Last update issued on May 9, 2003 at 02:45 UTC.
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The geomagnetic field was unsettled to minor storm on May 8. Solar wind speed ranged between 639 and 786 km/sec under the influence of a high speed stream from coronal hole CH38.
Solar flux measured at 20h UTC on 2.8 GHz was 100.9. The planetary A
index was 30 (STAR Ap - based on the mean of three hour interval ap indices: 31.8).
Three hour interval K indices: 55454453 (planetary), 54454453 (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 low. A total of 5 C class events was recorded during the day. Region 10349 behind the southwest limb was the likely source of a C1.9 flare at 11:46 and a C2.0 flare at 16:50 UTC.
Region 10348 rotated over the southwest limb and only the easternmost trailing penumbra was visible at the end of the
day. Flares: C2.3 at 05:47, C1.2 at 08:58 and a long duration C1.1 event peaking at 13:50 UTC.
Region 10351 was quiet and stable.
Region 10353 decayed and could soon become spotless.
Region 10354 decayed slowly and could become spotless today or tomorrow.
Spotted regions not yet numbered by SEC/NOAA:
[S157] A new region rotated partly into view at the northeast limb. This region has been fairly active over the last few days and is likely to produce C flares. Location at midnight: N17E80.
May 6-8: 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 huge recurrent coronal hole (CH38) in the southern hemisphere was in a geoeffective position on May 2-9.
Processed SOHO EIT 284 image at 19:06 UTC on May 8. Any black areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be unsettled to minor storm until May 12 due to a high speed stream from coronal hole CH38. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very poor and will likely be very poor until at least May 13. Propagation along north-south paths is good and is likely to be at least fair until May 13. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay with an unusually strong signal. Even so a few stations from Brazil were noted as well. Uruguay was heard on several other frequencies, including 1420 and 1510 kHz.]
|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|
classification was HRX
|Total spot count:||3||11|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2002.11||168.7||95.5||(84.9 predicted, -5.6)|
|2002.12||157.2||80.8||(80.5 predicted, -4.4)|
|2003.01||144.0||79.5||(77.5 predicted, -3.0)|
|2003.02||124.5||46.2||(72.4 predicted, -5.1)|
|2003.03||131.4||61.5||(66.8 predicted, -5.6)|
|2003.04||126.4||60.0||(61.9 predicted, -4.9)|
|2003.05||130.4 (1)||34.4 (2)||(57.9 predicted, -4.0)|
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 (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.