Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 6, 2019 at 03:10 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 (August 4, 2019)
Solar cycle Solar cycles 23-24 (August 1, 2019) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24 progress (August 1, 2019) / Cycle 25 spots (July 10, 2019) Noon SDO sunspot count 1K image / 4K (*)
  Solar cycles 1-24 (July 17, 2015) POES auroral activity level October 2009 - December 2012]
  Comparison of cycles 21, 22, 23 and 24 (August 1, 2019) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12, 13, 14, 16 and 24 (August 1, 2019) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (July 27, 2019)  

Recent activity

The geomagnetic field was quiet to minor storm on August 5 under the influence of a high speed stream from CH932. Solar wind speed at SOHO ranged between 458 and 708 km/sec.

Solar flux at 20h UTC on 2.8 GHz was 68.1 (increasing 0.6 over the previous solar rotation). The average 90 day 10.7 flux at 1 AU was 70.5 (The centered average 90 day SF at 1 AU reached a low of 67.77 on December 9, 2018. The centered 1 year average SF at 1 AU reached a minimum of 69.83 on February 3, 2019. The current 1 year average 1 AU SF is 69.83). The Potsdam WDC planetary A index was 33 (STAR Ap - based on the mean of three hour interval ap indices: 33.4). Three hour interval K indices: 13555543 (planetary), 24545533 (Boulder)

The background x-ray flux is at the class A7 level.

At the time of counting spots (see image time), spots were observed in 1 active region using 2K resolution (SN: 12) and in 1 active region using 1K resolution (SN: 11) SDO/HMI images.

New region 12745 [S06E09] emerged on August 4, then decayed. New flux emerged after 06h UT on August 5 and the region was numbered by SWPC. By the end of the day the region had again decayed significantly.

C2+ flares:

Magnitude Peak time (UT) Location AR Recorded by Comment
           

Coronal mass ejections (CMEs)

August 3-5: 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 well defined recurrent trans equatorial coronal hole (CH932) was Earth facing on August 1-2.

Propagation

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

Forecast

The geomagnetic field is expected to be quiet toactive on August 6 due to effects from CH932 and quiet to unsettled on August 7 becoming quiet on August 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 numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC. 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.

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 Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
12745 2019.08.04
2019.08.05
2 2 1 S05E08 0010 BXO AXX  
S6230 2019.08.06       S29W18 @ 09:00 0002   AXX   cycle 25
S6231 2019.08.06       N33W00 @ 12:00 0002   AXX   cycle 25
S6232 2019.08.06       N05E18 @ 12:00 0005   BXO    
Total spot count: 2 2 1  
Sunspot number: 12 12 11  (total spot count + 10 * number of spotted regions)
Weighted SN: 2 2 1  (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): 13 7 9 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)
2018.03 68.3 67.6 2.5 9.9 (-2.7) 7.91
2018.04 70.0 70.5 8.9 7.9 (-2.0) 6.80
2018.05 70.8 72.4 13.2 7.5 (-0.4) 7.16
2018.06 72.5 74.7 15.9 7.3 (-0.2) 6.83
2018.07 69.6 72.3 1.6 7.1 (-0.2) 5.38
2018.08 69.1 70.8 8.8 6.8 (-0.3) 8.98
2018.09 68.2 69.0 3.3 6.6 (-0.2) 8.91
2018.10 69.6 69.1 4.9 6.9 (+0.3) 6.49
2018.11 68.9 67.4 4.9 6.7 (-0.2) 5.78
2018.12 70.0 67.8 3.1 6.0 (-0.7) 6.10
2019.01 71.5 69.2 7.8 5.4 (-0.6) 5.89
2019.02 70.6 68.9 0.8 (5.2 projected, -0.2)
solar minimum candidate
6.88
2019.03 71.6 70.8 9.5 (5.2 projected, 0.0) 6.12
2019.04 72.4 72.9 9.1 (5.5 projected, +0.3) 6.06
2019.05 71.3 72.8 10.1 (5.9 projected, +0.4) 6.98
2019.06 68.1 70.3 1.2 (6.6 projected, +0.7) 4.26
2019.07 67.1 69.3 0.9 (7.4 projected, +0.8) 5.4
2019.08 (66.9)   0.4 (2A) / 2.4 (2B) / 2.2 (2C) (8.3 projected, +0.9) (9.7)
2019.09       (9.1 projected, +0.8)  
2019.10       (9.4 projected, +0.3)  
2019.11       (10.3 projected, +0.9)  
2019.12       (11.8 projected, +1.5)  
2020.01       (13.5 projected, +1.7)  

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.

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.