Solar Terrestrial Activity Report

Last major update issued on November 18, 2003 at 05:05 UTC. Minor update posted at 10:04 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, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update November 4, 2003)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update November 4, 2003)]
[Historical solar and geomagnetic data charts 1954-2003 (last update October 15, 2003)]
[Archived reports (last update November 12, 2003)]

Recent activity

The geomagnetic field was active to minor storm on November 17. Solar wind speed ranged between 624 and 785 km/sec under the influence of a high speed stream from coronal hole CH66.

Solar flux measured at 20h UTC on 2.8 GHz was 121.0. The planetary A index was 34 (STAR Ap - based on the mean of three hour interval ap indices: 35.3).
Three hour interval K indices: 54455544 (planetary), 54454534 (Boulder).

The background x-ray flux is at the class C1 level.

At midnight there were 4 spotted regions on the visible disk. Solar flare activity was moderate. A total of 9 C and 2 M class events were recorded during the day.

Region 10501 developed slowly and still has 3 magnetic delta structures. There is not much separating opposite polarity umbrae in the 3 largest penumbrae. Further M class flares are likely and there is a chance of a major flare. Flares: M1.2 at 01:34, C2.2 at 02:13, M4.2/1N at 09:05 (associated with a weak type II radio sweep), C2.5 at 12:47, C1.7 at 21:45 (note that another longer duration event occurred at the southeast limb a few minutes earlier) UTC.
New region 10505 rotated into view at the southeast limb on November 16 and was numbered the next day by SEC.

Spotted regions not numbered by NOAA/SEC:
[S305] This region emerged quickly late on November 17 just east of spotless region 10504. Location at midnight: N04E57. A single spot was visible at midnight, several spots in a DAO configuration was visible a couple of hours later.
[S306] A new region rotated partly into view at the southeast limb late on November 17. More spots should become visible as the region rotates into better view. This region, or another one trailing this region, could be capable of M class flaring. Location at midnight: S21E84.

[S307] One hour into November 18 a fairly large penumbra became visible at the northeast limb at N09E88. Flares: C2.2 at 05:27, C2.5 at 13:49, C1.3 at 15:48 and C3.1 at 20:09 UTC.

Comment added at 08:17 UTC on November 18: Region 10501 was the source of an M3.2 long duration event peaking at 07:52 UTC. A fair amount of material was observed moving south and an earth directed CME is likely to have been associated with the LDE. Based on recent CMEs from this region, this CME could reach Earth early on November 20. A better estimate as to the arrival time and severity of the solar storm will be posted when LASCO images become available.

Another, possibly larger, M class event is in progress as I write this.

Comment added at 08:50 UTC: The M3.2 event mentioned above triggered activity in filaments to the west and southwest of region 10501 and caused a bright and large area M3.8 long duration event peaking at 08:25 UTC. I wouldn't be surprised if this resulted in a large, earth directed CME. We can expect minor to severe geomagnetic storming from late on November 19 or early on November 20.

Comment added at 10:04 UTC: The two M3 events in region 10501 were associated with both type II and IV radio sweeps.

A large long duration event is currently in progress at the southeast limb. This could easily become a major flare. The x-ray flux is currently increasing at the M4 level.

Coronal mass ejections (CMEs)

November 17: A full, relatively faint, CME was observed after an M4 flare in region 10501 at 09:05 UTC. The CME could reach Earth during the first half of November 19.

November 15-16: No partly or fully 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

A well defined recurrent trans equatorial coronal hole (CH66) was in a geoeffective position on November 9-14. A coronal hole (CH67) in the northern hemisphere may have been in a geoeffective position on November 15-16. Another coronal hole (CH68) in the northern hemisphere could rotate into a geoeffective position on November 20-21.

Processed SOHO/EIT 284 image at 01:05 UTC on November 18. The darkest areas on the solar disk are likely coronal holes.


The geomagnetic field is expected to be unsettled to active on November 18 due to a high speed stream from coronal hole CH66. A CME could arrive during the first half of November 19 and cause unsettled to minor storm, perhaps briefly reaching major storm conditions.

Long distance low 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 fair. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay, at times with interference from an unidentified station from Brazil. Quite a few signals from Brazil on other frequencies, e.g. Rádio Bandeirantes (Rio de Janeiro) on 1360 kHz].

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.

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
Location at midnight Area Classification Comment
10501 2003.11.13 25 27 N03E22 0370 DKI gamma-delta
10502 2003.11.14 1   N07E04 0000 AXX ?? region is spotless
10503 2003.11.15 3   N17W18 0010 BXO spotless
10504 2003.11.16     N04W64     plage
10505 2003.11.17 3 3 S22E58 0020 CSO formerly region S304
S303 emerged on
    N12W40     plage
S305 emerged on
  1 N04E57 0010 HRX  
S306 visible on
  3 S22E85 0030 CAO  
S307 visible on
    N09E88     not counted, visible
after midnight
Total spot count: 32 34
SSN: 72 74

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)
2002.10 167.0 97.5 90.5 (-4.1)
2002.11 168.7 95.5 85.2 (-5.3)
2002.12 157.2 80.8 82.0 (-3.2)
2003.01 144.0 79.7 80.9 (-1.1)
2003.02 124.5 46.0 78.5 (-2.4)
2003.03 131.4 61.1 74.1 (-4.4)
2003.04 126.4 60.0 70.3 (-3.8)
2003.05 115.7 55.2 (66.8 predicted, -3.5)
2003.06 129.3 77.4 (63.0 predicted, -3.8)
2003.07 127.7 85.0 (59.3 predicted, -3.7)
2003.08 122.1 72.7 (56.3 predicted, -3.0)
2003.09 112.2 48.8 (54.3 predicted, -2.0)
2003.10 151.7 65.6 (51.6 predicted, -2.7)
2003.11 119.9 (1) 36.8 (2) (48.9 predicted, -2.7)

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 sources noted in solar links. All time references are to the UTC day. Comments and suggestions are always welcome.

[DX-Listeners' Club]