Last major update issued on December 25, 2003 at 04:40 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 24. Solar wind speed ranged between 395 and 472 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 138.9. The planetary A
index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 9.4).
Three hour interval K indices: 12223332 (planetary), 11111322 (Boulder).
The background x-ray flux is at the class B4 level.
At midnight there were 3 spotted regions on the visible disk. Solar flare activity was low. A total of 4 C class events were recorded during the day. Now spotless region 10531 produced a C1.2 flare at 10:06 UTC.
Region 10525 decayed quickly and could soon become spotless. Flare: C1.2 at
Region 10528 developed quickly in the trailing spot section. An M class flare is possible. Flares: C1.5 at 23:16 and C1.8 beginning at 23:49 UTC and peaking 00:02 UTC on December 25.
Spotted regions not numbered by NOAA/SEC:
[S329] A new region emerged in the southeast quadrant on December 24. Location at midnight: S12E13.
December 22-24: 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
No obvious coronal holes will be rotating into geoeffective positions during the next few days.
Processed SOHO/EIT 284 image at 19:06 UTC on December 24. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be mostly quiet until December 31.
Long distance low frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is fair and slowly improving. Unless something unexpected happens good conditions will be likely from December 26-31. 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. Several US and Canadian east coast stations were heard on other frequencies with good signals from a.o. 1130 WBBR New York and 1510 WWZN Boston].
|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|
classification was CSO
at midnight, area 0030
classification was FKI
at midnight, area 0800
|Total spot count:||60||50|
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||113.1 (1)||66.0 (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.