Last update issued on May 23, 2003 at 03:20 UTC.
[Solar and geomagnetic data - last 4 weeks (updated daily)]
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[Solar cycles 21-23 (last update May 1, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update May 1, 2003)]
[Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update May 1, 2003)]
[Historical solar and geomagnetic data charts 1954-2003 (last update April 13, 2003)]
[Archived reports (last update May 19, 2003)]
The geomagnetic field was quiet to minor storm on May 22. Solar wind speed ranged between 451 and 528 km/sec under the influence of a high speed stream from coronal hole CH40.
Solar flux measured at 20h UTC on 2.8 GHz was 118.4. The planetary A
index was 25 (STAR Ap - based on the mean of three hour interval ap indices: 26.0).
Three hour interval K indices: 55434432 (planetary), 55424433 (Boulder).
The background x-ray flux is at the class B3 level.
At midnight there were 8 spotted regions on the visible disk. Solar flare activity was low. A total of 4 C class events was recorded during the day.
Region 10362 decayed slowly but still has mixed polarities in the trailing spot section. Flare:
C1.1 at 06:16, C4.9 at 07:03, C1.2 at 17:32 and C1.1 at 21:14 UTC.
Region 10364 decayed and had only a single small spot left at the end of the day. The region will likely become spotless before rotating over the southwest limb.
Region 10365 decayed and lost penumbral area in the northern part.
New region 10366 emerged early in the day at the northeast limb.
New region 10367 rotated into view at the southeast limb on May 21 and was numbered by SEC the next day.
New region 10368 rotated into view at a high latitude at the southeast limb early in the day.
Spotted regions not numbered by SEC/NOAA:
[S167] A new region rotated into view at the northeast limb on May 22. Location at midnight: N16E67.
[S168] A new region emerged slowly in the northeast quadrant late on May 22. Location at midnight: N12E19.
May 20-22: 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 recurrent trans equatorial coronal hole (CH40) was in a geoeffective position on May 18-21. A recurrent coronal hole (CH41) in the southern hemisphere will rotate into a geoeffective position on May 24.
Processed SOHO EIT 284 image at 19:06 UTC on May 22. Any black areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be unsettled to active on May 23-24 due to a high speed stream from coronal hole CH40 and quiet to active on May 25.
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 25. Propagation along north-south paths is poor. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: none, weak signals noted from Radio Cristal del Uruguay and Radio Vibración (Venezuela).]
|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 HSX
at midnight, area 0020
classification was HSX
at midnight, only
negative polarity spots
classification was BXO
formerly region S166
classification was HAX
|Total spot count:||40||31|
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||113.3 (1)||66.2 (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 30-50% 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.