Last major update issued on June 2, 2011 at 05:25 UTC.
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NEW
The geomagnetic field was quiet to unsettled on June 1. Solar wind speed ranged between 448 and 616 km/s under the diminishing influence of a high speed stream from CH451.
Solar flux measured at 20h UTC on 2.8 GHz was 113.6 (increasing 8.7 over the last solar rotation). The planetary A index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 11.9). Three hour interval K indices: 31312333 (planetary), 31422312 (Boulder).
The background x-ray flux is at the class B4 level.
At midnight UTC the visible solar disk had 10 spotted regions.
Region 11225 was quiet and stable.
Region 11226 decayed slowly and still has minor polarity intermixing.
Further C flares are likely. Flares: C1.6 at
16:16, C2.9 at 16:31, C4.1/1F long duration event peaking at 17:08 UTC. The
latter event was associated with a filament eruption to the north of the region
and a CME.
Region 11227 was quiet and stable.
Region 11228 has minor polarity intermixing. Flare:
C2.6 at 02:53 UTC
Region 11229 decayed slowly and was quiet.
Region 11230 was quiet and stable.
New region 11231 rotated partly into view at the northeast limb on May 31
and was numbered the next day by NOAA/SWPC.
Spotted regions not numbered by NOAA/SWPC:
[S1043] emerged in the northeast quadrant on June 1. Location at midnight:
N09E62
[S1044] was split off from region 11227 on June 1. Location at midnight:
S19E25
[S1045] emerged with a tiny spot in the southwest quadrant on June 1.
Location at midnight: S22W13
May 30-31: No obviously Earth directed CMEs were observed in LASCO
and STEREO imagery.
June 1: An apparently Earth directed CME was observed after the C4
event in and to the north of region 11226.
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
The southernmost extension of a large coronal hole (CH452) in the northern hemisphere was in an Earth facing position on May 30-31.
The above coronal hole map is based on a new method where coronal holes are detected automatically. The method may need some fine tuning, however, it has significant advantages over detecting coronal holes manually. The main improvement is the ability to detect coronal holes at and just beyond the solar limbs. Early results using this method for SDO images over a span of several weeks indicate a good match between coronal holes observed over the visible disk and their extent and position at the east and west limbs. Note that the polar coronal holes are easily detected using the new method, the extent and intensity of both holes are consistent with other data sources.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is fair to good.
The geomagnetic field is expected to be quiet to active on June 2-3 due to effects from CH452. The CME observed on June 1 could arrive on June 4 and cause unsettled to minor storm conditions.
| 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.
(Click on image for higher resolution image) Compare to the previous day's image
When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue (blue-green) is positive.
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 detected |
Spot count | Location at midnight | Area | Classification | SDO / HMI 4K continuum image with polarity overlay |
