Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 4, 2023 at 09:10 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 (June 1, 2023)
Solar cycle Solar cycles 23-25 (July 1, 2023) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (July 1, 2023) Noon SDO sunspot count 1K image / 4K (*)
  Solar cycles 1-24 (July 1, 2020) POES auroral activity level [October 2009 - December 2012]
  Comparison of cycles 21-25 (July 1, 2023) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (July 1, 2023) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (May 29, 2023) 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 very quiet on July 3. Solar wind speed at SOHO ranged between 339 and 432 km/sec. The high latitude magnetometer at Andenes recorded quiet to active levels.

Solar flux density measured at 20h UT on 2.8 GHz was 173.2 - increasing 1.4 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 146.10. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.0). Three hour interval K indices: 11111111 (planetary), 21112313 (Boulder), 31211343 (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 12 active regions using 2K resolution (SN: 327) and in 12 active regions using 1K resolution (SN: 223) SDO/HMI images.

Region 13354 [N16W71] was considerably less active than during the previous days and produced only a few C flares. The region lost spots and area.
Region 13355 [S10W16] was quiet and stable.
Region 13356 [S07W05] decayed slowly and quietly.
Region 13357 [S06E07] decayed as the trailing penumbra split into several penumbrae.
Region 13358 [S13E31] was unstable and produced many flares. Mature penumbra disappeared and small spots are distributed over a fairly large area.
Region 13359 [S21E27] has a couple of small magnetic delta configurations around the trailing penumbra. C and M class flaring is likely.
Region 13360 [N23E32] developed slowly and produced a few flares.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S8717 [S08E45] developed slowly and quietly.
S8720 [N30W25] reemerged with a tiny spot.
S8725 [S19E45] was quiet and stable.
S8728 [N23E59] developed slowly and quietly.
New region S8730 [N18E28] emerged with tiny spots.

A filament eruption in the southeast quadrant beginning near 02:30 UT on July 4 was associated with a partial halo CME. This CME could reach Earth on July 7.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C4.3 01:51   13354 GOES16  
C3.1 03:03   13354 GOES16 incorrectly attributed to smaller flare in AR 13358 by SWPC
C2.2 03:46   13354 GOES16  
C2.8 04:22   13354 GOES16  
C2.5 04:53   13358 GOES16 simultaneous flare in AR S8717
C2.4 05:11   13358 GOES16  
C2.5 05:31 S15E42 13358 GOES16  
C2.2 05:52   13359 GOES16  
C2.1 06:16   13354 GOES16  
C3.0 06:25   13359 GOES16 incorrectly attributed to AR 13358 by SWPC
C3.0 06:28   13360 GOES16  
C2.5 06:34   13354 GOES16  
M1.3/1N 06:53   13358 GOES16  
C5.9 07:04   13358 GOES16  
C3.2 07:49 S15E40 13358 GOES16  
C2.6 08:12   13358 GOES16  
C3.7 10:46   13358 GOES16  
C2.9 11:22   13358 GOES16  
C3.7 12:09 S23E35 13359 GOES16 simultaneous flare in AR 13354
C4.6 12:36 S20E34 13359 GOES16 simultaneous flare in AR 13354. Incorrectly attributed to AR 13358 by SWPC
C3.0 14:09   13358 GOES16  
C3.5 14:48   13358 GOES16 incorrectly attributed to AR 13360 by SWPC
C4.4 15:14   13358 GOES16  
C5.0 15:21   13358 GOES16 incorrectly attributed to AR 13360 by SWPC
C2.6 17:26   13358 GOES16  
C3.3 18:04   13360 GOES16  
C5.0 18:20   13358 GOES16 incorrectly attributed to AR 13360 by SWPC
C2.6 18:39   13358 GOES16  
C2.9 18:57   13354 GOES16  
C2.5 19:34   13354 GOES16  
C2.1 20:19   13359 GOES16  
C3.9 20:55   13359 GOES16 incorrectly attributed to AR 13360 by SWPC
C8.9/1F 21:12 N22E33 13360 GOES16 moderate type II radio sweep
C4.4 21:31   13360 GOES16  
C2.9 23:11   13360 GOES16  
C4.3 23:53 N15W73 13354 GOES16  

Coronal mass ejections (CMEs)

July 1-3: No obviously Earth directed CMEs were observed.

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 small southern hemisphere coronal hole (CH1157) was Earth facing on June 30. A recurrent northern hemisphere coronal hole (CH1158) will likely be Earth facing on July 4-5.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle and high latitudes is fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

Quiet to unsettled geomagnetic conditions are possible on July 4 due to weak effects from CH1157. Quiet conditions are likely on July 5-6. On July 7 effects from the July 4 CME could cause unsettled to minor storm conditions. A high speed stream associated with CH1158 could cause unsettled to minor storm conditions on July 7-8.

