Last update issued on May 17, 2003 at 03:30 UTC.
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The geomagnetic field was quiet to unsettled on May 16. Solar wind speed ranged between 504 and 656 km/sec, the high speed stream from coronal hole CH38 ended early in the day.
Solar flux measured at 20h UTC on 2.8 GHz was 102.6. The planetary A
index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 10.5).
Three hour interval K indices: 32222233 (planetary), 32222322 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight there were 5 spotted regions on the visible disk. Solar flare activity was very low.
Region 10356 decayed further. If the region continues to decay at the current rate, no spots will be visible by
tomorrow.
Region 10357 developed slowly and quietly.
Region 10358 decayed and lost all spots outside of the main penumbra.
Region 10361 decayed and could soon become spotless.
Region 10362 was mostly unchanged and quiet.
May 14-16: No obviously geoeffective CMEs observed.
Coronal hole history (since late October 2002)
Compare today's report with the situation one solar rotation ago: 28
days ago 27 days ago 26
days ago
A recurrent trans equatorial coronal hole (CH39) was in a geoeffective position on May 15-16. A recurrent trans equatorial coronal hole (CH40) will rotate into a geoeffective position on May 18-20.
Processed SOHO EIT 284 image at 19:06 UTC on May 16. Any black areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on May 17. A high speed stream from coronal hole CH39 will likely reach Earth on May 18 and cause unsettled to active geomagnetic conditions that day and on May 19. A high speed stream from coronal hole CH40 is expected to influence the field May 21-24. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very poor and will likely be very poor until at least May 25. Propagation along north-south paths is fair to good and is likely to be at least fair until May 25. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay.]
Coronal holes (1) | Coronal mass ejections (2) | M and X class flares (3) |
1) Effects from a coronal hole could reach Earth within the next 5 days.
2) Material from a CME is likely to impact 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.
Compare to the previous day's image.
Data for all numbered solar regions according to the Solar Region Summary provided by SEC/NOAA. 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 SEC or where SEC has observed no spots.
Solar region | Date numbered | SEC spot count |
STAR spot count |
Location at midnight | Area | Classification | Comment |
---|---|---|---|---|---|---|---|
10356 | 2003.05.09 | 10 | 2 | N18W29 | 0030 | CSO | |
10357 | 2003.05.11 | 4 | 6 | S17E07 | 0050 | DAO | |
10358 | 2003.05.12 | 3 | 1 | N08W30 | 0030 | CSO |
classification was HSX at midnight |
10359 | 2003.05.12 | 2 | S14W75 | 0020 | AXX | spotless | |
10360 | 2003.05.14 | S05W47 | plage | ||||
10361 | 2003.05.15 | 7 | 2 | N08E25 | 0030 | HSX |
classification was AXX at midnight, area 0010 |
10362 | 2003.05.15 | 11 | 13 | S11E64 | 0240 | DAO |
area was 0130 at midnight |
S158 | emerged on 2003.05.14 |
S10W72 | now spotless | ||||
Total spot count: | 37 | 24 | |||||
SSN: | 97 | 74 |
Month | Average solar flux at Earth |
International sunspot number | Smoothed sunspot number |
---|---|---|---|
2000.04 | 184.2 | 125.5 | 120.8 cycle 23 sunspot max. |
2000.07 | 202.3 | 170.1 | 119.8 |
2001.12 | 235.1 | 132.2 | 114.6 (-0.9) |
2002.04 | 189.8 | 120.7 | 110.5 (-2.9) |
2002.05 | 178.4 | 120.8 | 108.8 (-1.7) |
2002.06 | 148.7 | 88.3 | 106.2 (-2.6) |
2002.07 | 173.5 | 99.6 | 102.7 (-3.5) |
2002.08 | 183.6 | 116.4 | 98.7 (-4.0) |
2002.09 | 175.8 | 109.6 | 94.6 (-4.1) |
2002.10 | 167.0 | 97.5 | 90.5 (-4.1) |
2002.11 | 168.7 | 95.5 | (84.9 predicted, -5.6) |
2002.12 | 157.2 | 80.8 | (80.5 predicted, -4.4) |
2003.01 | 144.0 | 79.5 | (77.5 predicted, -3.0) |
2003.02 | 124.5 | 46.2 | (72.4 predicted, -5.1) |
2003.03 | 131.4 | 61.5 | (66.8 predicted, -5.6) |
2003.04 | 126.4 | 60.0 | (61.9 predicted, -4.9) |
2003.05 | 113.3 (1) | 50.0 (2) | (57.9 predicted, -4.0) |
1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
2) Unofficial, accumulated value based on the Boulder (SEC/NOAA) sunspot number. The official international sunspot number is typically 25-45% less.
This report has been prepared by Jan Alvestad. It is based partly on my own observations and interpretations, and partly on data from sources noted in solar links. All time references are to the UTC day. Comments and suggestions are always welcome.
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