Comment | |||
|---|---|---|---|---|---|---|---|---|---|---|
| SWPC | STAR SDO | SWPC | STAR | Current | Previous | |||||
| 11223 | 2011.05.21 2011.05.26 |
S17W64 | plage | |||||||
| S1026 | 2011.05.25 | N10W47 | plage | |||||||
| 11225 | 2011.05.25 2011.05.27 |
1 | 5 | N16W09 | 0020 | HSX | CRO |
 |
 |
location: N17W04 |
| 11224 | 2011.05.26 2011.05.27 |
N21W82 |
 |
plage | ||||||
| 11226 | 2011.05.27 | 15 | 35 | S22E14 | 0150 | CSI | CSI |
 |
 |
beta-gamma |
| S1033 | 2011.05.28 | S18W17 | plage | |||||||
| 11228 | 2011.05.28 2011.05.29 |
6 | 18 | N17E31 | 0090 | CSO | CSO |
 |
 |
beta-gamma |
| 11227 | 2011.05.28 2011.05.29 |
7 | 11 | S19E26 | 0100 | DSO | CSO |
 |
 |
location: S22E33 |
| S1037 | 2011.05.28 | N00W50 | plage | |||||||
| S1038 | 2011.05.28 | N30W45 | plage | |||||||
| 11229 | 2011.05.29 2011.05.30 |
5 | 7 | N16E10 | 0030 | BXO | CRO |
 |
 |
|
| 11230 | 2011.05.30 2011.05.31 |
2 | 6 | N19E44 | 0010 | BXO | BXO |
 |
 |
|
| 11231 | 2011.05.31 2011.06.01 |
1 | 2 | N09E68 | 0040 | HSX | CSO |
 |
 |
formerly region S1042 location: N08E73 |
| S1043 | 2011.06.01 | 6 | N09E62 | 0010 | BXO |
 |
||||
| S1044 | 2011.06.01 | 6 | S19E25 | 0030 | CSO |
 |
split off from 11227 | |||
| S1045 | 2011.06.01 | 1 | S22W13 | 0000 | AXX |
 |
||||
| Total spot count: | 37 | 97 | ||||||||
| Sunspot number: | 107 | 197 | ||||||||
| Month | Average measured solar flux | International sunspot number (SIDC) | Smoothed sunspot number | Average ap (3) |
|---|---|---|---|---|
| 2008.07 | 65.7 (SF minimum) | 0.5 | 2.8 (-0.4) | |
| 2008.12 | 69.2 | 0.8 | 1.7 (-) sunspot minimum |
3.25 |
| 2010.02 | 84.7 | 18.8 | 10.6 (+1.3) | 4.15 / 4.61 |
| 2010.03 | 83.4 | 15.4 | 12.3 (+1.7) | 4.58 / 4.65 |
| 2010.04 | 75.9 | 8.0 | 14.0 (+1.7) | 10.22 / 10.24 |
| 2010.05 | 73.8 | 8.7 | 15.5 (+1.5) | 9.18 / 8.15 |
| 2010.06 | 72.5 | 13.6 | 16.4 (+0.9) | 8.17 / 6.85 |
| 2010.07 | 79.8 | 16.1 | 16.7 (+0.3) | 6.31 / 5.15 |
| 2010.08 | 79.2 | 19.6 | 17.4 (+0.7) | 8.49 / 7.77 |
| 2010.09 | 81.1 | 25.2 | 19.6 (+2.2) | 5.33 / 5.45 |
| 2010.10 | 81.6 | 23.5 | 23.2 (+3.6) | 6.07 / 6.27 |
| 2010.11 | 82.5 | 21.5 | 26.5 (+3.3) | 4.80 / 5.50 |
| 2010.12 | 84.2 | 14.4 | (29.4 predicted, +2.9) | 3.41 / 4.35 |
| 2011.01 | 83.6 | 19.1 | (32.6 predicted, +3.2) | 4.32 / 5.51 |
| 2011.02 | 94.6 | 29.4 | (35.2 predicted, +2.6) | 5.41 / 6.44 |
| 2011.03 | 115.0 | 56.2 | (37.5 predicted, +2.3) | 7.79 |
| 2011.04 | 112.6 | 54.4 | (40.4 predicted, +2.9) | 9.71 |
| 2011.05 | 95.8 | 41.6 | (43.7 predicted, +3.3) | 9.18 |
| 2011.06 | 113.6 (1) | 3.6 (2A) / 107 (2B) | (47.4 predicted, +3.7) | (11.88) |
1) Running average based on the daily 20:00 UTC observed solar flux value at
2800 MHz.
2A) Current impact on the monthly sunspot number based on the Boulder
(NOAA/SWPC) sunspot number (accumulated daily sunspots / month days). The
official SIDC international sunspot number is typically 30-50% lower. 2B) Month
average to date.
3) Running average based on the preliminary 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 on analysis of data from whatever sources are available at the time the report is prepared. All time references are to the UTC day. Comments and suggestions are always welcome.
SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.
