Last major update issued on June 29, 2004 at 03:40 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 active on June 28. Solar wind speed ranged between 324 and 538 km/sec. A moderately strong high speed stream from coronal hole CH103 began to influence the geomagnetic field after 15h UTC.
Solar flux measured at 20h UTC on 2.8 GHz was 89.4. The planetary A
index was 13 (STAR Ap - based on the mean of three hour interval ap indices: 14.4).
Three hour interval K indices: 33122244 (planetary), 24233334 (Boulder).
The background x-ray flux is at the class B1 level.
At midnight there were 3 spotted regions on the visible disk. The solar flare activity level was low. A total of 7 C class events was recorded during the day. Region 10635 behind the southwest limb was the source of these flares: C1.3 at 01:41, C1.0 at 01:56, C1.8 at 03:24, C2.8 at 04:17, C1.1 at 06:16, C1.0 at 06:52 and C1.6 at 12:12 UTC.
Region 10637 decayed slowly and quietly.
Region 10639 developed slowly and was quiet.
Region 10640 was quiet and stable
June 26-28: A limited number of LASCO images have become available during this interval. There may have been a halo CME during the morning of June 28.
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) was in 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 active on June 29-30 due to a high speed stream from coronal hole CH103 and quiet to unsettled on July 1-2.
|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 to very poor. Propagation along long distance north-south paths is poor. Trans Atlantic propagation conditions are monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela) with a strong signal. Propagation was best towards Venezuela with stations on 1380, 1420, 1500 and 1520 noted with fair signals. 1510 WWZN Boston was the only station from North America and had a fairly weak signal.
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|
|10640||2004.06.27||2||6||S07E56||0040||DAO||reversed polarity region|
|Total spot count:||15||19|
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||98.4 (1)||73.9 (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.