Last major update issued on August 30, 2007 at 05:00 UTC.
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The geomagnetic field was quiet on August 29. Solar wind speed ranged between 470 and 547 km/s (average speed was 508 km/s, decreasing 79 km/s from the previous day).
Solar flux measured at 20h UTC on 2.8 GHz was 69.6. The planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.4). Three hour interval K indices: 20111112 (planetary), 10112111 (Boulder).
The background x-ray flux is below the class A1 level.
At midnight there was 1 spotted region on the visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.
Region 10969 was quiet and stable.
August 27-29: No obvious fully or partly Earth directed CMEs were observed in incomplete LASCO imagery.
history (since late October 2002)
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago
A recurrent coronal hole (CH288) in the southern hemisphere may have been in an Earth facing position on August 28-29.
Processed STEREO 195 image at 19:15 UTC on August 29. The darkest areas on the solar disk are likely coronal holes.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor to fair. Propagation on long distance northeast-southwest paths is poor.
Monitoring remarks from a location near N58E06: August 30: Stations from the Canadian Atlantic provinces, like 1320 CKEC and 930 CJYQ, had the strongest signals of all TA stations. Some stations from the northeastern USA were audible as well. From South America only a few weak signals were present, mostly from stations located in Brazil and Uruguay.
The geomagnetic field is expected to be quiet on August 30-31. There is a chance of a few unsettled intervals on September 1-2 due to effects from CH288.
|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) Effects from a CME are likely to be observed at 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|
|10969||2007.08.21||3||2||S05W30||0100||CHO||classification was HAX at midnight|
|Total spot count:||3||2|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2007.02||77.7||10.6||(11.6 predicted, -0.4)|
|2007.03||72.2||4.8||(11.1 predicted, -0.5)|
|2007.04||72.4||3.7||(10.8 predicted, -0.3)|
|2007.05||74.4||11.7||(10.4 predicted, -0.4)|
|2007.06||73.7||12.0||(10.3 predicted, -0.1)|
|2007.07||71.6||10.0||(10.5 predicted, +0.2)|
|2007.08||69.0 (1)||8.9 (2)||(11.0 predicted, +0.5)|
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% lower.
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.