Solar Terrestrial Activity Report

Last major update issued on July 14, 2005 at 06:15 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, 2005)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update July 2, 2005)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update July 2, 2005)]
[Historical solar and geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports (last update July 2, 2005)]

Recent activity

The geomagnetic field was unsettled to minor storm on July 13. Solar wind speed ranged between 452 and 665 (all day average 564) km/sec.

Solar flux measured at 20h UTC on 2.8 GHz was 91.7. The planetary A index was 30 (STAR Ap - based on the mean of three hour interval ap indices: 30.5).
Three hour interval K indices: 34555434 (planetary), 34445333 (Boulder).

The background x-ray flux is at the class C1 level.

At midnight there were 5 spotted regions on the visible solar disk. The solar flare activity level was high. A total of 8 C and 4 M class events was recorded during the day.

Region 10786 developed further and rotated partly out of view at the northeast limb as a very complex region. Further M class flares are very likely, and a major proton flare is a possibility. Flares: C4.2 at 01:38, long duration M1.1 peaking at 03:16, C4.7 at 06:38, C2.1 at 07:39, C2.7 at 08:22, C3.9 at 09:02, C1.6 at 10:14, M3.2 at 12:19, major long duration M5.0 peaking at 14:49 (associated with a large full halo CME and a small above 10 MeV proton event), M1.2/1F at 19:09, C2.7 at 20:55, M1.2 at 21:54 and C1.8 at 22:53 UTC.
Region 10788 was quiet and stable.
Region 10789 decayed slowly and lost penumbra on the leader spots.
New region 10790 emerged in the southwest quadrant on July 12 and was numbered by SEC the next day. Slow decay was observed on July 13.

Spotted regions not numbered by NOAA/SEC:
[S570] This region emerged in the southwest quadrant on July 13 just west of region 10790. Location at midnight: S12W41.

Coronal mass ejections (CMEs)

July 11: No obvious fully or partly Earth directed CMEs were observed during the day.
July 12: The M1 long duration event in region 10786 during the afternoon was associated with a faint full halo CME. While parts of this CME were visible over the northwest limb at 17:42 UTC, it wasn't until 3 hours later that this developed into a full halo CME when much fainter extensions became visible over the east limb in LASCO C3 images.
July 13: A large, wide and fast full halo CME was observed during the afternoon and early evening in LASCO C3 images after the M5 long duration event in region 10786.

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

A recurrent trans equatorial coronal hole (CH175) will rotate into an Earth facing position on July 17-18.

Processed SOHO/EIT 284 image at 01:06 UTC on July 14. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to active on July 14. CMEs could reach Earth during the latter half of July 15 and cause unsettled to minor storm conditions that day and on July 16. Quiet to unsettled is likely on July 17.

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 poor to fair. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay. Several stations from Argentina, Uruguay and Brazil were audible on other frequencies.

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% lower.

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.