Solar Terrestrial Activity Report

Last major update issued on November 28, 2004 at 05:05 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 unsettled on November 27. Solar wind speed ranged between 366 and 438 km/sec.

Solar flux measured at 20h UTC on 2.8 GHz was 110.3. The planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.0).
Three hour interval K indices: 12323332 (planetary), 22323322 (Boulder).

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

At midnight there were 4 spotted regions on the visible solar disk. The solar flare activity level was low. A total of 2 C class events were recorded during the day.

Region 10704 decayed quickly and had only two small spots left at midnight.
Region 10706 decayed slowly and was mostly quiet. A filament eruption was observed in this region early on November 28, however, no CME has been observed yet. Flare: C1.6 at 05:16 UTC.
Region 10707 decayed and lost all spots in the southern part. Minor development was observed near the eastern edge of the major penumbra. Flare: C2.0 at 02:04 UTC.
Region 10708 was quiet and stable. The region has a positive polarity area embedded inside a weak negative polarity area. Other than this the region currently does not look as if it is capable of producing interesting events..

Coronal mass ejections (CMEs)

November 25-27: 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. This coronal hole has developed quickly over the last rotation. 

Processed SOHO/EIT 284 image at 01:06 UTC on November 28. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to unsettled on November 28 and most of November 29. During the latter half of November 29 a strong high speed stream from coronal hole CH129 is expected to arrive. This will cause unsettled to major storm conditions until December 1.

Coronal holes (1) Coronal mass ejections (2) M and X class flares (3)
Coronal hole indicator CME indicator M and X class flare indicator

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 to useless. Propagation along long distance north-south paths is very poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: only faint audio noted for a few minutes, otherwise nothing. On other frequencies propagation was generally extremely poor with audio only noted from Rádio Sociedade on 740 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.

Active region Date numbered SEC
spot
count
STAR
spot
count
Location at midnight Area Classification Comment
10703 2004.11.18     N13W70     plage
10704 2004.11.18 3 2 N13W44 0030 HAX classification was AXX
at midnight, area 0010
10706 2004.11.24 6 2 S07E31 0120 CAO classification was CSO
at midnight. area 0090
10707 2004.11.24 14 11 S16E27 0170 DAI classification was DAO
at midnight, area 0120
10708 2004.11.26 1 1 N10E67 0100 HSX  
S483 visible on
2004.11.24
    S09W39     plage
Total spot count: 24 17
SSN: 64 57

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)
2003.08 122.1 72.7 60.0 (-1.7)
2003.09 112.2 48.7 59.5 (-0.5)
2003.10 151.7 65.5 58.2 (-1.3)
2003.11 140.8 67.3 56.7 (-1.5)
2003.12 114.9 46.5 54.8 (-1.9)
2004.01 114.1 37.3 52.0 (-2.8)
2004.02 107.0 45.8 49.3 (-2.7)
2004.03 112.0 49.1 47.1 (-2.2)
2004.04 101.2 39.3 45.5 (-1.6)
2004.05 99.8 41.5 (42.8 predicted, -2.7)
2004.06 97.4 43.2 (40.0 predicted, -2.8)
2004.07 119.1 51.0 (38.2 predicted, -1.8)
2004.08 109.6 40.9 (36.6 predicted, -1.6)
2004.09 103.1 27.7 (34.7 predicted, -1.9)
2004.10 105.9 48.4 (32.5 predicted, -2.2)
2004.11 113.4 (1) 65.6 (2) (31.0 predicted, -1.5)

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.


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