Solar Terrestrial Activity Report

Last major update issued on November 8, 2004 at 02:40 UTC. Warning: Very severe geomagnetic storming in progress. Another large solar storm is in transit and could impact Earth during the latter half of November 8.

[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 August 28, 2004)]
[Archived reports (last update November 4, 2004)]

Recent activity

The geomagnetic field was quiet to severe storm on November 7. Solar wind speed ranged between 306 and 717 km/sec. A weak solar wind shock was observed at SOHO at 02:22 UTC. Solar wind speed increased abruptly from 315 to 355 km/sec. Only a mild increase in geomagnetic activity was observed. This was likely the arrival of the CME observed after the M1 event in region 10696 on November 3. The second CME arrival of the day was observed at SOHO at 10:22 UTC. Solar wind speed increased abruptly from 340 to 420 km/sec. The most likely source of this CME was the halo CME observed after the M5 event in region 10696 on November 3. Another CME may have arrived near 13:30 UTC. While there was no obvious shock ACE EPAM data and IMF hints at the possibility of a new disturbance arriving then. In that case the most likely candidate as the CME source would be the full halo CME observed late on November 4. The last CME arrival was observed at SOHO at 17:59 UTC. This was probably the arrival of the large full halo CME observed early on November 6 after a complex series of events in region 10696. This CME would then have been in transit for about 36 hours when it reached the Earth about half an hour later with the solar wind speed increasing abruptly from 450 to 690 km/sec. A proton event started immediately afterwards and has so far peaked near 460 pfu. The geomagnetic disturbance caused by this last CME arrival has been very impressive with extremely severe storming recorded by most magnetometers early on November 8. The planetary A index for the 23 to 02h UTC interval has reached the maximum attainable value: 400.

Solar flux measured at 20h UTC on 2.8 GHz was 129.6. The planetary A index was 39 (STAR Ap - based on the mean of three hour interval ap indices: 39.1).
Three hour interval K indices: 12133567 (planetary), 12132655 (Boulder).

The background x-ray flux is at the class B5 level.

At midnight there were 3 spotted regions on the visible solar disk. The solar flare activity level was high. A total of 15 C, 1 M and 1 X class events was recorded during the day.

Coronal mass ejections (CMEs)

November 7: No observations due to no new LASCO images.
November 6: A fast and large CME aimed almost directly at Earth was observed early in the day following a sequence of M class events in region 10696, the largest was an M9 event just after midnight. This CME could reach Earth during the latter half of November 7 or early on November 8. (Note that LASCO images are generally very poor in a sector covering the south pole, otherwise image quality is fairly good)
November 5: 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

A recurrent coronal hole (CH124) in the southern hemisphere was in a geoeffective position on November 4-5. Most of CH124 closed on November 5 due to the development of region 10696. Coronal hole CH125 in the southern hemisphere will likely rotate into a geoeffective position on November 8.

Processed SOHO/EIT 284 image at 19:06 UTC on November 7. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be at major to extremely severe storm levels on November 8 and the first half of November 9. Unsettled to major storm is likely for the latter half of November 9 with quiet to active likely on November 10. quiet to major storm on November 7 due to several CME impacts. A coronal hole flow could reach Earth on November 11 and cause unsettled to active conditions. Of course, another event in region 10696 could cause geomagnetic activity to become higher than stated above on November 10 and 11. With region 10696 rotating well into the western hemisphere there is an increasing chance that another major eruption will be associated with a large increase in proton levels at Earth.

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 useless. Propagation along long distance north-south paths is poor to very poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant stations tonight: none, only a very weak signal from an unidentified Brazilian station was noted. On other frequencies only a few stations from Brazil could be heard. Rádio Sociedade on 740 kHz had a fair signal, as did Rádio Uirapurú on 760 kHz. Other than that I detected weak Brazilians on 1500 and 1520 kHz. No other trans Atlantic signals could be heard.

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.