Solar Terrestrial Activity Report

Last major update issued on November 26, 2004 at 04:40 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 minor storm on November 25. Solar wind speed ranged between 455 and 556 km/sec under the influence of a high speed stream from coronal hole CH128.

Solar flux measured at 20h UTC on 2.8 GHz was 109.4. The planetary A index was 20 (STAR Ap - based on the mean of three hour interval ap indices: 20.1).
Three hour interval K indices: 45344322 (planetary), 44333423 (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 1 C class event was recorded during the day. That flare was a C2.6 event at 11:01 with an origin behind the northeast limb.

Region 10704 decayed slowly and quietly.
Region 10706 developed slowly as a few spots emerged in the south and southwest.
Region 10707 became less complex as the positive polarity spot in the north separated from the negative polarity spots in the main penumbra.

Coronal mass ejections (CMEs)

November 23-25: 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

Recurrent coronal hole CH128 in the southern hemisphere was in a geoeffective position on November 21-23. Large and well defined recurrent trans equatorial coronal hole CH129 will rotate into a geoeffective position on November 27-28.

Processed SOHO/EIT 284 image at 01:06 UTC on November 26. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to quiet to active on November 26 and quiet to unsettled on November 27-29. Unsettled to major storm is possible on November 30 when the high speed stream from coronal hole CH129 arrives.

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 poor to very poor. Propagation along long distance north-south paths is poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: no stations heard. On other frequencies the best signals were from Brazil: 740 (Rádio Sociedade), 930 (Rádio Metropolitana), 980 (Rádio Nacional) and 1440 (Rádio Jovem Pan). Three stations from North America were observed: Greenland on 650 kHz with a good signal, 930 - unidentified and 1510 kHz WWZN Boston.

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     N13W44     plage
10704 2004.11.18 6 3 N13W17 0070 DAO classification was CAO
at midnight, area 0060
10705 2004.11.23 3   S04W95 0060 CAO rotated out of view
10706 2004.11.24 6 6 S08E56 0070 DAO location: S07E56
area was 0090
at midnight
10707 2004.11.24 6 5 S15E57 0110 CAO location: S15E53
classification was DAO
at midnight, area 0080
S483 visible on
2004.11.24
    S09W13     plage
Total spot count: 21 14
SSN: 61 44

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)
2004.11 113.6 (1) 61.4 (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.


[DX-Listeners' Club]