that minor activity extended longer in time than the flare.
Many small filament eruptions were observed during the day. The most interesting began near 05:55 UT in SDO/AIA imagery to the west of AR 13024, then expanded westwards and northwards (slightly affecting the western part of AR 13023). This eruption may have been the source of a CME observed off the southeast limb with faint components extending into the southwest and northeast limbs. If the CME reaches Earth it will likely be on May 31. A much more impressive CME was observed beginning at 15:24 UT in LASCO C2 imagery with the first extensions noted over the south pole and the southeast limb. The likely source is an event in an active region a few days behind the southeast limb. Weak type II and IV radio sweeps recorded around 16h UT may have had the same source as the CME.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
May 26-28: No obviously Earth directed CMEs were observed in available LASCO imagery.
[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 (CH1080) rotated across the central meridian on May 24-26.
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 May 29 due to a high speed stream associated with CH1080 becoming quiet to unsettled on May 30-31.
| 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 | ||||||||||
| 13016 | 2022.05.15 2022.05.16 |
S19W89 | location: S18W81 | ||||||||
| 13019 | 2022.05.18 2022.05.19 |
1 | N14W50 | 0001 | AXX |
 |
 |
||||
| S7580 | 2022.05.20 | S14W47 | |||||||||
| 13020 | 2022.05.20 2022.05.22 |
4 | S21W23 | 0004 | AXX |
 |
 |
location: S27W21 | |||
| 13021 | 2022.05.21 2022.05.22 |
1 | 3 | N13W10 | 0000 | AXX | BXO |
 |
 |
area: 0007 | |
| S7585 | 2022.05.21 | N13W30 | |||||||||
| S7587 | 2022.05.22 | N32W49 | |||||||||
| 13022 | 2022.05.23 2022.05.24 |
3 | 1 | S08E01 | 0006 | BXO |
 |
 |
|||
| 13023 | 2022.05.24 2022.05.25 |
2 | 11 | 5 | S13E25 | 0110 | HAX | CAO |
 |
 |
area: 0210 |
| 13024 | 2022.05.24 2022.05.25 |
1 | 1 | 1 | S33E31 | 0070 | HSX | HSX |
 |
 |
|
| S7594 | 2022.05.25 | S20W31 | |||||||||
| S7595 | 2022.05.27 | 3 | 3 | N28W37 | 0010 | BXO |
 |
 |
|||
| S7596 | 2022.05.27 | 3 | N20E12 | 0005 | AXX |
 |
 |
||||
| S7597 | 2022.05.27 | S37W27 |
 |
||||||||
| Total spot count: | 4 | 29 | 10 | ||||||||
| Sunspot number: | 34 | 109 | 50 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 14 | 39 | 20 | (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): | 37 | 60 | 40 | ||||||||
| 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 |
| 2020.10 |
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 | 27.6 (+1.8) | 5.52 |
| 2021.07 | 81.0 | 83.6 | 34.3 | 31.3 (+3.7) | 5.51 |
| 2021.08 | 77.7 | 79.7 | 22.0 | 35.3 (+4.0) | 6.19 |
| 2021.09 | 87.0 | 88.2 | 51.3 | 40.0 (+4.7) | 6.33 |
| 2021.10 | 88.9 | 88.3 | 37.4 | 45.0 (+5.0) | 7.38 |
| 2021.11 | 86.2 | 84.4 | 34.8 | (50.0 projected, +5.0) | 9.83 |
| 2021.12 | 103.0 | 99.8 | 67.5 | (55.8 projected, +5.8) | 6.40 |
| 2022.01 | 103.8 | 100.5 | 54.0 | (60.3 projected, +4.5) | 8.92 |
| 2022.02 | 109.1 | 106.5 | 59.7 | (65.2 projected, +4.9) | 10.46 |
| 2022.03 | 117.0 | 115.8 | 78.5 | (70.7 projected, +5.5) | 10.20 |
| 2022.04 | 130.8 | 131.7 | 84.1 | (75.9 projected, +5.2) | 11.79 |
| 2022.05 | 137.6 (1) | 88.5 (2A) / 98.0 (2B) / 109.5 (2C) | (82.3 projected, +6.4) | (7.1) | |
| 2022.06 | (88.2 projected, +5.9) | ||||
| 2022.07 | (95.4 projected, +7.2) | ||||
| 2022.08 | (102.1 projected, +6.7) | ||||
| 2022.09 | (107.1 projected, +5.0) | ||||
| 2022.10 | (110.3 projected, +3.2) | ||||
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.
