Last update issued on March 13, 2003 at 03:15 UTC.
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The geomagnetic field was quiet to unsettled on March 12. Solar wind speed ranged between 401 and 552 km/sec. A high speed stream appears to have been in progress since just after 22h UTC at ACE.
Solar flux measured at 20h UTC on 2.8 GHz was 138.0. The planetary A
index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 9.9).
Three hour interval K indices: 22223333 (planetary), 22213323 (Boulder).
The background x-ray flux is at the class B2-B3 level.
At midnight there were 3 spotted regions on the visible disk. Solar flare activity was very low.
Region 10300 decayed quickly during the latter half of the day.
Region 10306 developed slowly adding several small spots. At least C class flares are possible.
Region 10311 decayed fairly quickly. The positive and negative polarity areas are currently well separated and further decay is likely.
March 9-11: No obviously geoeffective CMEs 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 well defined, large, recurrent coronal hole (CH25) will rotate into a geoeffective position on March 11-17. This coronal hole has developed in the northwestern trans equatorial part but seems to have lost the long trans equatorial extension further east.
Processed SOHO EIT 284 image at 19:06 UTC on March 12. Any black areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be unsettled to minor storm on March 13 as a high speed coronal hole stream begins to dominate the solar wind. Unsettled to active conditions will then be likely March 14-20. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor, propagation along north-south paths is fair to good. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay.]
|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.
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 SEC/NOAA. 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.
|Solar region||Date numbered||SEC
|Location at midnight||Area||Classification||Comment|
|10296||2003.02.28||1||N12W85||0220||HHX||rotated out of view|
|10297||2003.03.01||2||S11W80||rotated out of view|
the spots belong to
10297, this region
should be deleted
classification was EKO
at midnight. STAR
spot count includes
this is a trailing
negative polarity spot
of region 10306
classification was DAO
|Total spot count:||39||25|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2002.09||175.8||109.6||(94.7 predicted, -4.0)|
|2002.10||167.0||97.5||(91.2 predicted, -3.5)|
|2002.11||168.7||95.0||(86.0 predicted, -5.2)|
|2002.12||157.2||81.6||(81.6 predicted, -4.4)|
|2003.01||144.0||79.5||(78.6 predicted, -3.0)|
|2003.02||124.5||46.2||(73.6 predicted, -5.0)|
|2003.03||145.0 (1)||57.3 (2)||(67.9 predicted, -5.7)|
1) Running average based on the daily 20:00 UT observed solar flux value at 2800
2) Unofficial, accumulated value based on the Boulder (SEC/NOAA) sunspot number. The official international sunspot number is typically 25-45% less.
This report has been prepared by Jan Alvestad. It is based partly on my own observations and interpretations, and partly on data from sources noted in solar links. All time references are to the UTC day. Comments and suggestions are always welcome.