Last major update issued on April 4, 2014 at 05:20 UTC.
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[Presentation
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SSN Workshop, Tucson, 2013 (pdf)]
The geomagnetic field was quiet on April 3. Solar wind speed at SOHO ranged between 349 and 454 km/s.
Solar flux at 20h UTC on 2.8 GHz was 153.0 (increasing 4.8 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 155.1. The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 5.6). Three hour interval K indices: 12122112 (planetary), 12132322 (Boulder).
The background x-ray flux is at the class B5 level.
At the time of counting spots (see image time), spots were observed in 15 active regions in 2K resolution (SN: 333) and 13 active regions in 1K resolution (SN: 226) SDO images on the visible solar disk.
Region 12021 [S13W28] changed as the large spots
split into several penumbrae. C and M flares are still possible.
Region 12022 [N17W15] was quiet and stable.
Region 12024 [N17W44] was quiet and stable.
Region 12026 [S11E27] has a large trailing spot as
several spots merged into one penumbral structure. C and M class flares are possible.
Region 12027 [N12E31] was quiet and stable.
Region 12028 [S08E37] gained a few penumbra spots.
Region 12029 [N17E15] matured and was quiet.
Region 12030 [N11E43] has polarity intermixing and remains capable of at
least C class flaring.
C5+ flare: C5.5 at 04:14 UTC.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3277 [S27W26] reemerged with penumbra spots.
S3288 [N04E18] developed slowly and quietly.
S3295 [S11W04] was quiet and stable.
S3297 [N08W28] developed umbra on both polarities.
New region S3298 [N08E34] emerged with penumbra spots.
New region S3299 [N13W05] emerged with a few spots.
New region S3300 [S13E73] rotated into view with a penumbra spot.
April 1: A filament eruption from approx. 14:30 to 17h UTC in just east
of the central meridian mostly in the southeast quadrant and extending into the
northeast quadrant was the likely source of a full halo CME observed a little
later in LASCO imagery.
April 2: A large and fast asymmetrical full halo CME was observed after
the M6.5 event in AR 12027. The CME could reach Earth on April 4.
April 3: No obviously Earth directed CMEs were observed in LASCO and
STEREO imagery.
Coronal hole history (since October
2002)
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 potentially geoeffective positions.
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 active on April 4-5 due to CME effects and quiet on April 6.
| 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
green.
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) 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 detected |
Spot count | Location at midnight | Area | Classification | SDO / HMI 4K continuum image with magnetic polarity overlay |
Comment | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| SWPC | Magnetic (SDO) |
SWPC | STAR | Current | Previous | ||||||
| 2K | 1K | ||||||||||
| 12020 | 2014.03.24 2014.03.27 |
S13W67 | |||||||||
| S3264 | 2014.03.26 | N08W52 | plage | ||||||||
| S3267 | 2014.03.26 | S22W46 | plage | ||||||||
