Solar Terrestrial Activity Report

Last update November 26, 2002 at 04:00 UTC.

[Solar and geomagnetic data - last 4 weeks (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update November 2, 2002)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update November 2, 2002)]
[Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update November 2, 2002)]
[Historical solar and geomagnetic data charts 1954-2002 (last update October 13, 2002)]
[Archived reports (last update November 24, 2002)]

Recent activity

The geomagnetic field was quiet to active on November 25. Solar wind speed ranged between 420 and 532 km/sec under the influence of a coronal stream. 

Solar flare activity was low. Solar flux was 136.8, the planetary A index was 17 (STAR Ap - based on the mean of three hour ap indices: 16.5).
Three hour interval K indices: 23344333 (planetary), 23344323 (Boulder).

The background x-ray flux is at the class B5 level.

The above 10 MeV proton flux was enhanced most of the day, the increase in proton levels is associated with the long duration C6 event observed late on Nov.25.

At midnight there were 4 spotted regions on the visible disk. A total of 5 C class events were recorded during the day, including an optically uncorrelated C1.7 event at 23:57 UTC.

Region 10195 decayed and lost its trailing spots. The leading penumbra rotated out of view during the last hour of the day. Flare: C1.2 at 20:33 UTC.
Region 10197 was quiet and stable.
Region 10198 decayed further and appears to be losing all trailing spots. Flares: Long duration C1.3 event peaking at 17:10 and C1.0 at 22:33 UTC.
Region 10200 decayed and lost about half of its penumbral area..
Region 10201 was spotless all day. Flare: C1.3 at 10:42 UTC.
Region 10202 had some small spots emerge during the day, but they disappeared again leaving only a single spot by midnight.

Early on November 26 a small region has rotated into view at the northeast limb. This AXX group was located at N08E82 at 03h UTC.

Coronal mass ejections (CMEs)

November 23 and 25: No obviously geoeffective CMEs noted.

November 24: A large halo CME was observed following a filament eruption in the northeast quadrant. In EIT images the first hints of an eruption in progress could be seen as early as 18:36 UTC. LASCO C2 images began showing a CME at the northeast limb at 20:30 UTC, while the first C3 image had the CME visible starting at 21:18 UTC. The CME quickly became a full halo CME in LASCO C3 images. It is uncertain if Earth will receive an impact from the main part of the CME. If that happens major storm conditions will be possible from the time of the impact and up to 24 hours afterwards. Impact time is estimated at sometime between 15h UTC on Nov. 26 and 06h UTC on Nov.27.

Coronal holes

An extension of the southern polar coronal hole was in a geoeffective position on Nov.23-24. A trans equatorial coronal hole will rotate into a geoeffective position on November 28.

Processed SOHO EIT 284 image at 19:06 UTC on November 25. The black areas on the solar disk are coronal holes.

Forecast

The geomagnetic field is expected to be quiet to unsettled most of Nov.26. Another coronal stream could reach Earth late on Nov.26 and cause unsettled to active conditions. The CME observed late on Nov.24 could reach Earth late on Nov.26 or early on Nov.27 and cause unsettled to major storm conditions. The possible presence of a coronal stream when this CME arrives could cause the disturbance to be less intense. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor.

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)

Composite image based on a SOHO/MDI continuum image and overlaid by a coronal hole image. Region numbering has been included.

Data for all numbered solar regions according to the Solar Region Summary provided by SEC/NOAA. Comments are my own, as is the STAR spot count (spots observed at or just prior to 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 UT observed solar flux value at 2800 MHz.
2) Unofficial, accumulated value based on the Boulder (SEC/NOAA) sunspot number. The official international sunspot number is typically 25-45% less.

This report has been prepared by Jan Alvestad. It is based partly on my own observations and interpretations, and partly on data from sources noted in solar links. Comments and suggestions are always welcome.