Solar Terrestrial Activity Report

Last major update issued on November 19, 2004 at 04:10 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update November 4, 2004)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update November 4, 2004)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update November 4, 2004)]
[Historical solar and geomagnetic data charts 1954-2004 (last update November 8, 2004)]
[Archived reports (last update November 12, 2004)]

Recent activity

The geomagnetic field was inactive to very quiet on November 18. Solar wind speed ranged between 322 and 377 km/sec.

Solar flux measured at 20h UTC on 2.8 GHz was 104.0. The planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 2.6).
Three hour interval K indices: 00011111 (planetary), 10011112 (Boulder).

The background x-ray flux is at the class B8 level.

At midnight there were 3 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. All events occurred in region 10700 which has rotated over the northwest limb. Activity in this region has increased strongly over the last few hours and an M class flare from behind the limb is possible. Flares: C3.6 at 14:56, C1.9 at 19:48 and C1.9 at 23:05 UTC.

Coronal mass ejections (CMEs)

November 16-18: No obviously Earth directed CMEs observed.

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

Recurrent coronal hole CH127 in the northern hemisphere in a geoeffective position on November 15-18. Recurrent coronal hole CH128 in the southern hemisphere will likely rotate into a geoeffective position on November 22.

Processed SOHO/EIT 284 image at 01:06 UTC on November 19. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet initially on November 19 becoming unsettled to active later in the day when the effects from coronal hole CH127 arrive. Quiet to active is possible on November 20 becoming quiet to unsettled on November 21-23.

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 poor to very poor. Propagation along long distance north-south paths is poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay. This stations and Brazilians on 980 and 1440 kHz were the only audible stations on the antenna pointed towards west southwest. On the antenna pointed north northwest the only station with audio was Greenland on 650 kHz, actually quite a good signal. During the morning of November 18 propagation was very unusual with the only identified stations from Mexico (1570 La Poderosa, another station with Spanish was noted with a weaker signal on this frequency) and Texas (1700 KVNS Brownsville). Several interesting stations in Spanish were noted on frequencies above 1400 kHz with the best signals on 1430, 1490 (which had the second of only 2 stations in English noted on any trans Atlantic frequency as a weak signal below the other station) and 1550 kHz. It appears as if the slow reconstruction of the propagation layers increases the possibility of logging stations usually blocked by stronger signals.

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.