Last update issued on July 31, 2003 at 04:30 UTC.
[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update July 2, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update July 2, 2003)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update July 2, 2003)]
[Historical solar and geomagnetic data charts 1954-2003 (last update July 23, 2003)]
[Archived reports (last update July 21, 2003)]
The geomagnetic field was active to minor storm on July 30. Solar wind speed ranged between 701 and 980 km/sec under the influence of a high speed stream from coronal hole CH49.
Solar flux measured at 20h UTC on 2.8 GHz was 98.7. The planetary A
index was 29 (STAR Ap - based on the mean of three hour interval ap indices: 29.6).
Three hour interval K indices: 44554444 (planetary), 45543343 (Boulder).
The background x-ray flux is at the class B1 level.
At midnight there were 3 spotted regions on the visible disk. Solar flare activity was moderate. A total of 1 C and 1 M class events was recorded during the day.
Region 10420 was quiet and stable.
Region 10421 did not change much and was quiet.
Region 10422 decayed fairly quickly after the M flare and has only a minor chance of producing another M flare. Flares: C2.2 at 02:20 and M2.5/1B at 04:10 UTC.
July 28-30: No potentially 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 25 days ago
A large coronal hole (CH49) in the southern hemisphere - an extension of the southern polar coronal hole - was in a geoeffective position on July 24-29. A coronal hole (CH50) in the northern hemisphere will likely be in a geoeffective position on August 4-5.
Processed GOES SXI coronal structure image at 23:53 UTC on July 30. Base SXI image courtesy of NOAA/SEC. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to minor storm until August 1 due to a high speed stream from coronal hole CH49, quiet to unsettled is likely on August 2-6. A high speed stream from coronal hole CH50 will likely cause unsettled to active conditions on August 7-8.
Long distance low frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is useless and will likely remain useless to very poor until August 2. Propagation along north-south paths is fair and expected to remain fair until August 2. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay. A post local sunrise opening brought Uruguay on 610 kHz and Argentina on 590 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 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.
|Solar region||Date numbered||SEC
|Location at midnight||Area||Classification||Comment|
|Total spot count:||23||21|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2003.01||144.0||79.7||(79.7 predicted, -2.3)|
|2003.02||124.5||46.0||(74.7 predicted, -5.0)|
|2003.03||131.4||61.1||(69.0 predicted, -5.7)|
|2003.04||126.4||60.0||(64.1 predicted, -4.9)|
|2003.05||115.7||55.2||(59.2 predicted, -4.9)|
|2003.06||129.3||77.4||(55.2 predicted, -4.0)|
|2003.07||128.5 (1)||130.3 (2)||(51.6 predicted, -3.6)|
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 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.