Last major update issued on May 16, 2004 at 03:40 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 to active on May 15. Solar wind speed ranged between 298 and 360 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 115.3. The planetary A
index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 10.1).
Three hour interval K indices: 42222222 (planetary), 43223322 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight there were 6 spotted regions on the visible disk. The solar flare activity level was low. A single C class event was recorded during the day.
Region 10606 decayed further and was quiet.
Region 10609 developed early in the day, then began to decay. There are still a few small positive polarity spots at the northeastern edge of the large leading penumbra, other than that the region has simplified. A minor M class flare is possible. Flare: C2.2 at 14:46 UTC.
Region 10612 developed further and more than doubled the penumbral area. C flares are possible.
Region 10613 was quiet and stable.
Spotted regions not numbered by NOAA/SEC:
[S403] This region rotated into view at the northeast limb on May 15. Location at midnight: N17E78.
[S404] A new region emerged in the southwest quadrant on May 15. Location at midnight: S08W59.
May 13-15: 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 15. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to active on May 15 and quiet to unsettled on May 16-17.
|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 poor to very 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). WWZN Boston on 1510 kHz was there this night as well and had a weak signal. Only VOCM on 590 kHz had a decent signal of the few North American stations observed.
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 HAX
at midnight, area 0090
classification was DKO
area was 0130
|Total spot count:||67||59|
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||94.6 (1)||30.0 (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.