Last major update issued on May 13, 2005 at 04:35 UTC. Important update posted at 19:10 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 2, 2005)]
The geomagnetic field was quiet to active on May 12. Solar wind speed ranged between 457 and 562 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 117.4. The planetary
index was 17 (STAR Ap - based on the mean of three hour interval ap
Three hour interval K indices: 34342333 (planetary), 24343223 (Boulder).
The background x-ray flux is at the class B3 level.
At midnight there were 4 spotted regions on the visible solar disk. The solar flare activity level was moderate. A total of 14 C and 2 M class events was recorded during the day.
Region 10758 remained complex with at least
one magnetic delta structure within the main penumbral area. Further M class flares are possible. Flares:
C2.7 at 00:17, C4.2 at 00:30, C1.9 at 01:47, C1.0 at 05:24, C1.4 at 11:18, C1.2 at 13:19, C3.0 at 13:55 and C2.4 at 19:53 UTC.
Region 10759 added some small trailing spots while the main penumbra became more symmetrical. Flares: C9.4/2B at 01:13, C2.0 at 03:09, C1.4 at 06:59, M1.6/2B at 07:33, C1.6 at 17:05, M1.4/1N at 17:41 and C2.1 at 22:55 UTC.
Region 10762 decayed slightly as the opposite polarity areas displayed increased separation.
New region 10763 was first observed on May 10 and was numbered by SEC two days later. This region is somewhat complex with a small magnetic delta structure in a trailing penumbra. Flare: C2.0 at 21:48 UTC.
Comment added at 19:10 UTC on May 13: Region 10759 produced a major M8.0 long duration event peaking at 16:57 UTC. A bright and fast CME aimed directly at Earth was first observed in LASCO C2 images at 17:22 and in C3 at 17:42 UTC. This CME will likely reach Earth sometime between the last hours of May 14 and early evening of May 15 (a better time estimate will be posted later when further frames displaying the CME become available. A severe geomagnetic storm is likely with max. planetary K index reaching 8 or 9.
May 10 and 12: No obviously fully or partly potentially geoeffective CMEs were observed.
May 11: A slow full halo CME was observed after an M flare in region 10758 during the evening.
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 narrow elongated coronal hole (CH164) in the northern hemisphere near the equator was in an Earth facing position on May 10-12.
Processed SOHO/EIT 284 image at 01:06 UTC on May 13. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected be quiet to minor storm on May 13-15, first due to coronal hole effects. A CME observed on May 11 will likely reach Earth after noon on May 14.
|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 very poor. Propagation along long distance north-south paths is poor to fair. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay. On other frequencies stations from Brazil (the strongest trans Atlantic signal from Rádio Cristal on 1350 kHz) and Uruguay (930 Radio Monte Carlo and 1590 Emisora Real) were heard.
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|
|10760||2||S08W59||0080||BXO||part of region 10758|
formerly region S547
formerly region S545
|Total spot count:||50||82|
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||111.6 (1)||30.5 (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.