Last major update issued on October 28, 2013 at 05:15 UTC.
[Solar and geomagnetic data - last month (updated
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update October 1, 2013)] [Cycle 24 progress (last update October 1, 2013) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update October 1, 2013)]
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[POES auroral activity level since October
2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated October 10, 2013]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]
The geomagnetic field was very quiet on October 27. Solar wind speed at SOHO ranged between 270 and 313 km/s.
Solar flux measured at 20h UTC on 2.8 GHz was 166.9 (increasing 62.0 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 116.5. The Potsdam WDC planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 1.9). Three hour interval K indices: 00101010 (planetary), 00102221 (Boulder).
The background x-ray flux was at the class C1 level.
At the time of counting spots (see image time) spots were observed in 10 active regions in 2K resolution (SN: 237) and 8 active regions in 1K resolution (SN: 144) SDO images on the visible solar disk.
Region 11875 [N06W66] developed with the
leader spot increasing its area significantly, a magnetic delta structure
developed in the northern part of the large penumbra. The region became more
unstable and was the most active on the solar disk during the day. The activity
continued into the early hours of October 28 with a major X1.0 flare at 02:03 (with
an associated partial halo CME) and a major M5.1 flare at 04:41 UTC. Further
major flares are possible.
C5+ flares: M3.5/1F at 12:48, C9.1/1F at 17:53 UTC. CMEs
were observed off the west limbs after these events.
Region 11877 [S12W42] was mostly quiet and stable.
Region 11879 [S12W28] regained trailing polarity umbrae and was quiet.
Region 11881 [S23W07] lost the trailing spots.
Region 11882 [S10E35] lost one of the magnetic delta structures, however, the region is developing and could produce major flares.
Region 11883 [N02E61] was quiet and stable.
Region 11884 [S15E67] shares the negative polarity area with AR 11885 and will be regarded as one region. M flares are possible.
Spotted regions not numbered by SWPC:
New region S2784 [S17E23] emerged with a few spots.
New region S2785 [N10W80] is an emerging flux region which had a penumbra spot by the end of the day.
New region S2786 [N07E05] emerged with a penumbra spot.
October 25: A faint asymmetric halo CME was observed after the X1.7 event
at 08h while a significantly larger full halo asymmetric CME was observed after
the X2.1 flare near 15h. The latter CME will likely reach Earth on October 27.
October 26: An asymmetric halo CME was observed after the M1.8 LDE near 11h. Due to many other CMEs it is difficult to determine if this one was full or partial halo. The CME could reach Earth on October 29.
October 27: The CMEs originating in AR 11875 does not appear to be Earth directed.
October 28: A partial halo CME was observed in LASCO imagery after the X1 flare early in the day. The CME could reach Earth on October 30 or 31.
Coronal hole history (since October
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.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is fair to good. Propagation on long distance northeast-southwest paths is poor to fair.
The geomagnetic field is expected to be quiet to minor storm on October 28-30 due to CME effects.
|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
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
|Spot count||Location at midnight||Area||Classification||SDO / HMI 4K continuum
image with magnetic polarity overlay
|1||N13W90||0010||HRX||rotated out of view|
|11885||2013.10.26||1||S18E63||0130||HSX||part of AR 11884|
|Total spot count:||116||137||64|
|Sunspot number:||206||237||144||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||169||188||115||(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):||124||83||79||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
|2011.11||153.5 (cycle peak)||96.7 (cycle peak)||61.1 (+1.2)||5.55|
likely cycle 24 max
|2013.04||124.8||72.4||(56.2 projected, -1.3)||5.40|
|2013.05||131.4||78.7||(55.8 projected, -0.4)||9.73|
|2013.06||110.1||52.5||(56.0 projected, +0.2)||12.60|
|2013.07||115.5||57.0||(56.1 projected, +0.1)||9.47|
|2013.08||114.6||66.0||(55.9 projected, -0.2)||8.27|
|2013.09||102.6||36.9||(55.4 projected, -0.5)||5.23|
|2013.10||129.5 (1)||108.3 (2A) / 124.3 (2B) / 71.8 (2C)||(53.9 projected, -1.5)||(7.90)|
1) Running average based on the daily 20:00 UTC observed solar flux value at
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 the 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.