Last major update issued on June 2, 2013 at 06:25 UTC.
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The geomagnetic field was unsettled to severe storm on June 1. Solar wind speed at SOHO ranged between 369 and 803 km/s. The initial phase of the disturbance which started on May 31 is consistent with the arrival of a corotating interactive region ahead of a strong coronal high speed stream. The high speed stream became the dominant solar wind source during the first half of June 1 and the associated disturbance was much stronger than forecast.
Solar flux measured at 20h UTC on 2.8 GHz was 105.8 (decreasing 31.3 over the last solar rotation). The Potsdam WDC planetary A index was 52 (STAR Ap - based on the mean of three hour interval ap indices: 51.6). Three hour interval K indices: 57655333 (planetary), 55655433 (Boulder).
The background x-ray flux was at the class B3 level.
At midnight UTC the visible solar disk had 9 spotted active regions (in 2K resolution SDO images).
Region 11757 [S07W25] decayed slowly and quietly.
Region 11758 [S14W03] developed slowly in the north and lost most of the
spots in the southern part of the leading polarity area. SWPC chose to split the
northern spots into AR 11763.
Region 11760 [N13E26] displayed slow growth in the leading polarity area
and decay in the trailing polarity.
New region 11762 [S28W07] emerged very quickly and could produce C flares
and maybe a minor M class flare.
Spotted regions not numbered by SWPC:
S2449 [N12W04] reemerged with penumbra spots.
S2451 [N21E09] was quiet and stable.
S2453 [N20W28] reemerged with penumbra spots.
New region S2455 [N27W58] emerged with a penumbra spot.
New region S2456 [N13E26] emerged with penumbra spots.
May 30, June 1: No obviously Earth directed CMEs were observed in LASCO and
STEREO imagery.
May 31: Several CMEs were observed during the day, none of them with
obvious Earth directed components. A large filament eruption across the central
meridian in the northern hemisphere began near noon and lasted into the evening.
The associated CME was directed northwards.
Coronal hole history (since October
2002)
Compare today's report to the situation one solar rotation ago:
28 days ago
27 days ago
26 days ago
A recurrent trans equatorial coronal hole (CH571) was in an Earth facing position on May 29-30. A coronal hole (CH572) in the southern hemisphere will likely rotate into an Earth facing position on June 4-5.
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 fair to good.
The geomagnetic field is expected to be quiet to active on June 2-3 due to effects associated with CH571. Quiet conditions are likely on June 4-6 becoming quiet to unsettled on June 7-8 due to effects from CH572.
| Coronal holes (1) | Coronal mass ejection (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 2K resolution) Compare to the previous day's image. 0.5k image
When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue 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 magnetic polarity overlay |
Comment | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| SWPC | STAR SDO | SWPC | STAR | Current | Previous | ||||||
| 2K | 1K | ||||||||||
| 11755 | 2013.05.20 2013.05.21 |
N12W87 |
 |
plage | |||||||
| 11757 | 2013.05.24 2013.05.25 |
1 | 5 | 1 | S08W26 | 0020 | HRX | HRX |
 |
 |
|
| 11758 | 2013.05.26 | 13 | 4 | S21W03 | 0030 | CRO |
 |
 |
location: S14W03 | ||
| 11759 | 2013.05.26 2013.05.27 |
S07W06 | plage | ||||||||
| S2446 | 2013.05.27 | S18W30 |
 |
plage | |||||||
| 11761 | 2013.05.28 2013.05.29 |
S17E10 |
 |
plage | |||||||
| S2449 | 2013.05.28 | 2 | N12W04 | AXX |
 |
||||||
| 11760 | 2013.05.29 | 5 | 10 | 3 | N12E26 | 0020 | CSO | CRO |
 |
 |
|
| S2451 | 2013.05.29 | 2 | N21E09 | 0005 | AXX |
 |
 |
||||
| S2452 | 2013.05.29 | N20W02 | plage | ||||||||
| S2453 | 2013.05.29 | 2 | N20W28 | AXX |
 |
||||||
| S2454 | 2013.05.30 | N13W56 |
 |
plage | |||||||
| 11762 | 2013.06.01 | 10 | 22 | 8 | S30W08 | 0070 | DAO | DAI |
 |
area: 0300 location: S28W07 |
|
| 11763 | 2013.06.01 | 4 | S15W02 | 0020 | CRO | see AR 11758 | |||||
| S2455 | 2013.06.01 | 1 | N27W58 | 0003 | AXX |
 |
|||||
| S2456 | 2013.06.01 | 3 | N32E09 | 0005 | AXX |
 |
|||||
| Total spot count: | 20 | 60 | 16 | ||||||||
| Sunspot number: | 60 | 150 | 56 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 36 | 74 | 30 | (Sum of total spot count + classification weighting for each AR. Classification weighting: X=0, R=3, A/S=5, H/K=10) | |||||||
| Relative sunspot number (Wolf number): | 36 | 53 | 31 | k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for STAR SDO 2K, k = 0.55 for STAR SDO 1K | |||||||
| Month | Average measured solar flux | International sunspot number (SIDC) | Smoothed sunspot number | Average ap (3) |
|---|---|---|---|---|
| 2011.11 | 153.5 (cycle max) | 96.7 (cycle max) | 61.1 (+1.2) | 5.55 |
| 2012.02 | 106.5 | 32.9 | 66.9 (+1.4) possible cycle 24 max |
8.81 |
| 2012.03 | 114.7 | 64.3 | 66.8 (-0.1) | 16.08 |
| 2012.04 | 113.0 | 55.2 | 64.6 (-2.2) | 10.10 |
| 2012.05 | 121.5 | 69.0 | 61.7 (-2.9) | 7.06 |
| 2012.06 | 119.6 | 64.5 | 58.9 (-2.8) | 10.08 |
| 2012.07 | 133.9 | 66.5 | 57.7 (-1.2) | 13.90 |
| 2012.08 | 115.4 | 63.0 | 58.1 (+0.4) | 7.96 |
| 2012.09 | 122.9 | 61.4 | 58.1 (-0.0) | 8.07 |
| 2012.10 | 123.3 | 53.3 | 58.6 (+0.5) | 9.97 |
| 2012.11 | 121.3 | 61.8 | 59.7 (+1.1) | 7.08 |
| 2012.12 | 108.6 | 40.8 | (59.5 projected, -0.2) | 3.44 |
| 2013.01 | 127.1 | 62.9 | (59.1 projected, -0.4) | 4.69 |
| 2013.02 | 104.3 | 38.0 | (59.3 projected, +0.2) | 6.11 |
| 2013.03 | 111.3 | 57.9 | (58.9 projected, -0.4) | 10.56 |
| 2013.04 | 124.8 | 72.4 | (58.6 projected, -0.3) | 5.40 |
| 2013.05 | 131.4 | 78.7 | (58.7 projected, +0.1) | 9.04 |
| 2013.06 | 105.8 (1) | 1.9 (2A) / 60.0 (2B) / 74.7 (2C) | (59.0 projected, +0.3) | 51.6 |
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)
Boulder SN current month
average to date. 2C) STAR SDO 1K Wolf number 30 day average.
3) Running average based on the quicklook and definitive Potsdam WDC ap indices.
Values in red are based on the definitive
international Potsdam
WDC
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.
