Solar Terrestrial Activity Report

Last major update issued on November 6, 2004 at 04:45 UTC. Warning: Severe solar storm headed for Earth.

[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 very quiet to unsettled on November 5. Solar wind speed ranged between 333 and 424 km/sec, slowly decreasing all day

Solar flux measured at 20h UTC on 2.8 GHz was 141.2. The planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.0).
Three hour interval K indices: 31001110 (planetary), 20002210 (Boulder).

The background x-ray flux is at the class B7 level.

At midnight there were 4 spotted regions on the visible solar disk. The solar flare activity level was moderate. A total of 15 C and 2 M class events was recorded during the day. A C1.6 flare at 14:28 UTC had its source in a spotless area near the southwest limb.

Spotted regions not numbered by NOAA/SEC:
[S469] This region emerged in the northwest quadrant on November 5. Location at midnight: N07W38.

Coronal mass ejections (CMEs)

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.
November 5: No obviously Earth directed CMEs observed.
November 4: Two full halo CMEs was observed during the day. The first one was after a long duration C6 event in region 10696 in the morning. This CME, if not overtaken by the larger CME observed later in the day, is likely to reach Earth either late on November 6 or early on November 7. The second CME was associated with a major long duration event in region 10696 late in the day. This was a fast, large, full halo CME, and it is likely to reach Earth either late on November 6 or during the first half of November 7.
November 3: A halo CME was observed after an M1 event in region 10696 early in the day. While this CME was not aimed directly at Earth, a sideways glancing impact is possible late on November 6. A large, fast, full halo CME was observed after an M5 event in region 10696 during the afternoon. Again, this CME was not aimed directly at Earth. However, much more mass was observed over the west limbs compared to the event earlier in the day. This CME is likely to impact Earth's magnetosphere near noon on November 6 and cause active to minor storm conditions.

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

An extension (CH123) of the northern polar coronal hole was in a geoeffective position on November 3. 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.

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

Forecast

The geomagnetic field is expected to be quiet initially on November 6. At least 2 CMEs could impact the magnetosphere during the day and cause active to minor storm conditions. Major storming is possible late in the day. Minor to very severe storming is possible late on November 7 and on November 8. While several coronal hole streams are headed for Earth, none of them are likely to be noticed in the presence of the much more powerful CMEs.

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 fair to occasionally fair to good. Propagation along long distance north-south paths is poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant stations tonight: WLAM Lewiston ME, WWNN Boca Raton FL and Radio Vibración (Venezuela). Lots of stations from the easternmost parts of North America were noted on other frequencies, even with some daytimers being audible before 22h UTC.

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.