Solar Terrestrial Activity Report

Last major update issued on November 25, 2003 at 04:10 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 22, 2003)]

Recent activity

The geomagnetic field was quiet to active on November 24. Solar wind speed ranged between 462 and 615 km/sec. Until about 11:40 UTC at SOHO the main solar wind influence was from coronal hole CH68, then a high speed stream from coronal hole CH69 began to dominate. Early on November 25 solar wind speed reached nearly 700 km/sec.

Solar flux measured at 20h UTC on 2.8 GHz was 177.3. The planetary A index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 12.9).
Three hour interval K indices: 22324333 (planetary), 22223233 (Boulder).

The background x-ray flux is at the class B6 level.

At midnight there were 10 spotted regions on the visible disk. Solar flare activity was low. A total of 7 C class events were recorded during the day.

Region 10501 decayed further. The region will rotate out of view late today. Flares: C2.6 at 04:56 and C1.1 at 17:22 UTC.
Region 10505 was spotless early in the day, then reemerged with a couple of spots. The region quickly decayed around noon and was spotless until late in the day when a single small spot became visible.
Region 10506 reemerged with a few spots and developed slowly all day.
Region 10507 decayed losing a fair amount of penumbra in the southern and western parts. Several small spots emerged in the trailing negative polarity area. An isolated major flare is possible as there is still a magnetic delta structure in the northern part of the main penumbra.
Region 10508 decayed slowly. Several of the southernmost spots disappeared. Flares: C1.7 at 00:47, C1.3 at 12:10 and C2.3 at 20:21 UTC.
New region 10509 rotated into view at the southeast limb on November 22 and was numbered two days later by SEC. The region added several small spots late in the day. Flare: C2.3 at 18:54 UTC.
New region 10510 rotated into view at the southeast limb on November 23 and was numbered by SEC the next day. Flare: C1.1 at 04:45 UTC.

Spotted regions not numbered by NOAA/SEC:
[S309] This region was split off from region 10508 on November 23 and developed slowly on November 24. Location at midnight: S13E03.
[S311] A new region emerged fairly quickly in the northeast quadrant on November 24. Location at midnight: N06E45.
[S312] A new region emerged late on November 24 in the southeast quadrant. Location at midnight: S14E38.

Coronal mass ejections (CMEs)

November 22-24: 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 new and developing coronal hole (CH69) in the southern hemisphere was in a geoeffective position on November 22.

Processed SOHO/EIT 284 image at 01:05 UTC on November 25. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be unsettled to active on November 25 due to a high speed stream from coronal hole CH69, quiet to unsettled is likely on November 26-27.

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 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. 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.

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.