Last update December 25, 2002 at 04:30 UTC.
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The geomagnetic field was quiet to active on December 24. Solar wind speed ranged between 468 and 574 km/sec. A weak solar wind shock was observed at ACE at 13:18 UTC. Solar wind speed increased abruptly from 470 to 520 km/sec and the interplanetary magnetic field was at times moderately southwards after the shock.
Solar flare activity was low. Solar flux was 147.3, the planetary A
index was 18 (STAR Ap - based on the mean of three hour ap indices: 18.6).
Three hour interval K indices: 32334433 (planetary), 32334433 (Boulder).
The background x-ray flux is at the class B7 level.
At midnight there were 6 spotted regions on the visible disk, 1 of which has not yet been numbered. A total of 8 C class events were recorded during the day. C2.7 flares at 18:21 and 23:36 were optically uncorrelated.
Region 10223 decayed and became spotless in the early morning.
Region 10224 decayed fairly quickly as the region rotated to the southwest limb. Flares: C5.8 at 05:27, C1.6 at 13:29 and C5.8 at 14:51 UTC.
Region 10229 decayed further and had only a single spot left by the end of the day.
Region 10230 decayed quickly in the trailing spot section where only two tiny spots could be observed at the end of the day.
Region 10231 decayed in the leading spot section while the main trailing spot increased its area.
Region 10233 decayed and was spotless by early afternoon.
New region 10234 rotated into view at the northeast limb early in the day.
Spotted regions not yet numbered by SEC:
[S60] A new region began to emerge in the northeast quadrant late on December 24. Location at midnight: N11E40.
December 22: A CME was observed off of the northwest limb early in the day after an M1.1 flare and an associated filament eruption in region 10223. The CME does not appear to be geoeffective.
December 23-24: 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 large and well defined trans equatorial coronal hole will be in a geoeffective position on December 24-25.
Processed SOHO EIT 284 image at 19:06 UTC on December 24. Any black areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on December 25-26. A coronal stream will likely arrive early on Dec.27 and cause unsettled to minor storm conditions. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor to very poor.
|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.
Composite image based on a SOHO/MDI continuum image and overlaid by a coronal hole image. Region numbering has been included. Compare to the previous day 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|
|10226||2002.12.13||4||S28W89||0110||EAO||rotated out of view|
classification was HSX
at midnight, area 0030
classification was CAO
|Total spot count:||39||14|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2002.06||148.7||88.3||(106.4 predicted, -2.4)|
|2002.07||173.5||99.9||(102.8 predicted, -3.6)|
|2002.08||183.6||116.4||(99.6 predicted, -3.2)|
|2002.09||175.8||109.3||(96.6 predicted, -3.0)|
|2002.10||167.0||97.5||(93.1 predicted, -3.5)|
|2002.11||168.7||95.0||(87.8 predicted, -5.3)|
|2002.12||168.1 (1)||131.3 (2)||(83.5 predicted, -4.3)|
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. Comments and suggestions are always welcome.
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