Last major update issued on May 30, 2005 at 04:20 UTC.
geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update May 6, 2005)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update May 6, 2005)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update May 6, 2005)]
[Historical solar and geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports (last update May 15, 2005)]
The geomagnetic field was quiet to major storm on May 29. Solar wind speed ranged between 311 and 545 km/sec. A solar wind shock was observed at SOHO at 09:15 UTC. This was the arrival of the first halo CME observed on May 26. After this shock the interplanetary magnetic field was northwards until 15h UTC, then the IMF was mostly weakly to moderately southwards until just before 21h UTC. At 20:51 UTC SOHO recorded a possible solar wind shock, this may have been the arrival of the CME observed late on May 26. After 21:30 UTC the IMF was strongly southwards.
Solar flux measured at 20h UTC on 2.8 GHz was 92.7. The planetary
index was 22 (STAR Ap - based on the mean of three hour interval ap
Three hour interval K indices: 34332336 (planetary), 33333335 (Boulder).
The background x-ray flux is at the class B1 level.
At midnight there were 3 spotted regions on the visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.
Region 10767 decayed further and was quiet.
Region 10769 decayed and could become spotless today.
New region 10770 emerged in the northeast quadrant.
May 27-29: No obviously fully or partly potentially geoeffective CMEs were observed.
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 coronal hole (CH168) in the southern hemisphere was in an Earth facing position on May 29. A recurrent coronal hole (CH169) in the northern hemisphere will rotate into an Earth facing position on June 2-3.
Processed SOHO/EIT 284 image at 01:06 UTC on May 30. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be unsettled to minor storm on May 30, becoming quiet to unsettled on May 31. Unsettled to active conditions are possible on June 1-2 due to a high speed stream from CH168.
|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 good. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant stations tonight: Before 02h UTC several stations from Brazil, including Rádio Papacasa, were audible. Near local sunrise Radio Cristal del Uruguay was dominant. Radio Champaquí (Argentina) had a fair signals at times on 1510 kHz after the Brazilian stations disappeared. A few stations from North America were noted in the 1600-1700 kHz range at about 02h UTC.
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|
|10769||2005.05.28||1||2||S07E69||0010||AXX||classification was BXO at midnight|
|10770||2005.05.29||4||5||N12E00||0020||CSO||area was 0030 at midnight|
|Total spot count:||25||40|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2004.11||113.2||43.5||(34.8 predicted, -1.1)|
|2004.12||94.5||17.9||(33.4 predicted, -1.4)|
|2005.01||102.2||31.3||(30.9 predicted, -2.5)|
|2005.02||97.2||29.1||(28.3 predicted, -2.6)|
|2005.03||89.9||24.8||(26.5 predicted, -1.8)|
|2005.04||86.0||24.4||(24.6 predicted, -1.9)|
|2005.05||99.6 (1)||60.4 (2)||(22.0 predicted, -2.6)|
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.