Last major update issued on May 17, 2004 at 03:10 UTC.
[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update May 3, 2004)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update May 3, 2004)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update May 3, 2004)]
[Historical solar and geomagnetic data charts 1954-2004 (last update April 28, 2004)]
[Archived reports (last update May 8, 2004)]
The geomagnetic field was quiet on May 16. Solar wind speed ranged between 285 and 333 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 118.3. The planetary A
index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 5.8).
Three hour interval K indices: 22112112 (planetary), 22212222 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight there were 7 spotted regions on the visible disk. The solar flare activity level was very low. No C class events were recorded during the day.
Region 10606 decayed in the leading penumbra, however, a couple of new spots emerged just east of that penumbra.
Region 10609 decayed further and is currently a magnetically simply structured region with the positive and negative polarity spots well separated.
Region 10612 developed further as a weak magnetic delta formed in the northwestern part of the trailing penumbra. C flares are possible.
Region 10613 was quiet and stable.
New region 10614 emerged in the southwest quadrant on May 15 and was numbered the next day by SEC. The region is somewhat interesting as there are three small areas of positive polarity around and near the dominant negative polarity area. C flares are possible today before the region rotate around the southwest limb..
New region 10615 rotated into view at the northeast limb on May 15 and was numbered the day after by SEC.
New region 10616 emerged near the northeast limb on May 16.
May 14-16: No fully or partly Earth directed CME observed.
Coronal hole 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 small, recurrent coronal hole (CH96) in the southern hemisphere will likely rotate into a geoeffective position on May 17.
Processed SOHO/EIT 284 image at 19:05 UTC on May 16. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on May 17-19 and quiet to active on May 20 due effects from a coronal hole stream.
|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 fair to poor. Propagation along long distance north-south paths is poor. Trans Atlantic propagation conditions are monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela). A number of stations from the easternmost parts of Canada and USA were noted with fairly weak signals on other frequencies, a.o. 1420, 1430, 1450, 1140, 1070 kHz).
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|
classification was DAO
at midnight, area 0360
formerly region S404
location was S07W75
|10615||2004.05.16||2||1||N17E64||0060||HSX||formerly region S403|
|Total spot count:||68||49|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2003.11||140.8||67.3||(56.5 predicted, -1.6)|
|2003.12||114.9||46.5||(53.5 predicted, -3.0)|
|2004.01||114.1||37.2||(49.1 predicted, -4.4)|
|2004.02||107.0||46.0||(44.8 predicted, -4.3)|
|2004.03||112.0||48.9||(42.1 predicted, -2.7)|
|2004.04||101.2||39.3||(40.0 predicted, -2.1)|
|2004.05||96.1 (1)||34.8 (2)||(36.8 predicted, -3.2)|
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.