Solar Terrestrial Activity Report

Last major update issued on November 25, 2006 at 06:00 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update November 12, 2006)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update November 12, 2006)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update November 12, 2006)]
[Historical solar and geomagnetic data charts 1954-2005 (last update March 3, 2006)]
[Archived reports (last update November 12, 2006)]

Recent activity

The geomagnetic field was quiet to minor storm on November 24. Solar wind speed ranged between 472 and 618 km/s (all day average 560 km/s - increasing 138 km/s over the previous day) under the influence of a high speed stream from CH248.

Solar flux measured at 20h UTC on 2.8 GHz was 77.4. The planetary A index was 21 (STAR Ap - based on the mean of three hour interval ap indices: 20.8). Three hour interval K indices: 35533222 (planetary), 34533222 (Boulder).

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

At midnight there was 1 spotted region on the visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.

Spotted regions not numbered by NOAA/SEC:
[S684] A new region began to rotate into view at the southeast limb late on November 24. Location at midnight: S10E85. This region may be capable of C class flaring.

Coronal mass ejections (CMEs)

November 22-24: No obvious partly or fully Earth directed CMEs were detected 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 recurrent coronal hole, CH248, in the southern hemisphere was in an Earth facing position on November 19-23. Only the northernmost extensions, including a trans equatorial extension in the easternmost part of the coronal hole, were within potentially geoeffective positions.

Processed SOHO/EIT 284 image at 19:06 UTC on November 24. The darkest areas on the solar disk are likely coronal holes.


The geomagnetic field is expected to be quiet to active on November 25-26 due to effects from CH248, occasional minor storm intervals are possible. Mostly quiet conditions are likely on November 27-30.

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.


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

Monitoring remarks from a location near N58E06: At 03h UTC there were quite a few stations around. Signals from Newfoundland and Cuba were the strongest, with some stations form Venezuela and Colombia reaching fair to good signal levels. Another burst of geomagnetic activity had wiped out most of the stations by 04h UTC.

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
Location at midnight Area Classification Comment
S683 2006.11.23     S02E26     plage
S684 2006.11.24   1 S10E85 0120 HAX  
Total spot count: 0 1  
SSN: 0 11  

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)
2005.08 90.5 36.4 27.4 (-1.7)
2005.09 91.1 21.9 25.8 (-1.6)
2005.10 77.0 8.7 25.5 (-0.3)
2005.11 86.3 18.0 24.9 (-0.6)
2005.12 90.7 41.1 23.0 (-1.9)
2006.01 83.4 15.3 20.8 (-2.2)
2006.02 76.5 4.9 18.6 (-2.2)
2006.03 75.4 10.6 17.3 (-1.3)
2006.04 89.0 30.2 17.1 (-0.2)
2006.05 80.9 22.2 (16.8 predicted, -0.3)
2006.06 76.5 13.9 (15.1 predicted, -1.7)
2006.07 75.7 12.2 (13.2 predicted, -1.9)
2006.08 79.0 12.9 (12.7 predicted, -0.5)
2006.09 77.8 14.5 (12.6 predicted, -0.1)
2006.10 74.3 10.4 (11.5 predicted, -1.1)
2006.11 87.3 (1) 25.5 (2) (10.1 predicted, -1.4)

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.

[DX-Listeners' Club]