Last major update issued on February 19, 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 to unsettled on February 18. Solar wind speed at SOHO ranged between 336 and 420 km/s. A weak disturbance arrived near 06:30 UTC and caused unsettled conditions during the latter half of the day and a minor storm interval early on February 19. Based on ACE data the origin of this disturbance was likely a CME. A moderate solar wind shock was observed at ACE near 03:05 UTC on February 19, the CME could cause major geomagnetic storming as the interplanetary magnetic field has is strongly southwards.
Solar flux at 20h UTC on 2.8 GHz was 151.4 (increasing 8.1 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 149.3. The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 7.6). Three hour interval K indices: 20211233 (planetary), 10112332 (Boulder).
The background x-ray flux is at the class B8 level.
At the time of counting spots (see image time) spots were observed in 11 active regions in 2K resolution (SN: 256) and 10 active regions in 1K resolution (SN: 178) SDO images on the visible solar disk.
Region 11976 [S14W56] gained a few spots and was
Region 11977 [S10W29] decayed slowly and was mostly quiet.
Region 11980 [S15W45] decayed further and could soon become spotless.
Region 11981 [S07E48] developed and could produce C flares.
Region 11982 [S11E59] developed and has M class flare potential. There is polarity intermixing and numerous dasrk surges on the disk were observed.
New region 11983 [S13E40] emerged on February 16 and was numbered by SWPC 2 days later.
New region 11984 [S16E47] emerged on February 17 and received its NOAA number the next day.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3098 [S11W85] rotated partly out of view and was mostly quiet.
S3135 [S31E15] edecayed slowly and quietly.
New region S3138 [S13E11] emerged with a penumbra spot.
New region S3139 [N07W33] emerged during the latter half of the day with several spots.
A filament eruption in the northeast quadrant was observed beginning at 22:13 UTC. STEREO-A displays a small CME with no data yet in LASCO imagery.
February 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: An asymmetric full halo 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
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 very poor. Propagation on long distance northeast-southwest paths is poor to fair.
The geomagnetic field is expected to be quiet to major storm on February 19-21 due to CME effects. A high speed stream from CH604 could cause unsettled and active intervals on February 23-24.
|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
actual location: S11W99
rotated out of view
SWPC has this as part of AR 11974
|Total spot count:||54||146||78|
|Sunspot number:||134||256||178||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||102||192||124||(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):||80||90||98||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||171.8 (1)||108.8 (2A) / 169.2 (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 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.