Solar Terrestrial Activity Report

Activity chart

Last major update issued on May 19, 2022 at 04:00 UT. Minor update added at 15:30 UT.

Charts (* = updated daily) Data and archive
  Solar wind (*) Solar and geomagnetic data - last month (*)
  Electron fluence (*) Archived daily reports and monthly data since 2003.01 (May 1, 2022)
Solar cycle Solar cycles 23-25 (May 1, 2022) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (May 1, 2022) Noon SDO sunspot count 1K image / 4K (*)
  Solar cycles 1-24 (June 1, 2020) POES auroral activity level October 2009 - December 2012]
  Comparison of cycles 21-25 (May 1, 2022) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (May 1, 2022) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (April 10, 2022) Cycle 25 spots (final update December 25, 2019)
  Solar cycles 24-25 transition using 365d smoothing Research: Solar Cycle 25 Started on November 17, 2019 with 365 Days Smoothing

Recent activity

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 [S22W49] 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  

Coronal mass ejections (CMEs)

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 holes

[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.

Propagation

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.

Forecast

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.

Active solar regions


(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  

Monthly solar cycle data

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.

Solar cycles 24-25

Smoothed SF and sunspot numbers

 

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.