Last major update issued on February 18, 2014 at 04:50 UTC.
[Solar and geomagnetic data - last month (updated
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update February 1, 2014)] [Cycle 24 progress (last update February 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update February 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update February 1, 2014)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update February 1, 2014)]
[POES auroral activity level since October
2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated February 1, 2014]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]
The geomagnetic field was quiet on February 17. Solar wind speed at SOHO ranged between 355 and 429 km/s.
Solar flux at 20h UTC on 2.8 GHz was 152.4 (increasing 6.4 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 149.3. The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.9). Three hour interval K indices: 11000112 (planetary), 11111212 (Boulder).
The background x-ray flux is at the class C1 level.
At the time of counting spots (see image time) spots were observed in 13 active regions in 2K resolution (SN: 264) and 10 active regions in 1K resolution (SN: 171) SDO images on the visible solar disk.
Region 11974 [S11W86] was quiet and stable. SWPC is counting AR S3098 and
this group as one.
Region 11976 [S15W42] was quiet and stable.
Region 11977 [S10W17] decayed slowly and has minor polarity intermixing. C5+ flare: C6.6/1F at 03:04 UTC. A small CME was observed in STEREO imagery after this event.
Region 11980 [S13W32] decayed slowly and quietly.
New region 11981 [S06E59] emerged on February 6 and was numbered by SWPC the next day.
New region 11982 [S11E70] rotated into view on February 6 and got its NOAA number the next day. The region is compact and could produce M class flares.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3098 [S11W76] decayed slowly and produced a few low level C flares. An M class flare is still possible.
S3127 [S23E03] was quiet and stable.
S3129 [S12E55] developed slowly and quietly.
New region S3132 [N10W70] emerged with a few spots.
New region S3134 [S17E60] emerged with a penumbra spot.
New region S3135 [S31E28] emerged with penumbra spots.
New region S3136 [S23W29] emerged with penumbra spots.
New region S3137 [S21E40] emerged with a penumbra spot.
A filament eruption in the southeast quadrant began late in the day. At least a partial halo CME was associated with this event (too early at the time of writing to tell if this is a full halo CME).
February 15-16: No obviously Earth directed CMEs were observed in LASCO and
February 17: A small CME was observed in STEREO imagery after a C6 event in AR 11977 near center disk. The CME could reach Earth on February 20.
February 18: A large CME was observed after a filament eruption in the southeast quadrant. The CME could reach Earth on February 20 or 21.
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
An extension (CH603) of a northern hemisphere coronal hole may have been marginally in a geoeffective position on February 14. In that case a weak disturbance could reach Earth on February 18. A trans equatorial coronal hole (CH604) could rotate into an Earth facing position on February 20-21.
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 poor.
The geomagnetic field is expected to be quiet to unsettled on February 18 and quiet on February 19. On February 20 a weak CME culd reach Earth early in the day and cause a few unsettled intervals. A stronger CME impact is likely later in the day or early on February 21 which could cause unsettled to minor storm conditions.
|Coronal holes (1)||Coronal mass ejection (2)||M and X class flares (3)|
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
SWPC has this as part of AR 11974
|Total spot count:||41||134||71|
|Sunspot number:||101||264||171||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||76||185||122||(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):||61||92||94||k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for STAR SDO 2K, k = 0.55 for STAR SDO 1K|
|Month||Average solar flux||International sunspot number
|Smoothed sunspot number||Average ap
|2011.11||153.5||96.7 (cycle peak)||61.1 (+1.2)||5.55|
|2013.08||114.6||118.3||66.0||(69.0 projected, +3.5)||8.27|
|2013.09||102.6||103.7||36.9||(73.0 projected, +4.0)||5.23|
|2013.10||132.1||131.2||85.6||(74.0 projected, +1.0)||7.71|
|2013.11||148.3||145.1||77.6||(72.9 projected, -1.1)||5.68|
|2013.12||147.7||143.1||90.3||(71.8 projected, -1.1)||4.68|
|152.4||82.0||(71.0 projected, -0.8)||5.44|
|2014.02||173.0 (1)||104.0 (2A) / 171.2 (2B) / 108.7 (2C)||(71.2 projected, +0.2)||(7.5)|
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 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.