Solar Terrestrial Activity Report

Last major update issued on November 24, 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 on November 23. Solar wind speed ranged between 366 and 471 km/sec.

Solar flux measured at 20h UTC on 2.8 GHz was 106.9. The planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 5.0).
Three hour interval K indices: 21111212 (planetary), 21111212 (Boulder).

The background x-ray flux is at the class B3 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 was recorded during the day.

Region 10704 decayed slowly and lost penumbra except on the main penumbra.
"New" region 10705 was first observed with spots on November 14, then quickly lost its spots. A single spot was visible again on Nov. 21 and the region developed slowly on Nov. 22-23. At this time SEC noticed the presence of the region.

Spotted regions not numbered by NOAA/SEC:
[S481] This region, probably old region 10693, rotated partly into view at the southeast limb on November 23. Location at midnight: S15E80.
[S482] A new region rotated partly into view at the southeast limb late on November 23. M flares are possible. Location at midnight: S06E82. Flares: C2.3 at 08:52 and C6.5 at 15:07 UTC.

Coronal mass ejections (CMEs)

November 21-23: 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. Recurrent trans equatorial coronal hole CH129 will likely rotate into a geoeffective position on November 27.

Processed SOHO/EIT 284 image at 13:06 UTC on November 23. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to unsettled on November 24. A high speed stream from coronal hole CH128 will likely arrive on November 25 and cause unsettled to active conditions that day becoming quiet to active on November 26-27.

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. 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: Radio Cristal del Uruguay with an occasionally good signal. On 930 kHz Radio Monte Carlo (Uruguay) was the best station. On other frequencies mainly stations from the southeastern part of Brazil were observed. Only 2 North American stations could be heard: 1030 WBZ and 1510 WWZN.

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
10701 2004.11.11 1   S15W83 0030 HSX rotated out of view
10703 2004.11.18     N12W18     plage
10704 2004.11.18 6 6 N12E11 0090 DSO classification was CAO
at midnight
10705 2004.11.23 8 3 S04W64 0070 DAO formerly region S477
classification was CSO
at midnight, area 0050
S480 visible on
2004.11.19
    S12E18     plage
S481 visible on
2004.11.23
  1 S15E80 0100 HAX  
S482 visible on
2004.11.23
  1 S06E82 0060 HSX  
Total spot count: 15 11
SSN: 45 51

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)
2004.11 114.1 (1) 57.0 (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]