Solar Terrestrial Activity Report

Last major update issued on November 18, 2007 at 06:05 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-23 (last update October 4, 2007)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update October 4, 2007)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update October 4, 2007)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports (last update October 3, 2007)]

Recent activity

The geomagnetic field was quiet to unsettled on November 17. Solar wind speed ranged between 366 and 513 km/s (average speed was 438 km/s, decreasing 90 km/s from the previous day) under the diminishing influence of a high speed stream from CH298.

Solar flux measured at 20h UTC on 2.8 GHz was 69.8. The planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 5.4). Three hour interval K indices: 32201111 (planetary), 32311111 (Boulder).

The background x-ray flux is below the class A1 level.

At midnight the visible solar disk was spotless. The solar flare activity level was very low. No C class events were recorded during the day.

Coronal mass ejections (CMEs)

November 15-17: No obvious fully or partly Earth directed CMEs were observed in LASCO imagery.

Coronal holes

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

A recurrent coronal hole (CH300) in the southern hemisphere will be in an Earth facing position on November 17-18.

Processed SOHO/EIT 195 image at 00:00 UTC on November 18. The darkest areas on the solar disk are likely coronal holes.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is fair. Propagation on long distance northeast-southwest paths is poor.

Monitoring remarks from a location near N58E06: November 12: During the evening fairly strong signals from east coast USA stations. 1470 WJDY, 1500 WFIF and 1520 WIZZ were all good on their daytime power. The best Trans Atlantic propagation sector was 270-310 degrees.

Forecast

The geomagnetic field is expected to be quiet to unsettled on November 18-19. November 20-21 could see quiet to minor storm conditions due to a high speed stream from CH300.

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) Effects from a CME are likely to be observed at 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.

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
10974 2007.11.16 3   N13W21 0040 DAO spotless at midnight
Total spot count: 3 0  
SSN: 13 0  

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)
2006.09 77.8 14.4 15.6 (+0.0)
2006.10 74.3 10.4 14.2 (-1.4)
2006.11 86.3 21.5 12.7 (-1.5)
2006.12 84.5 13.6 12.1 (-0.6)
2007.01 83.3 16.9 12.0 (-0.1)
2007.02 77.7 10.6 11.6 (-0.4)
2007.03 72.2 4.8 10.8 (-0.8)
2007.04 72.4 3.7 9.9 (-0.9)
2007.05 74.4 11.7 (8.7 predicted, -1.2)
2007.06 73.7 12.0 (7.5 predicted, -1.2)
2007.07 71.6 10.0 (6.7 predicted, -0.8)
2007.08 69.1 6.2 (6.2 predicted, -0.5)
2007.09 67.1 2.4 (6.2 predicted, +0.0)
2007.10 67.4 0.9 (6.7 predicted, +0.5)
2007.11 68.9 (1) 1.2 (2) (7.3 predicted, +0.6)

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.


[DX-Listeners' Club]