Last major update issued on May 30, 2010 at 04:55 UTC.
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The geomagnetic field was unsettled to minor storm on May 29. Solar wind speed ranged between 322 and 401 km/s. The high speed stream associated with CH406 appears to have arrived early on May 30.
Solar flux measured at 20h UTC on 2.8 GHz was 73.7. The planetary A index was 33 (STAR Ap - based on the mean of three hour interval ap indices: 32.8). Three hour interval K indices: 43555433 (planetary), 32555423 (Boulder).
The background x-ray flux is at the class A3 level.
At midnight there were 3 spotted regions on the visible solar disk.
New region 11073 emerged in the northeast quadrant on May 28 and was
numbered by NOAA/SWPC the next day.
New region 11074 emerged in the northwest quadrant on May 28 and
displayed little change on May 29.
New region 11075 emerged in the southern hemisphere near the central
meridian.
May 26-28: No obvious Earth directed CMEs were observed in LASCO or STEREO images.
Coronal hole history (since late October 2002)
Compare today's report to the situation one solar rotation ago:
28 days ago
27 days ago
26 days ago
A recurrent coronal hole (CH406) in the northern hemisphere was in an Earth facing position on May 28. CH406 has diminished over the last few days and could disappear soon.
Processed SOHO/EIT 195 image at 00:00 UTC on May 30. The darkest areas on the solar disk are likely coronal holes.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is very poor. Propagation on long distance northeast-southwest paths is poor to fair.
The geomagnetic field is expected to be quiet to minor storm on May 30-31 due to a high speed stream from CH406. Quiet conditions are likely on June 1-2.
| 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) Effects from a CME are likely to be observed at 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.
Compare to the previous day's image
Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC. 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 SWPC or where SWPC has observed no spots. SWPC active region numbers in the table below and in the active region map above are the historic SWPC/USAF numbers.
| Active region | Date numbered | SWPC spot count |
STAR spot count |
Location at midnight | Area | SWPC Classification |
Comment |
|---|---|---|---|---|---|---|---|
| S768 | 2010.05.25 | N18W46 | plage | ||||
| S769 | 2010.05.26 | N15W42 | plage | ||||
| 11074 | 2010.05.29 | 5 | 2 | N19W57 | 0010 | BXO | formerly region S770 classification was AXX at midnight |
| 11073 | 2010.05.29 | 3 | 3 | N13E35 | 0020 | BXO | formerly region S771 |
| 11075 | 2010.05.29 | 5 | 5 | S20W02 | 0020 | BXO | classification was CSO at midnight |
| Total spot count: | 13 | 10 | |||||
| SSN: | 43 | 40 | |||||
| Month | Average measured solar flux | International sunspot number (SIDC) | Smoothed sunspot number | Average ap (3) |
|---|---|---|---|---|
| 2000.04 | 184.2 | 125.5 | 120.8 cycle 23 sunspot max. |
|
| 2000.07 | 202.3 | 170.1 | 119.8 | |
| 2001.12 | 235.1 | 132.2 | 114.6 (-0.9) | |
| 2008.07 | 65.7 (SF minimum) | 0.5 | 2.8 (-0.4) | |
| 2008.12 | 69.2 | 0.8 | 1.7 (-) sunspot minimum |
3.25 |
| 2009.03 | 69.2 | 0.7 | 2.0 (+0.1) | 4.85 |
| 2009.04 | 69.7 | 1.2 | 2.2 (+0.2) | 4.52 |
| 2009.05 | 70.5 | 2.9 | 2.3 (+0.1) | 4.75 |
| 2009.06 | 68.6 | 2.6 | 2.7 (+0.4) | 5.22 |
| 2009.07 | 68.2 | 3.5 | 3.6 (+0.9) | 5.49 / 4.55 |
| 2009.08 | 67.3 | 0.0 | 4.8 (+1.2) | 5.70 / 4.89 |
| 2009.09 | 70.5 | 4.2 | 6.1 (+1.3) | 3.88 / 3.61 |
| 2009.10 | 72.6 | 4.6 | 7.0 (+0.9) | 3.66 / 3.56 |
| 2009.11 | 73.6 | 4.2 | (7.7 predicted, +0.7) | 2.45 / 2.63 |
| 2009.12 | 76.7 | 10.6 | (8.9 predicted, +1.2) | 1.41 / 1.92 |
| 2010.01 | 81.1 | 13.1 | (10.2 predicted, +1.3) | 2.93 / 3.07 |
| 2010.02 | 84.7 | 18.6 | (11.8 predicted, +1.6) | 4.15 / 4.61 |
| 2010.03 | 83.4 | 15.4 | (13.7 predicted, +1.9) | 4.58 / 4.65 |
| 2010.04 | 75.9 | 7.9 | (15.3 predicted, +1.8) | 10.22 / 10.24 |
| 2010.05 | 73.9 (1) | 17.0 (2) | (16.6 predicted, +1.3) | (8.63) |
1) Running average based on the
daily 20:00 UTC observed solar flux
value at 2800 MHz.
2) Current impact on the monthly SSN based on the Boulder (NOAA/SWPC) sunspot number
(accumulated daily sunspots / month days). The official international sunspot number is typically
30-50% lower.
3) Running average based on the
daily SWPC ap indices. Values in red are based on
the
official NGDC ap indices.
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.