| 12022 | 2014.03.27 2014.03.28 |
1 | 9 | 4 | N18W17 | 0010 | HRX | CRO |
 |
images/AR_12022_20140402_2345.png |
area: 0035 location: N17W15 |
| 12025 | 2014.03.27 2014.03.30 |
S24W75 |
plage location: S20W69 |
||||||||
| 12021 | 2014.03.28 | 14 | 40 | 21 | S13W30 | 0320 | DKI | DAC |
 |
 |
area: 0510 location: S13W28 |
| 12024 | 2014.03.28 2014.03.29 |
1 | N17W51 | 0002 | AXX |
 |
 |
location: N17W44 | |||
| S3276 | 2014.03.28 | S12W36 | plage | ||||||||
| S3277 | 2014.03.28 | 2 | 1 | S27W26 | 0006 | AXX |
 |
||||
| S3278 | 2014.03.28 | S17W58 | plage | ||||||||
| S3280 | 2014.03.28 | N09W52 | plage | ||||||||
| 12026 | 2014.03.30 | 30 | 50 | 31 | S11E25 | 0230 | EAC | DKC |
 |
 |
location: S11E27 area: 0570 |
| 12027 | 2014.03.30 2014.03.31 |
4 | 9 | 5 | N13E29 | 0110 | CAO | CAO |
 |
 |
area: 0230 location: N12E31 |
| S3288 | 2014.03.31 | 5 | 3 | N04E18 | 0020 | CRO |
 |
 |
|||
| 12028 | 2014.03.31 2014.04.01 |
2 | 11 | 6 | S08E37 | 0020 | CRO | DRO |
 |
 |
|
| S3290 | 2014.03.31 | S20E03 | plage | ||||||||
| 12029 | 2014.04.01 | 8 | 20 | 9 | N17E16 | 0060 | DAO | DAO |
 |
 |
area: 0120 |
| 12030 | 2014.04.01 | 8 | 21 | 8 | N11E43 | 0050 | DAO | DAI |
 |
 |
area: 0130 |
| S3294 | 2014.04.01 | S05W56 | plage | ||||||||
| S3295 | 2014.04.02 | 2 | 1 | S11W04 | 0007 | BXO |
 |
 |
|||
| S3296 | 2014.04.02 | S01W02 |
 |
plage | |||||||
| S3297 | 2014.04.02 | 5 | 3 | N08W28 | 0035 | DRO |
 |
 |
|||
| S3298 | 2014.04.03 | 4 | 2 | N08E34 | 0013 | BXO |
 |
||||
| S3299 | 2014.04.03 | 3 | 2 | N13W05 | 0017 | CRO |
 |
||||
| S3300 | 2014.04.03 | 1 | S13E73 | 0002 | AXX |
 |
|||||
| Total spot count: | 67 | 183 | 96 | ||||||||
| Sunspot number: | 137 | 333 | 226 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 103 | 228 | 142 | (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): | 82 | 117 | 124 | 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 (WDC-SILSO) |
Smoothed sunspot number | Average ap (3) |
|
|---|---|---|---|---|---|
| Measured | 1 AU | ||||
| 2013.01 | 127.1 | 123.1 | 62.9 | 58.7 (-0.9) | 4.69 |
| 2013.02 | 104.3 | 101.8 | 38.0 | 58.4 (-0.3) | 6.11 |
| 2013.03 | 111.3 | 110.2 | 57.9 | 57.5 (-0.9) | 10.56 |
| 2013.04 | 124.8 | 125.9 | 72.4 | 57.9 (+0.4) | 5.40 |
| 2013.05 | 131.4 | 134.3 | 78.7 | 59.9 (+2.0) | 9.73 |
| 2013.06 | 110.1 | 113.7 | 52.5 | 62.6 (+2.7) | 12.60 |
| 2013.07 | 115.5 | 119.3 | 57.0 | 65.5 (+2.9) | 9.47 |
| 2013.08 | 114.6 | 118.3 | 66.0 | 69.0 (+3.5) | 8.27 |
| 2013.09 | 102.6 | 103.7 | 36.9 | 73.1 (+4.1) | 5.23 |
| 2013.10 | 132.1 | 131.2 | 85.6 | (74.9 projected, +1.8) | 7.71 |
| 2013.11 | 148.3 | 145.1 | 77.6 | (74.9 projected, -0.0) | 5.68 |
| 2013.12 | 147.7 | 143.1 | 90.3 | (74.4 projected, -0.5) | 4.68 |
| 2014.01 | 157.4 | 152.4 | 82.0 | (74.3 projected, -0.1) | 5.44 |
| 2014.02 | 170.3 (cycle peak) |
166.3 | 102.8 (cycle peak) | (73.7 projected, -0.6) | 10.70 |
| 2014.03 | 149.9 | 148.5 | 92.2 | (73.8 projected, +0.1) | 4.88 |
| 2014.04 | 153.7 (1) | 12.9 (2A) / 129 (2B) / 108.6 (2C) | (73.0 projected, -0.8) | (5.1) | |
1) Running average based on the daily 20:00 UTC observed solar flux value at
2800 MHz.
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.
