Last major update issued on July 16, 2007 at 03:10 UTC.
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The geomagnetic field was quiet to active on July 15. Solar wind speed ranged between 459 and 636 km/s (average speed was 531 km/s, increasing 70 km/s over the previous day) under the influence of a high speed stream from CH277.
Solar flux measured at 20h UTC on 2.8 GHz was 74.7. The planetary A index was 13 (STAR Ap - based on the mean of three hour interval ap indices: 12.6). Three hour interval K indices: 44322212 (planetary), 34322212 (Boulder).
The background x-ray flux is at the class A2 level.
At midnight there were 2 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 10963 decayed slowly and was quiet.
Region 10964 decayed further and losst the trailing spots.
July 13-15: No obvious fully or partly Earth directed CMEs were observed.
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 (CH278) in the southeastern quadrant could rotate into a potentially geoeffective position on July 15-16.
Processed SOHO/EIT 195 image at 23:15 UTC on July 15. 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 very poor. Propagation on long distance northeast-southwest paths is poor.
Monitoring remarks from a location near N58E06: July 16: 950 kHz Radio Belgrano and 1600 kHz Rádio 9 de Julho had the best signals of only a few audible stations from South America.
The geomagnetic field is expected to be quiet on July 16-17. A high speed stream from CH278 could arrive on July 18 and cause some unsettled and active intervals that day and on July 19.
|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|
|10963||2007.07.07||16||13||S06W27||0270||EAI||classification was EAO at midnight|
|10964||2007.07.13||5||2||N02W54||0050||CSO||classification was HAX at midnight, area 0020|
|Total spot count:||21||15|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2007.01||83.3||16.9||(11.9 predicted, -0.2)|
|2007.02||77.7||10.6||(11.3 predicted, -0.6)|
|2007.03||72.2||4.8||(10.8 predicted, -0.5)|
|2007.04||72.4||3.7||(10.8 predicted, unchanged)|
|2007.05||74.4||11.7||(10.6 predicted, -0.2)|
|2007.06||73.7||12.0||(10.7 predicted, +0.1)|
|2007.07||74.7 (1)||11.6 (2)||(11.0 predicted, +0.3)|
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.