Solar Terrestrial Activity Report

Activity chart

Last major update issued on November 25, 2020 at 07:05 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 (November 3, 2020)
Solar cycle Solar cycles 23-25 (November 1, 2020) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (November 1, 2020) 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 (November 1, 2020) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (November 1, 2020) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (July 6, 2020) Cycle 25 spots (final update December 25, 2019)
  Solar cycles 24-25 using 365d smoothing (*) Recent research
    Current research: Solar Cycle 25 Started on November 17, 2019 with 365 Days Smoothing

Recent activity

The geomagnetic field was very quiet on November 24. The high latitude magnetometer at Andenes recorded quiet to unsettled conditions.

Solar flux at 20h UT on 2.8 GHz was 100.4 - increasing 12.8 over the previous solar rotation. (Centered 1 year average SF at 1 AU: Minimum of 69.13 on November 17, 2019. Current: 71.74). The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.0). Three hour interval K indices: 11001101 (planetary), 11121211 (Boulder), 12001003 (Andenes).

The background x-ray flux is at the class B4 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 7 active regions using 2K resolution (SN: 102) and in 5 active regions using 1K resolution (SN: 64) SDO/HMI images.

Region 12783 [S21W20] decayed slowly and quietly.
Region 12785 [S21E46] was mostly quiet and stable.
Region 12786 [S16E61] rotated fully into view revealing trailing spots with a nearly 20 degrees longitudinal separation from the huge asymmetric leader spot. A major flare is possible. The region was mostly quiet producing only a long during C1.1 even peaking at 06:06 UT (After careful analysis of SDO/AIA imagery it became clear that SWPC wrongly attributed this event to AR 12785 and erroneously split the LDE into two C1 events). A more significant C3.4 flare was recorded at 04:02 UT on November 25.

Spotted regions not observed (or interpreted differently) by SWPC:
S6618 [S22W40] reemerged with tiny spots.
New region S6629 [S19E31] emerged with tiny spots.
New region S6630 [S21W65] emerged with tiny spots.
New region S6631 [N28E18] emerged with a tiny spot.

A full halo CME became visible in LASCO C2 imagery after 12:48 UT. While its origin was in the southern hemisphere, there was no associated frontside activity to explain this event. This is believed to be a backside event.

C2+ flares:

Magnitude Peak time (UT) Location AR Recorded by Comment
           

Coronal mass ejections (CMEs)

November 22-24: No obviously Earth directed CMEs were observed in available LASCO imagery.

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 recurrent northern hemisphere coronal hole (CH980) was Earth facing on November 18-22.

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

The geomagnetic field is expected to be quiet to unsettled on November 25-26 due to effects from CH980 and quiet on November 27-28.

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 red colored.

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
12783 2020.11.16
2020.11.17
4 15 7 S20W19 0100 CSO CSO  
S6616 2020.11.17       N19W41            
S6618 2020.11.17   2   S22W40 0002   AXX    
S6621 2020.11.19       S18W15            
12784 2020.11.20
2020.11.21
      N32W13          
12785 2020.11.22
2020.11.22
1 2 1 S20E44 0140 HSX HSX area: 0170

location: S21E46

S6624 2020.11.22       N08W57            
12786 2020.11.22
2020.11.23
2 8 4 S15E59 0380 CKO FKO area: 0840

location: S16E61

S6626 2020.11.23       N27E15          
S6627 2020.11.23       N07W13          
S6628 2020.11.23       S34W32          
S6629 2020.11.24   2 1 S19E31 0003   AXX    
S6630 2020.11.24   2 1 S21W65 0005   BXO    
S6631 2020.11.24   1   N28E18 1   AXX    
Total spot count: 7 32 14  
Sunspot number: 37 102 64  (total spot count + 10 * number of spotted regions)
Weighted SN: 27 52 34  (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): 41 56 51 k * (sunspot number)
As of May 7, 2016: k = 1.1 for SWPC, k = 0.55 for MSN 2K, k = 0.80 for MSN 1K (MSN=Magnetic Sunspot Number)

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 (cycle 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)
2019.05 71.3 72.8 9.9 3.9 (-0.4) 6.98
2019.06 68.1 70.3 1.2 3.7 (-0.2) 4.26
2019.07 67.1 69.3 0.9 3.5 (-0.2) 5.36
2019.08 67.0 68.7 0.5 3.4 (-0.1) 6.79
2019.09 67.9 68.7 1.1 3.1 (-0.3) 9.81
2019.10 67.4 67.0 0.4 2.6 (-0.5) 7.53
2019.11 70.2 68.7 0.5 2.0 (-0.6)
(November 17, 2019 is
the solar minimum using 365d
smoothing for 1 AU solar flux,
NOAA SN and both
of STAR 1K and 2K SN)
4.19
2019.12 70.8 68.6 1.6 1.8 (-0.2)
(ISN 13 months smoothed
solar minimum)
3.22
2020.01 72.2 69.9 6.4 2.2 (+0.4) 4.39
2020.02 71.0 69.3 0.4 2.8 (+0.6) 6.16
2020.03 70.2 69.5 1.5 3.0 (+0.2) 5.63
2020.04 69.5 70.0 5.4 3.6 (+0.6) 5.32
2020.05 69.0 70.6 0.2 (4.7 projected, +1.1) 3.80
2020.06 69.5 71.7 5.8 (5.9 projected, +1.2) 3.75
2020.07 69.5 71.8 6.3 (6.9 projected, +1.0) 4.28
2020.08 71.6 73.4 7.6 (8.2 projected, +1.3) 5.68
2020.09 70.7 71.4 0.7 (10.2 projected, +2.0) 8.59
2020.10 74.6 74.2 14.4 (11.7 projected, +1.5) 6.13
2020.11 (85.2) (1)   17.1 (2A) / 21.4 (2B) / 27.2 (2C) (13.1 projected, +1.4) (4.6)
2020.12       (15.2 projected, +2.1)  
2021.01       (17.2 projected, +2.0)  
2021.02       (19.2 projected, +2.0)  
2021.03       (21.4 projected, +2.2)  
2021.04       (23.5 projected, +2.1)  

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
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 transition

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.