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
13348 2023.06.21
2023.06.23
      S33W89           location: S34W77
13351 2023.06.22
2023.06.23
      N21W78           location: N22W730
13354 2023.06.22
2023.06.26
25 37 20 N16W72 1130 FKC FKC beta-gamma

area: 0800

13355 2023.06.26
2023.06.27
  11 4 S16W18 0025   BXO

location: S10W16

S8707 2023.06.27       N20W47            
13356 2023.06.29
2023.06.30
2 6 3 S07W06 0010 BXO BXO location: S07W05
S8711 2023.06.29       N14W03            
S8712 2023.06.29       S12W30            
S8713 2023.06.29       S12W41            
13357 2023.06.30
2023.07.01
6 31 19 S07E05 0050 DAO DAI location: S06E07

area: 0180

13358 2023.06.30
2023.07.01
14 49 27 S13E29 0100 DAI DRI beta-gamma

location: S13E31

area: 0220

13359 2023.06.30
2023.07.01
8 19 7 S22E26 0080 DSO DSI beta-gamma-delta

location: S21E27

area: 0270

S8717 2023.06.30   11 3 S08E45 0020   BXO  
S8718 2023.06.30       N14W04            
13360 2023.06.30
2023.07.01
2 20 11 N23E30 0030 HSX CAO beta-gamma

location: N23E32

area: 0090

S8720 2023.06.30   1 1 N30W25 0003   AXX    
S8721 2023.06.30
2023.07.01
      N17E12            
S8722 2023.07.01       S17W42            
S8724 2023.07.02       N09E25          
S8725 2023.07.02   8 2 S19E45 0010   BXO  
S8726 2023.07.02       S37E25          
S8727 2023.07.02       N29W46          
S8728 2023.07.02   9 3 N23E59 0020   CRO  
S8729 2023.07.02       N40W33          
S8730 2023.07.03   5 3 N18E28 0012   AXX    
Total spot count: 57 207 103  
Sunspot number: 117 327 223  (total spot count + 10 * number of spotted regions)
Weighted SN: 87 238 134  (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): 129 180 178  

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 (SC24 solar max) 7.88
2017.09 91.3 92.3 43.6 18.2 (-1.3) 18.22
(SC24 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
2021.12 103.0 99.8 67.5 55.9 (+5.1) 6.40
2022.01 103.8 100.5 55.3 60.1 (+4.2) 8.92
2022.02 109.1 106.5 60.9 64.7 (+4.6) 10.46
2022.03 117.0 115.8 78.6 68.7 (+4.0) 10.20
2022.04 130.8 131.7 84.0 73.0 (+4.3) 11.79
2022.05 133.8 136.8 96.5 77.4 (+4.4) 7.48
2022.06 116.1 119.8 70.3 81.1 (+3.7) 8.20
2022.07 125.4 129.5 91.4 86.7 (+5.6) 9.51
2022.08 114.2 117.1 74.6 92.5 (+5.8) 10.92
2022.09 135.1 136.5 96.0 96.4 (+3.9) 12.18
2022.10 133.5 132.7 95.5 98.7 (+2.3) 11.16
2022.11 123.4 120.7 80.5 101.0 (+2.3) 9.33
2022.12 147.9 143.4 112.8 106.6 (+5.6) 10.99
2023.01 182.4 176.6 143.6 (113.7 projected, +6.1) 8.73
2023.02 167.2 163.2 110.9 (118.5 projected, +4.8) 14.48
(current
SC25 peak)
2023.03 157.2 155.6 122.6 (121.6 projected, +3.1) 14.42
2023.04 145.4 146.4 96.4 (127.0 projected, +5.4) 13.40
2023.05 155.6 159.2 137.9 (132.7 projected, +5.7) 10.67
2023.06 161.7 166.8 163.4 (135.9 projected, +3.2) 8.9
2023.07  169.6 (1)   11.7 (2A) / 120.7 (2B) / 174.9 (2C) (135.4 projected, -0.5) (4.2)
2023.08       (136.4 projected, +1.0)  
2023.09       (139.8 projected, +3.4)  
2023.10       (141.6 projected, +1.8)  
2023.11       (144.2 projected max SC25, +2.6)  
2023.12       (143.4 projected, -0.1)  
2024.01       (140.1 projected, -3.3)  

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: WDC-SILSO, Royal Observatory Of Belgium, Brussels

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.