Solar Terrestrial Activity Report

Last major update issued on June 9, 2005 at 04:50 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update June 4, 2005)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update June 4, 2005)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update June 4, 2005)]
[Historical solar and geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports (last update June 4, 2005)]

Recent activity

The geomagnetic field was quiet on June 8. Solar wind speed ranged between 379 and 469 km/sec.

Solar flux measured at 20h UTC on 2.8 GHz was 115.7. The planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 5.6).
Three hour interval K indices: 22121211 (planetary), 22112001 (Boulder).

The background x-ray flux is at the class B2 level.

At midnight there were 4 spotted regions on the visible solar disk. The solar flare activity level was low. A total of 3 C class events was recorded during the day.

Region 10772 decayed further and lost about half of the penumbral area.
Region 10773 was quiet and stable.
Region 10775 developed as negative polarity flux emerged near the main (positive polarity) penumbra. A magnetic delta structure formed in a new penumbra just to the east of the largest spot. An M class flare is possible.
Region 10776 developed quickly in the leading spot section while some decay was observed in the intermediate spot section. A major flare is possible, although at this time negative and positive polarity spots are not that closely spaced. Flares: C1.2 at 01:32, C1.1 at 03:17, C2.4 at 06:25 and C1.7 at 06:40 UTC.

Coronal mass ejections (CMEs)

June 6-7: No obvious fully or partly Earth directed CMEs were observed in LASCO images.
June 8: At least a partial halo CME was observed in LASCO C3 images during the late afternoon and early evening. The ejected material was first observed over the southwest limb and was likely related to a filament eruption to the north of region 10772.

Coronal holes

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

No obvious coronal holes are currently near Earth facing positions.

Processed SOHO/EIT 284 image at 01:06 UTC on June 6. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to unsettled on June 9-10. The CME observed on June 8 could reach Earth late on June 11 or early on June 12 and cause unsettled to active conditions.

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. When the high speed stream has arrived the color changes to green.
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.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is very poor. Propagation along long distance north-south paths is fair to good. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay, however, Radio Rafaela (Argentina) at times had an amazingly clear signal, particularly after 03h UTC. On 1510 kHz Radio Rincón (Uruguay) and Radio Champaquí (Argentina) had some of the best signals I've heard them with so far. There were stations from mainly Argentina on lots of other frequencies throughout the MW band.

Active solar regions (Recent map)

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. SEC active region numbers in the table below and in the active region map above are the historic SEC/USAF numbers.

Monthly solar cycle data

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 analysis, and partly on data from some of these solar data sources. All time references are to the UTC day. Comments and suggestions are always welcome.