Solar Terrestrial Activity Report

Last major update issued on November 20, 2003 at 05:30 UTC. Minor update posted at 14:25 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 quiet to active on November 19. Solar wind speed ranged between 451 and 646 km/sec.

Solar flux measured at 20h UTC on 2.8 GHz was 155.1. The planetary A index was 14 (STAR Ap - based on the mean of three hour interval ap indices: 15.0).
Three hour interval K indices: 23443332 (planetary), 23334332 (Boulder).

The background x-ray flux is at the class B9 level.

At midnight there were 5 spotted regions on the visible disk. Solar flare activity was moderate. A total of 9 C and 1 M class events were recorded during the day.

Region 10501 decayed, particularly in the southern spot section. The positive polarity umbra in the northern penumbra could soon become a separate penumbra. While there are still 3 magnetic delta structures, the region appears to be simplifying. Minor M class flares are possible. Flares: M1.7/1N at 04:01, C8.8/1F long duration event peaking at 08:17, C4.9 at 09:33, C2.8 at 11:46 and C9.1 at 15:19 UTC.
Region 10505 decayed slightly and was quiet.
Region 10506 decayed slowly losing almost half of its penumbral area. Some polarity intermixing is evident.
Region 10507 was mostly unchanged and remains capable of producing major flares. There is a strong magnetic delta structure within the main penumbra.
New region 10508 rotated into view at the southeast limb. This is old region 10486 and it is much smaller now compared to the last time we observed it at the southwest limb over two weeks ago. While the region is still complex in magnetograms, no magnetic delta structures have been observed. Flares: C2.4 at 01:16, C2.3 at 04:20, C3.9 at 14:19, C1.1 at 21:26 and C2.3 at 22:10 UTC.

Comment added at 07:53 UTC on November 20: Region 10501 produced an impulsive major M9.6 flare at 07:47 UTC. If there was a CME associated with this event another update will be posted when relevant LASCO data become available. The region is near the center of the visible disk and any CME from this position is likely to impact the Earth.

Comment added at 08:03 UTC: A strong solar wind shock was observed at SOHO at 07:27 UTC with a sudden increase in solar wind speed from 443 to 639 km/sec.

Comment added at 11:45 UTC: The solar storm which arrived at Earth near 08h UTC is causing major to severe geomagnetic storming. The interplanetary magnetic field at ACE is currently extremely strongly southwards and this could result in very severe geomagnetic storming (Kp8 or 9).

Region 10505 has been developing moderately quickly today and may soon become capable of producing C and even minor M class flares.

Comment added at 14:25 UTC: The geomagnetic disturbance continues to intensify. Currently the IMF is exceptionally strongly southwards. This solar storm promises to be among the 5 most intense during this solar cycle. The planetary A index for the 09-12h UTC interval was 122 and should go considerably higher for the 12-15h UTC interval.

Coronal mass ejections (CMEs)

November 19: No partly or fully earth directed CMEs observed.

November 18: A fairly faint full halo CME was observed after an M3.2 long duration event in region 10501 at 07:52 UTC. A faster and brighter halo CME was observed in LASCO images following an M3.9 long duration event in region 10501 at 08:31 UTC. These CMEs will combine into one and could reach Earth early on November 20.

A bright, fast and very large partial halo CME was observed after the long duration M4.5 event in old region 10486 just behind the southeast limb at 10:11 UTC.

November 17: A full, relatively faint, CME was observed after an M4 flare in region 10501 at 09:05 UTC.

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 coronal hole (CH68) in the northern hemisphere could rotate into a geoeffective position on November 20-21.

Processed SOHO/EIT 284 image at 19:05 UTC on November 19. The darkest areas on the solar disk are likely coronal holes.


The geomagnetic field is expected to be quiet to major storm on November 20 as a CME is likely to impact the Earth during the first half of the day. Unsettled to active is expected for November 21-22. A fairly weak high speed stream from coronal hole CH68 could influence the geomagnetic field on November 23-25.

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 poor. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay and Cadena Peruana de Noticias].

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 22 20 N03W05 0380 DKO beta-gamma-delta
10502 2003.11.14     N07W22     plage
10503 2003.11.15     N17W44     plage
10504 2003.11.16 3   N04W90
0030 CRO SEC has reused region
number 10504
region was spotless
all day
10505 2003.11.17 3 2 S22E32 0030 CRO classification was HRX
at midnight, area 0010
10506 2003.11.18 10 8 S21E59 0110 DSO area was 0040
at midnight
10507 2003.11.18 11 22 N10E62 0890 EKI beta-gamma-delta
classification was DKC
at midnight
10508 2003.11.19 5 19 S17E75 0700 EKO beta-gamma
classification was DAI
at midnight, area 0450
S303 emerged on
    N12W66     plage
S305 emerged on
    N04W83     spotless
Total spot count: 54 71
SSN: 114 121

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)
2003.11 123.0 (1) 43.6 (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]