Last update issued on July 22, 2003 at 04:20 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 April 13, 2003)]
[Archived reports (last update July 21, 2003)]
The geomagnetic field was quiet to active on July 21. Solar wind speed ranged between 400 and 668.
Solar flux measured at 20h UTC on 2.8 GHz was 155.6. The planetary A
index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 13.0).
Three hour interval K indices: 44212232 (planetary), 44123231 (Boulder).
The background x-ray flux is at the class B9 level.
At midnight there were 11 spotted regions on the visible disk. Solar flare activity was low. A total of 16 C class events was recorded during the day.
Region 10405 decayed further and will rotate out of view today.
Region 10409 decayed quickly and was mostly quiet. Flare: C2.0 at 22:35 UTC.
Region 10410 decayed early in the day as the main positive and negative polarity areas became better separated. Penumbral area and spots disappeared from the central part of the region, as did the magnetic delta structure. The region could still produce an M class flare. Flares: C3.2 at 00:35, C1.2 at 01:12, C1.3 at 01:55, C3.3 at 02:28, C1.4 at 03:28, C2-3 at 03:47, C1.7 at 07:27 and C1.3 at 14:17 UTC.
Region 10411 was quiet and stable.
Region 10412 decayed slowly and quietly. Flare: C1.7 at 07:39 UTC.
Region 10413 decayed and had a single tiny spot at the end of the day.
Region 10414 was quiet and stable.
Region 10415 decayed slowly and quietly.
Region 10416 decayed slowly and quietly.
Region 10417 developed further and could produce a minor M class flare. Flares: C1.8 at 00:08, C1.5 at 01:24, C1.3 at 17:09, C1.1 at 20:03 and C2.8 (flare started at 23:56 on July 21 and peaked on July 22) at 00:02 UTC.
Region 10418 was quiet and stable.
An active region behind just behind the northeast limb is capable of C class flare production. A C1.5 flare was recorded at 21:15 UTC.
July 19: A faint partial halo CME was observed in LASCO C3 images early in the day following an event in region 10412. The CME was observed over the west limbs and some of the east limbs.
July 20-21: 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 26 days ago
A large coronal hole (CH49) in the southern hemisphere will likely be in a geoeffective position on July 24-27, a thin western extension could be in a geoeffective position on July 22.
Processed GOES SXI coronal structure image at 22:26 UTC on July 21. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on July 21-24. There is a minor chance that a CME observed on July 19 could reach Earth on July 22 and cause unsettled to active conditions.
Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very poor. Propagation along north-south paths is poor. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay with Radio Vibración (Venezuela) noted at times.]
|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|
classification was CAO
area was 0900
area was 0060
area was 0040
classification was DAC
at midnight, area 0240
|Total spot count:||109||134|
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||134.1 (1)||102.2 (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.