Solar Terrestrial Activity Report

Activity chart

Last major update issued on November 29, 2020 at 06:55 UT. Minor updates posted at 13:35 and 16:40 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 quiet to unsettled on November 28 under the influence of coronal hole effects. The high latitude magnetometer at Andenes recorded quiet to active conditions.

Solar flux at 20h UT on 2.8 GHz was 109.6 - increasing 32.3 over the previous solar rotation. (Centered 1 year average SF at 1 AU: Minimum of 69.13 on November 17, 2019. Current: 72.12). The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 9.6). Three hour interval K indices: 33322121 (planetary), 23323211 (Boulder), 43212133 (Andenes).

The background x-ray flux is at the class B5 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 6 active regions using 2K resolution (SN: 151) and in 6 active regions using 1K resolution (SN: 97) SDO/HMI images.

Region 12783 [S22W75] decayed slowly and quietly.
Region 12785 [S23W04] developed slowly in the trailing spot section.
Region 12786 [S17E10] gained small spots and produced a few small C flares. A major flare is possible.
Region 12787 [N29E50] was quiet and stable.

Spotted regions not observed (or interpreted differently) by SWPC:
New region S6636 [S12E02] emerged early in the day with a few spots and decayed slowly after noon.
New region S6638 [S26E57] developed a few spots in a plage area that rotated into view on November 26.

Minor update added at 13:35 UT on November 29:

An active region just behind the southeast limb was the source of a long duration M4.4 event peaking at 13:11 UT. The flare was very impressive in SDO/AIA imagery and may have been associated with a very wide CME. This could be the same region that produced a backsided full halo CME a few days ago. LASCO imagery is not yet available for analysis of the current CME.

Minor update added at 16:40 UT on November 29:

The core of the fast CME associated with the M4 LDE was almost 150 degrees wide. Faint traces of the CME were observed over the poles and even the western limbs making this a full halo CME. It is not yet certain if there will be a faint impact from this CME. If it happens, December 1-2 are the most likely dates.

The shockwave from the flare was observed affecting the corona above most of the visible eastern hemisphere.

C2+ flares:

Magnitude Peak time (UT) Location AR Recorded by Comment
C2.9 13:35 S15E22 12786 GOES16  
C3.1 23:18 S18E13 12786 GOES16  

Coronal mass ejections (CMEs)

November 26-28: 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]

No obvious coronal holes are currently in or near Earth facing positions.

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 fair.

Forecast

The geomagnetic field is expected to be quiet on November 29 - December 2.

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
1 2 1 S22W75 0050 HSX CSO area: 0090
12784 2020.11.20
2020.11.21
      N32W69           location: N31W63
12785 2020.11.22
2020.11.22
8 27 12 S25W01 0120 FSO FSI area: 0260
12786 2020.11.22
2020.11.23
17 54 21 S18E15 0780 FKO FKI beta-gamma

area: 1040

location: S16E10

S6626 2020.11.23       N27W37            
S6629 2020.11.24       S19W21            
S6631 2020.11.24       N28W34            
S6632 2020.11.26       S05W07            
12787 2020.11.26
2020.11.27
1 3 1 N29E51 0010 AXX HRX  
S6634 2020.11.27       S03E13          
S6635 2020.11.27       S19W30          
S6636 2020.11.28   2 1 S12E02 0006   BXO  
S6637 2020.11.28       S32W17          
S6638 2020.11.28   3 1 S26E57 0015   CRO    
Total spot count: 27 91 37  
Sunspot number: 67 151 97  (total spot count + 10 * number of spotted regions)
Weighted SN: 47 117 63  (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): 74 83 78 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 (88.3) (1)   24.1 (2A) / 25.9 (2B) / 30.5 (2C) (13.1 projected, +1.4) (5.0)
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.