Solar Terrestrial Activity Report

Last major update issued on November 28, 2007 at 05:25 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-23 (last update October 4, 2007)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update October 4, 2007)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update October 4, 2007)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports (last update October 3, 2007)]

Recent activity

The geomagnetic field was quiet on November 27. Solar wind speed ranged between 445 and 539 km/s (average speed was 468 km/s, decreasing 106 km/s from the previous day).

Solar flux measured at 20h UTC on 2.8 GHz was 71.4. The planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.5). Three hour interval K indices: 12111012 (planetary), 12231101 (Boulder).

The background x-ray flux is below the class A1 level.

At midnight the visible solar disk was spotless. The solar flare activity level was very low. No C class events were recorded during the day.

Coronal mass ejections (CMEs)

November 25-27: No obvious fully or partly Earth directed CMEs were observed in LASCO imagery.

Coronal holes

Coronal hole history (since late October 2002)
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago

A small trans equatorial coronal hole (CH301) was in an Earth facing position on November 24-25.

Processed SOHO/EIT 195 image at 10:13 UTC on November 27. The darkest areas on the solar disk are likely coronal holes.

Propagation

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

Monitoring remarks from a location near N58E06: November 12: During the evening fairly strong signals from east coast USA stations. 1470 WJDY, 1500 WFIF and 1520 WIZZ were all good on their daytime power. The best Trans Atlantic propagation sector was 270-310 degrees.

Forecast

The geomagnetic field is expected to be mostly quiet on November 28 with a chance of isolated unsettled or active intervals due to coronal hole effects. Quiet conditions are likely on November 29 - December 4.

Coronal holes (1) Coronal mass ejections (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: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% probability.

Active solar regions (Recent map)

Compare to the previous day's image.

Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SEC. 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 SEC or where SEC has observed no spots. SEC active region numbers in the table below and in the active region map above are the historic SEC/USAF numbers.

Active region Date numbered SEC
spot
count
STAR
spot
count
Location at midnight Area Classification Comment
10975 2007.11.24     N03W51     plage
Total spot count: 0 0  
SSN: 0 0  

Monthly solar cycle data

Month Average solar
flux at Earth
International sunspot number Smoothed sunspot number
2000.04 184.2 125.5 120.8
cycle 23 sunspot max.
2000.07 202.3 170.1 119.8
2001.12 235.1 132.2 114.6 (-0.9)
2006.09 77.8 14.4 15.6 (+0.0)
2006.10 74.3 10.4 14.2 (-1.4)
2006.11 86.3 21.5 12.7 (-1.5)
2006.12 84.5 13.6 12.1 (-0.6)
2007.01 83.3 16.9 12.0 (-0.1)
2007.02 77.7 10.6 11.6 (-0.4)
2007.03 72.2 4.8 10.8 (-0.8)
2007.04 72.4 3.7 9.9 (-0.9)
2007.05 74.4 11.7 (8.7 predicted, -1.2)
2007.06 73.7 12.0 (7.5 predicted, -1.2)
2007.07 71.6 10.0 (6.7 predicted, -0.8)
2007.08 69.1 6.2 (6.2 predicted, -0.5)
2007.09 67.1 2.4 (6.2 predicted, +0.0)
2007.10 67.4 0.9 (6.7 predicted, +0.5)
2007.11 69.4 (1) 2.5 (2) (7.3 predicted, +0.6)

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
2) Unofficial, accumulated value based on the Boulder (NOAA/SEC) sunspot number. The official international sunspot number is typically 30-50% lower.

This report has been prepared by Jan Alvestad. It is based partly on my own observations and analysis, and partly on data from some of these solar data sources. All time references are to the UTC day. Comments and suggestions are always welcome.


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