The geomagnetic field was quiet to unsettled on May 18 under the weak influence of a high speed stream associated with CH1079. The high latitude magnetometer at Andenes recorded quiet to major storm levels.
Solar flux density measured at 20h UT on 2.8 GHz was 179.9 - increasing 15.5 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 97.67). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 5.9). Three hour interval K indices: 32111112 (planetary), 32122313 (Boulder), 62123114 (Andenes).
The background x-ray flux is at the class C2 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 11 active regions using 2K resolution (SN: 311) and in 11 active regions using 1K resolution (SN: 218) SDO/HMI images.
Region 13007 [S22W63] decayed slowly and
quietly.
Region 13010 [S16W05] gained a few spots as new flux emerged near the
center of the region causing polarity intermixing.
Region 13011 [N18W12] decayed slowly and was mostly quiet.
Region 13013 [S26W23] was quiet and stable.
Region 13014 [N22E18] developed further and has significant magnetic deltas within
both of the 2 main penumbrae. A major flare is possible.
Region 13015 [N14E13] was quiet and stable.
Region 13016 [S18E47] was quiet and stable.
Region 13017 [N12E41] was quiet and stable.
Region 13018 [S11E40] decayed slowly and quietly.
Spotted regions not observed (or interpreted
differently) by SWPC:
New region
S7577 [N17E36] emerged after noon with numerous small spots and
produced a single C flare.
New region S7578 [N11E82] rotated partly into view producing several
C flares. It is not yet
clear whether this is one or two spot groups.
Minor update added at 15:30
UT on May 19: A complex event began in AR S7577 at 06:32 UT and first
peaked as a C7.8 flare at 06:43. The flare then triggered an event which
spanned AR S7577 and 13017 and culminated in a major M5.6 flare at 07:19 UT.
A faint CME was observed, but it is uncertain if the major flare was the
source. AR 13014 was the source of an M1.5 flare at 10:09 and an M1.1 flare
at 15:16 UT.
What may have been a weak solar wind shock was observed at DSCOVR at 13:22
UT.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C2.8 | 02:01 | 13014 | GOES16 | ||
| C2.7 | 02:54 | 13011 | GOES16 | ||
| C2.9 | 04:46 | NE limb | S7578 | GOES16 | |
| C2.5 | 05:24 | 13014 | GOES16 | ||
| C2.3 | 05:54 | 13014 | GOES16 | ||
| C2.9 | 06:12 | 13014 | GOES16 | ||
| C3.6 | 06:19 | NE limb | S7578 | GOES16 | |
| C2.1 | 07:15 | 13014 | GOES16 | ||
| C2.7 | 08:02 | NE limb | S7578 | GOES16 | |
| C2.9 | 08:23 | NE limb | S7578 | GOES16 | |
| C2.6 | 09:42 | NE limb | S7578 | GOES16 | |
| C2.7 | 10:10 | 13014 | GOES16 | ||
| C2.6 | 10:42 | GOES16 | |||
| C2.0 | 12:18 | 13010 | GOES16 | ||
| C2.3 | 13:55 | N11E14 | 13015 | GOES16 | incorrectly attributed to AR 13011 by SWPC |
| C4.7 | 15:49 | N22E23 | 13014 | GOES16 | simultaneous flare in AR S7578 at the NE limb |
| C3.9 | 16:49 | 13014 | GOES16 | LDE | |
| C3.1 | 19:33 | S7577 | GOES16 | ||
| C4.8 | 21:19 | NE limb | S7578 | GOES16 | |
| C4.2 | 21:43 | 13014 | GOES16 | ||
| C5.1 | 21:49 | N22E21 | 13014 | GOES16 | |
| M1.1 | 22:02 | S15W01 | 13010 | GOES16 | |
| C3.8 | 23:41 | 13014 | GOES16 |
May 16, 18: No obviously Earth directed CMEs
were observed in available LASCO imagery.
May 17: The C6 flare in AR 13015 at 05:07 UT may have been the source
of a partial halo CME that was observed in LASCO imagery a little later. In
that case there is a chance of a weak CME impact on May 20.
[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 (CH1079) was Earth facing on May 15-18.
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 unsettled conditions are likely on May 19-21 due to effects from CH1079.
| 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 | ||||||||||
| 13007 | 2022.05.07 2022.05.08 |
10 | 15 | 9 | S22W61 | 0120 | CSO | CAO |
 |
 |
location: S22W63 |
| 13012 | 2022.05.09 2022.05.13 |
S19W67 | location: S17W69 | ||||||||
| 13008 | 2022.05.10 2022.05.11 |
N16W61 |
 |
location: N19W60 | |||||||
| 13013 | 2022.05.11 2022.05.14 |
3 | 2 | S27W25 | 0008 | AXX |
 |
 |
location: S26W23 | ||
| 13010 | 2022.05.11 2022.05.12 |
20 | 44 | 24 | S15W04 | 0070 | CSO | CAI |
 |
 |
location: S16W05 area: 0110 |
| 13011 | 2022.05.12 2022.05.13 |
1 | 1 | N18W06 | 0004 | AXX |
 |
 |
location: N18W12 |
||
| S7568 | 2022.05.13 | N15W38 |
 |
||||||||
| 13015 | 2022.05.13 2022.05.15 |
5 | 23 | 11 | N13E14 | 0100 | HSX | CSO |
 |
 |
|
| 13014 | 2022.05.13 2022.05.15 |
30 | 63 | 36 | N21E17 | 0850 | EKC | EKC |
 |
 |
beta-gamma-delta area: 1020 location: N22E18 |
| 13016 | 2022.05.15 2022.05.16 |
6 | 14 | 7 | S19E49 | 0180 | DAO | DAO |
 |
 |
location: S18E47 area: 0260 |
| S7573 | 2022.05.15 | N05W15 | likely SC24 group | ||||||||
| 13017 | 2022.05.15 2022.05.16 |
2 | 15 | 7 | N14E40 | 0020 | CRO | DRI |
 |
 |
location: N12E41 area: 0040 |
| 13018 | 2022.05.16 2022.05.17 |
4 | 6 | 3 | S11E41 | 0010 | AXX | BXO |
 |
 |
|
| S7576 | 2022.05.16 | N31W27 | |||||||||
| S7577 | 2022.05.18 | 15 | 7 | N17E36 | 0040 | DRI |
 |
||||
| S7578 | 2022.05.18 | 2 | 1 | N11E82 | 0015 | HRX |
 |
||||
| Total spot count: | 77 | 201 | 108 | ||||||||
| Sunspot number: | 147 | 311 | 218 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 110 | 240 | 147 | (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): | 162 | 171 | 174 | ||||||||
| 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 | 133.5 (1) | 54.3 (2A) / 93.4 (2B) / 107.8 (2C) | (82.3 projected, +6.4) | (6.0) | |
| 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.
