Last major update issued on December 26, 2003 at 03:55 UTC.
[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update December 2, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update December 2, 2003)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update December 2, 2003)]
[Historical solar and geomagnetic data charts 1954-2003 (last update October 15, 2003)]
[Archived reports (last update December 17, 2003)]
The geomagnetic field was quiet to unsettled on December 25. Solar wind speed ranged between 349 and 404 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 139.1. The planetary A
index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 7.8).
Three hour interval K indices: 21122322 (planetary), 21123322 (Boulder).
The background x-ray flux is at the class B3 level.
At midnight there were 2 spotted regions on the visible disk. Solar flare activity was low. A total of 8 C class events were recorded during the day. Now spotless region 10525 produced a C3.6 flare at 03:01, a C1.9 flare at 04:01 and a C1.2 flare at 05:27 UTC. A C1.5 flare at 01:48 UTC had its source in a spotless region in the southeast quadrant near the central meridian.
Region 10528 did not change much and remains fairly simple structured with only minor polarity intermixing observed. An M class flare is
possible. Flares: C5.3 at 02:31, C5.3 long duration event peaking at 08:25, C1.5 at 11:50 and
C1.2 at 18:05 UTC.
New region 10532 emerged in the southeast quadrant on December 24 and was numbered the next day be SEC. The region developed slowly on December 25.
December 23-25: No partly or fully earth directed CMEs observed.
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 recurrent trans equatorial coronal hole (CH73) will likely rotate into a geoeffective position on December 28-29.
Processed SOHO/EIT 284 image at 07:06 UTC on December 25. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be mostly quiet until December 31 when a high speed stream from coronal hole CH73 is likely to cause unsettled to minor storm conditions.
Long distance low frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is fair to good and improving. 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 Vibración (Venezuela) at first, then WLAM Lewiston ME with two other US stations noted at times. Lots of US and Canadian station noted on other frequencies].
|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.
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|
formerly region S329
classification was DSO
at midnight, area 0050
|Total spot count:||28||32|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2003.06||129.3||77.4||(65.1 predicted, -2.5)|
|2003.07||127.7||83.3||(61.8 predicted, -3.3)|
|2003.08||122.1||72.7||(58.8 predicted, -3.0)|
|2003.09||112.2||48.7||(56.9 predicted, -1.9)|
|2003.10||151.7||65.6||(54.1 predicted, -2.8)|
|2003.11||140.8||67.2||(51.4 predicted, -2.7)|
|2003.12||114.1 (1)||67.8 (2)||(48.9 predicted, -2.5)|
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.