Solar Terrestrial Activity Report

Last major update issued on November 13, 2003 at 04:40 UTC. Minor update posted at 12:54 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 unsettled to minor storm on November 12. Solar wind speed ranged between 607 and 761 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 98.7. The planetary A index was 26 (STAR Ap - based on the mean of three hour interval ap indices: 27.9).
Three hour interval K indices: 44454443 (planetary), 54454443 (Boulder).

The background x-ray flux is at the class B3 level.

At midnight there was 1 spotted region on the visible disk. Solar flare activity was low. A total of 4 C class events were recorded during the day. Early on November 13 a new region has emerged at N06E67 with a single HRX spot. Old region 10484 appears to be rotating into view at the east limb near N04E85. This region was the source of a C1.8 flare at 09:38 and a C2.3 flare at 13:52 UTC. Another region, not yet visible and further north on the northeast limb, produced a C1.0 flare at 22:01 UTC.

Region 10498 decayed slowly and is rotating out of view at the northwest limb. Flare: C3.2 at 18:19 UTC.

Comment added at 07:14 UTC on November 13: Old region 10484 at the east limb was the source of an impulsive M1.6 flare at 05:01 UTC. No significant CME has been observed in LASCO images after this event.

Comment added at 10:16 UTC: Old region 10484 produced a long duration M1.4 event peaking at 09:29 UTC. By 09:54 UTC a bright CME was visible over most of the east limb in LASCO C2.

Comment added at 12:54 UTC: The background x-ray flux is up to the class C2 level as the region at the east limb rotates into view. Early magnetograms indicate that the region is complex with mixed polarities and at least one magnetic delta structure. One or two large penumbrae are visible. Major flares are possible.

The ongoing geomagnetic disturbance intensified after 11h UTC and minor to major storming is currently being observed.

Coronal mass ejections (CMEs)

November 12: A full halo CME was observed in LASCO C3 images beginning at 11:18 UTC. The distribution of the ejected material indicates that the source was about 5 days behind the northeast limb. This is the expected position of old region 10488.

November 11: A full halo CME was observed in LASCO C3 images beginning at 02:42 UTC. The distribution of the ejected material indicates that the source was region 10486 several days behind the southwest limb.
Another full halo CME was observed in LASCO C3 images beginning at 15:18 UTC. The source of this CME was likely the M1.6 flare in region 10498. The CME was fast (above 1300 km/sec) in the core part, the slower outer edge could reach the Earth on November 14. In the presence of a high speed stream the CME is not likely to cause any significant disturbance.

November 10: 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) will be in a geoeffective position on November 9-14. The coronal hole is best defined in the easternmost and westernmost parts and has increased its area during the last solar rotation.

Processed SOHO/EIT 284 image at 01:06 UTC on November 13. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be unsettled to minor storm on November 13-17 due to a high speed stream from coronal hole CH66.

Long distance low frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is very poor to useless. Propagation along long distance north-south paths is poor to very poor. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay with a weak signal].

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.
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.

Monthly solar cycle data

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.