Last major update issued on March 25, 2004 at 04:45 UTC.
[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update March 2, 2004)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update March 2, 2004)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update March 2, 2004)]
[Historical solar and geomagnetic data charts 1954-2003 (last update January 16, 2004)]
[Archived reports (last update March 11, 2004)]
The geomagnetic field was quiet on March 24. Solar wind speed ranged between 311 and 382 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 119.4. The planetary A
index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 5.4).
Three hour interval K indices: 11122210 (planetary), 11012221 (Boulder).
The background x-ray flux is at the class B4 level.
At midnight there were 6 spotted regions on the visible disk. The solar flare activity level was moderate. A total of 4 C and 1 M class events was recorded during the day.
Region 10574 decayed slowly and was quiet.
Region 10577 developed positive polarity spots just north of the negative polarity spot.
Region 10578 was mostly unchanged and remains capable of producing a minor M class flare. Flares: C5.7 at 14:26 and C1.9 at 21:38 UTC.
New region 10580 emerged in the southwest quadrant near the central meridian.
New region 10581 rotated into view at the southeast limb.
Spotted regions not numbered by NOAA/SEC:
[S376] This region rotated partly into view at the northeast limb late on March 24. The region is bright and could produce further M class flares, a major flare is possible. Location at midnight: N15E83. Flares: C1.5 at 18:51, C7.4 at 20:18 and M1.5 at 23:32 UTC. This region was the source of an M2.4 flare at 04:39 on March 25.
March 22-24: No partly or fully earth directed CMEs observed in limited LASCO data.
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 recurrent coronal hole (CH87) in the northern hemisphere will likely rotate into geoeffective positions on March 25-26.
Processed SOHO/EIT 284 image at 00:12 UTC on March 18. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on March 25-26 and most of March 27. A high speed stream from coronal hole CH87 could arrive on March 27 or 28 and cause unsettled to minor storm conditions.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is fair to good. Propagation along long distance north-south paths is poor to fair. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant stations tonight: Radio Vibración (Venezuela) and WLAM Lewiston ME. Stations from the easternmost parts of North America were heard on many frequencies throughout the MW band].
|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.
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 EAO
classification was DSO
at midnight, area 0080
location was S04E75
|Total spot count:||59||68|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2003.09||112.2||48.7||(58.9 predicted, -1.1)|
|2003.10||151.7||65.5||(56.2 predicted, -2.7)|
|2003.11||140.8||67.3||(53.5 predicted, -2.7)|
|2003.12||114.9||46.5||(50.9 predicted, -2.6)|
|2004.01||114.1||37.2||(46.7 predicted, -4.2)|
|2004.02||107.0||46.0||(42.1 predicted, -4.6)|
|2004.03||107.9 (1)||53.0 (2)||(39.7 predicted, -2.4)|
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.