Last major update issued on March 13, 2014 at 04:30 UTC.
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The geomagnetic field was quiet to unsettled on March 12. Solar wind speed at SOHO ranged between 275 and 317 km/s. A disturbance began slowly late in the day, possibly due to effects from CH607. Active conditions have been observed early on March 13.
Solar flux at 20h UTC on 2.8 GHz was 147.6 (decreasing 19.0 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 153.9. The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.0). Three hour interval K indices: 32221123 (planetary), 20111212 (Boulder).
The background x-ray flux is at the class B7 level.
At the time of counting spots (see image time) spots were observed in 11 active regions in 2K resolution (SN: 240) and 10 active regions in 1K resolution (SN: 171) SDO images on the visible solar disk.
Region 11996 [N14W80] was the most active region on
the visible disk. There is a magnetic delta structure in the central section and
further M class flares are possible on March 13-14 while the region is at or
just behind the northwest limb.
C5+ flares: C7.2 at 07:57, M2.5 at 11:05, C5.3 at
17:40, major M9.3 at 22:34 UTC.
Region 11998 [S09W25] decayed losing all umbra.
Region 12000 [S11W33] decayed and lost the leader spot.
Region 12002 [S19E10] decayed slowly and was mostly quiet. The region has a magnetic delta structure and could produce an M class flare.
Region 12003 [N06W37] developed further and was mostly quiet.
Region 12004 [S08E37] decayed slowly and quietly.
New region 12005 [N12E71] rotated into view on March 11 and was numbered the next day by SWPC.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3210 [S18W73] was quiet and stable.
New region S3211 [S09W48] emerged just ahead of AR 12000.
New region S3212 [N17W26] emerged with penumbra spots.
New region S3213 [N20E07] emerged with a penumbra spot.
An active region 4-5 days behind the northeast limb produced a large flare at 14:16 UTC, this event was associated with a halo CME.
March 10-12: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
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
A small southern hemisphere coronal hole (CH607) was in an Earth facing position on March 9.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is fair.
The geomagnetic field is expected to be quiet to active on March 13, likely due to effects from CH607. Quiet conditions are likely on March 14-15.
|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
real location: S14W70
SWPC has adopted the spots of AR S3210
|Total spot count:||75||130||71|
|Sunspot number:||145||240||171||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||105||163||104||(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):||87||84||94||k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for MSN 2K, k = 0.55 for MSN 1K (MSN=Magnetic Sunspot Number)|
|Month||Average solar flux||International sunspot number
|Smoothed sunspot number||Average ap
|2013.09||102.6||103.7||36.9||(72.8 projected, +3.8)||5.23|
|2013.10||132.1||131.2||85.6||(73.8 projected, +1.0)||7.71|
|2013.11||148.3||145.1||77.6||(72.7 projected, -1.1)||5.68|
|2013.12||147.7||143.1||90.3||(71.6 projected, -1.1)||4.68|
|2014.01||157.4||152.4||82.0||(71.6 projected, 0.0)||5.44|
|166.3||102.8 (cycle peak)||(70.9 projected, -0.7)||10.70|
|2014.03||153.5 (1)||59.5 (2A) / 153.8 (2B) / 119.4 (2C)||(71.0 projected, +0.1)||(4.2)|
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 WDC-SILSO 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 GFZ 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.