Solar Terrestrial Activity Report

Last major update issued on December 1, 2004 at 04:45 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update November 4, 2004)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update November 4, 2004)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update November 4, 2004)]
[Historical solar and geomagnetic data charts 1954-2004 (last update November 8, 2004)]
[Archived reports (last update November 20, 2004)]

Recent activity

The geomagnetic field was quiet to active on November 30. Solar wind speed ranged between 511 and 729 km/sec under the influence of a high speed stream from coronal hole CH129.

Solar flux measured at 20h UTC on 2.8 GHz was 110.6. The planetary A index was 15 (STAR Ap - based on the mean of three hour interval ap indices: 14.9).
Three hour interval K indices: 34323333 (planetary), 34323333 (Boulder).

The background x-ray flux is at the class B2 level.

At midnight there were 3 spotted regions on the visible solar disk. The solar flare activity level was low. A total of 2 C class events was recorded during the day.

Coronal mass ejections (CMEs)

November 28-30: No obviously Earth directed CMEs observed.

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

Large and well defined recurrent trans equatorial coronal hole CH129 was in a geoeffective position on November 26-28. A well defined coronal hole in the southeast quadrant is probably too far to the south to become geoeffective.

Processed SOHO/EIT 284 image at 07:06 UTC on November 30. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to quiet to unsettled on December 1-4.

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) 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 very poor. Propagation along long distance north-south paths is poor to fair. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: unidentified station from Brazil. On other frequencies stations from Brazil had the best signals. The only North American station noted was WWZN Boston on 1510 kHz.

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% less.

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.