|Charts (* = updated daily||Data and archive|
|Solar wind (*)||Solar and geomagnetic data - last month (*)|
|Electron fluence (*)||Archived daily reports and monthly data from 2003.01 (May 1, 2016)|
|Solar cycle||Solar cycles 23-24 (May 1, 2016)||Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)|
|Cycle 24 progress (May 1, 2016)||Noon SDO sunspot count 1K / 4K (*)|
|Solar cycles 1-24 (July 17, 2015)||POES auroral activity level October 2009 - December 2012|
|Comparison of cycles 21, 22, 23 and 24 (May 1, 2016)||3rd SSN Workshop, Tucson, 2013|
|Comparison of cycles 12, 13, 14, 16 and 24 (May 1, 2016)||4th SSN Workshop, Locarno, 2014|
|Solar polar fields vs. solar cycles (May 20, 2016)|
The geomagnetic field was quiet to active on May 21 under the influence of effects from CH735. Solar wind speed at SOHO ranged between 445 and 512 km/s.
Solar flux at 20h UTC on 2.8 GHz was 97.8 (increasing 16.0 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 92.8. The Potsdam WDC planetary A index was 14 (STAR Ap - based on the mean of three hour interval ap indices: 13.6). Three hour interval K indices: 23423321 (planetary), 33533221 (Boulder).
The background x-ray flux is at the class B1 level.
At the time of counting spots (see image time), spots were observed in 3 active regions using 2K resolution (SN: 57) and 2 active regions using 1K resolution (SN: 31) SDO images on the visible solar disk.
Region 12546 [S07W21] produced B class events, none of them significant. The region was mostly unchanged.
Spotted regions not numbered (or interpreted differently) by SWPC:
New region S5289 [S30W12] emerged with a tiny spot.
New region S5290 [N15E30] was observed with tiny spots in an old plage area.
|Magnitude||Peak time (UT)||Location||AR||Recorded by||Comment|
May 19-21: No obviously Earth directed CMEs were observed in available LASCO imagery.
history (since October 2002)]
[Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago]
A decaying coronal hole (CH735) was in an Earth facing position on May 16-18. A recurrent coronal hole (CH736) in the southern hemisphere will likely rotated across the central meridian on May 22-24. A recurrent northern hemisphere coronal hole (CH737) will likely rotate into a potentially geoeffective position on May 25.
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 May 22 due to effects from CH735 and quiet to unsettled on May 23 becoming quiet on May 24.
|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: 0-30% probability, Yellow: 30-70% probability, Red: 70-100% probability.
(Click on image for 2K resolution). 4K resolution. Compare to the previous day's image. 0.5K image
|Active region||Date numbered
|Spot count||Location at midnight||Area||Classification||SDO / HMI 4K continuum
image with magnetic polarity overlays
|Total spot count:||7||27||11|
|Sunspot number:||17||57||31||(total spot count + 10 * number of spotted regions)|
|Relative sunspot number (Wolf number):||19||31||25||k * (sunspot number)
As of May 7, 2016: k = 1.1 for SWPC, k = 0.55 for MSN 2K, k = 0.80 for MSN 1K (MSN=Magnetic Sunspot Number)
|Month||Average solar flux||International sunspot number
|Smoothed sunspot number (4)||Average
|166.3||146.1 (cycle peak)||110.5 (+1.2)||10.70|
|2014.04||143.9||144.8||112.5||116.4 (+2.1) (solar max)||7.88|
|2015.11||109.3||106.9||63.2||(61.2 projected, -3.2)||12.09|
|2015.12||113.1||109.5||57.7||(58.8 projected, -2.4)||14.29|
|2016.01||103.4||100.1||56.6||(57.1 projected, -1.7)||9.4|
|2016.02||103.6||101.0||57.2||(54.8 projected, -2.3)||9.9|
|2016.03||91.5||90.6||54.9||(51.9 projected, -2.9)||10.58|
|2016.04||93.3||94.0||38.0||(49.1 projected, -2.8)||9.03|
|2016.05||(94.1)||39.8 (2A) / 58.8 (2B) / 61.5 (2C)||(47.2 projected, -1.9)||(12.8)|
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).
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.
4) Updated to new data set from WDC-SILSO on July 1, 2015
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 Universal Time. Comments and suggestions are always welcome.
SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.