Last major update issued on July 20, 2007 at 04:30 UTC.
geomagnetic data - last month (updated daily)]
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The geomagnetic field was quiet on July 19. Solar wind speed ranged between 276 and 362 km/s (average speed was 334 km/s, decreasing 18 km/s from the previous day).
Solar flux measured at 20h UTC on 2.8 GHz was 68.3. The planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.1). Three hour interval K indices: 10002111 (planetary), 00112111 (Boulder).
The background x-ray flux is below the class A1 level.
At midnight the visible solar disk was spotless. The solar flare activity level was very low. No C class events were recorded during the day.
July 17-19: 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 was in a potentially geoeffective position on July 15-16. A trans equatorial recurrent coronal hole (CH279) will likely rotate into an Earth facing position on July 23-24.
Processed STEREO 195 image at 23:05 UTC on July 19. 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. Propagation on long distance northeast-southwest paths is fair to good.
Monitoring remarks from a location near N58E06: July 20: Lots of stations from Argentina, Brazil, Paraguay and Uruguay were heard during the hour after LSR, particularly between 700 and 1250 kHz. The Buenos Aires stations on 710, 870, 910 and 950 kHz all had excellent peaks. 920 kHz had a mix of Rádio Novo Tempo and presumed Radio Nacional Paraguay.
The geomagnetic field is expected to be quiet to unsettled on July 20-21, perhaps with a few active intervals due to effects from CH278. Quiet conditions are likely on July 22-24.
|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||2||S04W86||0110||HSX||rotated out of view|
|Total spot count:||2||0|
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||73.9 (1)||14.0 (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.