Solar Terrestrial Activity Report

Last major update issued on December 1, 2005 at 08:10 UTC. (Late update because of Internet connectivity problems)

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update November 9, 2005)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update November 9, 2005)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update November 9, 2005)]
[Historical solar and geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports (last update November 2, 2005)]

Recent activity

The geomagnetic field was quiet to active on November 30. Solar wind speed ranged between 515 and 755 (all day average 631) km/sec under the influence of a high speed stream from CH200.

Solar flux measured at 20h UTC on 2.8 GHz was 94.7. The planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.3)
Three hour interval K indices: 32243123 (planetary), 32243223 (Boulder).

The background x-ray flux is at the class B3 level.

At midnight there were 3 spotted regions on the visible solar disk. The solar flare activity level was moderate. A single M class event was recorded during the day.

Region 10824 was quiet and stable.
Region 10826 developed very quickly as new magnetic flux emerged in the center of the region. In this central area a magnetic delta structure has formed and further M class flares are likely. Flares: M1.4 at 17:52 UTC.
New region 10827 emerged in the northeast quadrant.

Coronal mass ejections (CMEs)

November 28 and 30: No obvious fully or partly Earth directed CMEs were observed.
November 29: A partial halo CME was observed over the southern hemisphere and the northwest limb after the C4 LDE in region 10824. The core ejected material was first observed over the southwest limb in LASCO C2 images at 17:30 and in C3 at 18:18 UTC while a more diffuse front appeared soon afterwards over the south pole, the southeast quadrant and some of the northwest quadrant.

Coronal holes

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

Recurrent trans equatorial coronal hole CH200 was in an Earth facing position on November 28-30.

Processed SOHO/EIT 284 image at 19:06 UTC on November 29. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be unsettled to minor storm on December 1-2 due to a high speed stream from CH200. The CME observed on November 29 could reach Earth embedded within the high speed stream and may be difficult to discern.

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) Material from a CME is likely to impact 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.

Propagation

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. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela). Propagation was best to Puerto Rico and Venezuela, however, most of the usual 50 kW stations from the New York and Boston areas were audible at fair levels.

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.

Monthly solar cycle data

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.