Last major update issued on March 19, 2004 at 04:40 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 to unsettled on March 18. Solar wind speed ranged between 335 and 419 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 115.4. The planetary A
index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.5).
Three hour interval K indices: 33333222 (planetary), 43223323 (Boulder).
The background x-ray flux is at the class B4 level.
At midnight there were 5 spotted regions on the visible disk. Solar flare activity was moderate. A total of 8 C and 2 M class events was recorded during the day.
Region 10573 decayed slowly and quietly.
Region 10574 developed slowly with most of the leading and intermediate penumbrae gaining area. The largest penumbra, in the trailing spot section, became smaller. While there is little separation between polarities in the central section, the region is currently not quite as complex as it was one day ago. A minor M class flare is possible. Flares: M1.6/2B at 05:17, C8.0 at 06:15 and C1.2 at 09:50 UTC.
Region 10576 developed slowly and quietly.
Region 10577 was quiet and stable.
New region 10578 rotated into view at the northeast limb. This is a small, compact region which has produced numerous flares and continues to be active. M class flares are possible. Flares: C1.4 at 01:33, C3.7 at 06:05, C3.1 at 12:22, C2.7 at 14:46, C3.7 at 19:27, C1.2 at 22:11 and M1.5/1F at 22:36 UTC.
March 17-18: No partly or fully earth directed CMEs observed.
March 16: A CME was observed off of the northwest limb (first in LASCO C3 at 17:18 UTC) following a long duration event just south of region 10572. Within 3 hours faint ejecta was observed all around the disk, thus this could be a full halo CME. If it is, a weak CME impact could be observed on March 19 or 20.
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, poorly defined coronal hole (CH85) in the northern hemisphere will rotate into a geoeffective position on March 20.
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 mostly quiet to unsettled on March 19-22. A weak CME impact is possible on March 19 or 20 and could cause unsettled to active conditions.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor and slowly improving. Propagation along long distance north-south paths is fair to poor. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela). WWZN Boston on 1510 kHz had a fair signal, several of the Newfoundland stations were noted as well].
|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|
|10570||2004.03.05||2||S14W93||0120||DSO||rotated out of view|
classification was CRO
location was S04E40
location was S01E64
classification was DAC
|Total spot count:||37||47|
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||105.5 (1)||35.5 (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.