Last major update issued on June 26, 2004 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 June 2, 2004)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update June 2, 2004)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update June 2, 2004)]
[Historical solar and geomagnetic data charts 1954-2004 (last update April 28, 2004)]
[Archived reports (last update June 21, 2004)]
The geomagnetic field was quiet to unsettled on June 25. Solar wind speed ranged between 286 and 364 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 102.9. The planetary A
index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 5.3).
Three hour interval K indices: 00012231 (planetary), 11012121 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight there were 3 spotted regions on the visible disk. The solar flare activity level was low. A total of 1 C class event was recorded during the day.
Region 10635 decayed further and will be rotating over the southwest limb today and tomorrow. There is still a magnetic delta structure
in the main trailing penumbra. Flare: C2.5 at 11:32 UTC.
Region 10637 developed slowly and has quite a few small spots.
Spotted regions not numbered by NOAA/SEC:
[S424] A new region emerged in the northeast quadrant on June 25. Polarities are currently reversed. Location at midnight: N07E35.
June 23-25: Very few LASCO images available. A weak CME may have been associated with a C1 event in region 10635 on June 24.
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 (CH103) will rotate into a geoeffective position on June 26-27.
Processed SOHO/EIT 284 image at 13:05 UTC on June 15. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on June 26-27 and quiet to active on June 28-30 due to a high speed stream from coronal hole CH103.
|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.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor. Propagation along long distance north-south paths is fair to good. Trans Atlantic propagation conditions are monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay and Radio Vibración (Venezuela). Many stations from Brazil were noted on other frequencies, particularly before 01:30 UTC. Fair to occasionally good signals could be heard on 1510, 1540, 1560 and 1570 kHz. The best trans Atlantic signal, without comparison, was from Rádio Sociedade (Bahia, Brazil) on 740 kHz. As usual 1510 WWZN Boston had the best signal from North America, only a few stations from Newfoundland were heard otherwise.
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|
|10634||2004.06.13||1||N12W88||0120||HAX||rotated out of view|
classification was FAO
at midnight, area 0300,
location was S10W70
classification was BXO
at midnight, area 0020
|Total spot count:||43||20|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2003.12||114.9||46.5||(54.4 predicted, -2.3)|
|2004.01||114.1||37.2||(50.5 predicted, -3.9)|
|2004.02||107.0||46.0||(46.2 predicted, -4.3)|
|2004.03||112.0||48.9||(43.5 predicted, -2.7)|
|2004.04||101.2||39.3||(41.4 predicted, -2.1)|
|2004.05||99.8||41.5||(38.2 predicted, -3.2)|
|2004.06||98.8 (1)||68.7 (2)||(35.3 predicted, -2.9)|
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 some of these solar data sources. All time references are to the UTC day. Comments and suggestions are always welcome.