Last major update issued on August 3, 2010 at 06:00 UTC. Minor update posted at 17:25 UTC.
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The geomagnetic field was quiet on August 2. Solar wind speed ranged between 380 and 514 km/s.
Solar flux measured at 20h UTC on 2.8 GHz was 79.1. The planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 5.4). Three hour interval K indices: 12111212 (planetary), 12211211 (Boulder).
The background x-ray flux is at the class B1 level.
At 20h UTC the visible solar disk had 2 spotted regions.
Region 11092 was mostly unchanged and remains capable of producing occasional C flares.
Spotted regions not numbered by NOAA/SWPC:
[S795] This region emerged in the northern hemisphere near the
central meridian on August 2. Location at midnight: N25W06
Minor update posted at 17:25 UTC: A moderately strong solar wind shock was observed at ACE near 17h UTC. Solar wind velocity has increased to near 550 km/s and a minor increase in the above 10 MeV proton flux has been observed. This is the arrival of the CME observed on August 1.
July 31 and August 2: No obviously Earth directed CMEs were seen in LASCO or STEREO
images.
August 1: A full halo CME associated with a C3 long duration event in
region 11092 could reach Earth sometime between the afternoon on August 3 and
noon on August 4.
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
No obvious coronal holes are currently in or near Earth facing positions.
Image courtesy of SDO (NASA) and the AIA consortium. Annotations are my own. 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 poor to fair. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet most of August 3. The arrival the CME observed on August 1 could cause unsettled to major storm conditions from late on August 3 and on August 4-5.
| 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 | Spot count | Location at midnight | Area | Classification | SDO (NASA) / AIA 4500 image |
Comment | |||
|---|---|---|---|---|---|---|---|---|---|---|
| SWPC | STAR | SWPC | STAR | Current | Previous | |||||
| 11090 | 2010.07.24 | N22W62 | plage | |||||||
| 11092 | 2010.07.28 | 7 | 8 | N16E10 | 0280 | CHO | CHO |
 |
 |
|
| S794 | 2010.07.30 | S20W53 | plage | |||||||
| S795 | 2010.08.02 | 1 | N25W06 | 0010 | AXX |
 |
||||
| Total spot count: | 7 | 9 | ||||||||
| SSN: | 17 | 29 | ||||||||
| 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 |
| 2009.06 | 68.6 | 2.9 | 2.7 (+0.4) | 5.22 |
| 2009.07 | 68.2 | 3.2 | 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 | 4.3 | 6.2 (+1.4) | 3.88 / 3.61 |
| 2009.10 | 72.6 | 4.8 | 7.1 (+0.9) | 3.66 / 3.56 |
| 2009.11 | 73.6 | 4.1 | 7.6 (+0.5) | 2.45 / 2.63 |
| 2009.12 | 76.7 | 10.8 | 8.3 (+0.7) | 1.41 / 1.92 |
| 2010.01 | 81.1 | 13.2 | 9.3 (+1.0) | 2.93 / 3.07 |
| 2010.02 | 84.7 | 18.8 | (10.6 predicted, +1.3) | 4.15 / 4.61 |
| 2010.03 | 83.4 | 15.4 | (12.3 predicted, +1.7) | 4.58 / 4.65 |
| 2010.04 | 75.9 | 7.9 | (13.9 predicted, +1.6) | 10.22 / 10.24 |
| 2010.05 | 73.8 | 8.8 | (15.3 predicted, +1.4) | 9.18 / 8.15 |
| 2010.06 | 72.5 | 13.5 | (16.7 predicted, +1.4) | 8.17 / 6.85 |
| 2010.07 | 79.8 | 16.1 | (18.3 predicted, +1.6) | 6.31 |
| 2010.08 | 79.4 (1) | 1.0 (2) | (19.5 predicted, +1.2) | (4.63) |
1) Running average based on the
daily 20:00 UTC observed solar flux
value at 2800 MHz.
2) Current impact on the monthly sunspot number 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.