Last major update issued on October 22, 2006 at 04:45 UTC.
geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update October 2, 2006)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update October 2, 2006)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update October 2, 2006)]
[Historical solar and geomagnetic data charts 1954-2005 (last update March 3, 2006)]
[Archived reports (last update October 2, 2006)]
The geomagnetic field was quiet to active on October 21. Solar wind speed ranged between 521 and 635 km/s (all day average 579 km/s - increasing 207 km/s over the previous day) under the influence of a high speed stream from CH244.
Solar flux measured at 20h UTC on 2.8 GHz was 74.7. The planetary A index was 15 (STAR Ap - based on the mean of three hour interval ap indices: 14.6). Three hour interval K indices: 32333432 (planetary), 32433432 (Boulder).
The background x-ray flux is at the class A4 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 10917 decayed early in the day then developed very quickly after noon. C flares are possible.
October 19-21: No obvious partly or fully Earth directed CMEs were detected in LASCO imagery.
Coronal hole 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 well defined large, recurrent trans equatorial coronal hole (CH244) was in an Earth facing position on October 16-18. The southernmost extensions of a new coronal hole in the northern hemisphere rotated across the central meridian on October 20-21. A small poorly defined coronal hole (CH245) in the northern hemisphere could rotate into an Earth facing position on October 24.
Processed SOHO/EIT 284 image at 19:06 UTC on October 21. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on October 22-23 under the influence of a high speed stream from CH244. A Mostly quiet conditions are likely for the remainder of the month as the recurrent coronal hole CH241 has decayed substantially. There is a chance of some unsettled intervals on October 27 and 28 due to effects from CH245.
|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.
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 poor.
Monitoring remarks from a location near N58E05: Only a few of the most common station from the easdt coast of North America were audible. Propagation favored stations from Venezuela and Colombia, although no strong signals were noted from that area.
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|
|10917||2006.10.19||6||19||S05W33||0070||CSO||classification was DAC at midnight, area 0120|
|Total spot count:||6||19|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2006.04||89.0||30.2||(17.1 predicted, -0.2)|
|2006.05||80.9||22.2||(16.8 predicted, -0.3)|
|2006.06||76.5||13.9||(15.1 predicted, -1.7)|
|2006.07||75.7||12.2||(13.2 predicted, -1.9)|
|2006.08||79.0||12.9||(12.8 predicted, -0.4)|
|2006.09||77.8||14.5||(12.6 predicted, -0.2)|
|2006.10||74.0 (1)||9.0 (2)||(11.6 predicted, -1.0)|
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.