Last major update issued on October 25, 2013 at 04:40 UTC. Minor update posted at 16:15 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)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update October 1, 2013)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update October 9, 2013)]
[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 24. Solar wind speed at SOHO ranged between 300 and 386 km/s.
Solar flux measured at 20h UTC on 2.8 GHz was 160.6 (increasing 52.7 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 114.9. 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: 11010000 (planetary), 01011211 (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 12 active regions in 2K resolution (SN: 295) and 9 active regions in 1K resolution (SN: 184) SDO images on the visible solar disk.
Region 11872 [S17W49] was quiet and stable.
Region 11873 [N11W46] was quiet and stable.
Region 11875 [N06W22] lost spots and decayed slightly. There is still a significant magnetic delta structure in the trailing spot section. A major flare is possible. C5+ flares: C9.3/1F at 05:58, M2.5/1F at 10:09, M3.5 at 10:33 UTC.
Region 11877 [S12W03] was mostly unchanged and still has a number of spots around the northern half of the large penumbra. Further major flares are possible. C5+ flares: major M9.3/1N at 00:28 (associated with a faint halo CME), C5.7 at 22:10 UTC.
Region 11879 [S12E12] developed slowly and quietly.
New region 11881 [S22E37] emerged on October 22 and was numbered by SWPC 2 days later.
New region 11882 [S09E78] rotated partly into view on October 23 and has large trailing penumbra. The region produced an M2.9 flare at 03:02 UTC on October 25.
Spotted regions not numbered by SWPC:
S2753 [N18W71] developed slowly and quietly.
S2769 [N18W22] was quiet and stable.
S2774 [S17W58] was quiet and stable.
S2776 [N15E15] was quiet and stable.
New region S2780 [S10E46] emerged with a penumbra spot.
A large filament eruption was observed in the northeast quadrant early on October 25.
Minor update posted at 16:15 UTC: AR 11882 has produced 2 X class flares today. The first was an impulsive X1.7 event at 08:01 and was associated with a relatively small CME off the east limb. Then at 15:03 an impulsive X2.1 flare peaked. The region has a magnetic delta structure in the trailing penumbra and is likely to produce further major flares as long as that structure persists.
October 22: A partial CME was observed early in the day following a
filament eruption in the northeast quadrant. A small halo CME was associated with the M4 event in AR 11875 late in the day.
October 23: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
October 24: A faint halo CME was observed after the M9 event in AR 11877 early in the day.
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. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet to active on October 25 due to CME effects. On October 26 unsettled to minor storm conditions are possible due to effects from the CME observed early on Oct.24.
|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
|Total spot count:||88||175||94|
|Sunspot number:||148||295||184||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||123||218||137||(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):||89||103||101||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||125.4 (1)||91.3 (2A) / 118.0 (2B) / 68.1 (2C)||(53.9 projected, -1.5)||(8.65)|
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.