Last major update issued on May 5, 2005 at 05:10 UTC.
geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update April 4, 2005)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update April 4, 2005)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update April 4, 2005)]
[Historical solar and geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports (last update May 2, 2005)]
The geomagnetic field was quiet to unsettled on May 4. Solar wind speed ranged between 342 and 454 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 108.7. The planetary
index was 7 (STAR Ap - based on the mean of three hour interval ap
Three hour interval K indices: 33111221 (planetary), 33102121 (Boulder).
The background x-ray flux is at the class B4 level.
At midnight there were 2 spotted regions on the visible solar disk. The solar flare activity level was low. A total of 2 C class events was recorded during the day.
Region 10756 decayed slowly losing spots and penumbral area.
Region 10758 developed many new spots and has a rather messy magnetic field layout. An M class flare could cause an ejection of a large filament running through the region. Flares: C1.1 at 14:15 and C1.2 at 22:46 UTC.
May 2: A full halo CME was observed in LASCO C3 images beginning at 06:18 UTC. There was no significant activity on the
visible disk during the hours just before this observation and the origin of the CME was likely backsided, possibly with the same
origin as the CMEs observed on April 30 and May 1. A large and bright CME was observed over most of the eastern limb late in the
day and early on May 3.
May 3: A partial halo CME was observed in LASCO C3 images beginning at 19:42 UTC. The source of this CME was likely backsided.
May 4: No obviously fully or partly potentially geoeffective CMEs were observed.
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 large recurrent coronal hole (CH163) in the northern hemisphere will likely rotate to an Earth facing position on May 6-7.
Processed SOHO/EIT 284 image at 01:06 UTC on May 5. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected be quiet to unsettled on May 5-8 becoming unsettled to major storm on May 9-10 due to a high speed stream from CH163.
|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. When the high speed stream has arrived
the color changes to green.
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.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor. Propagation along long distance north-south paths is poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay with CPN Radio (Perú) becoming dominant during the hour before local sunrise. On other frequencies only a few stations were noted, most of them from Argentina and Perú.
Compare to the previous day's image.
Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SEC. 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. SEC active region numbers in the table below and in the active region map above are the historic SEC/USAF numbers.
|Active region||Date numbered||SEC
|Location at midnight||Area||Classification||Comment|
|10756||2005.04.25||12||14||S07W52||0760||DKC||area was 0500 at midnight|
|10757||2005.04.28||1||S05W79||0030||HSX||spotless at midnight|
|Total spot count:||31||43|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2004.11||113.2||43.5||(34.8 predicted, -1.1)|
|2004.12||94.5||17.9||(33.4 predicted, -1.4)|
|2005.01||102.2||31.3||(30.9 predicted, -2.5)|
|2005.02||97.2||29.1||(28.3 predicted, -2.6)|
|2005.03||89.9||24.8||(26.5 predicted, -1.8)|
|2005.04||86.0||24.4||(24.6 predicted, -1.9)|
|2005.05||111.2 (1)||8.3 (2)||(22.0 predicted, -2.6)|
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 (NOAA/SEC) sunspot number. The official international sunspot number is typically 30-50% less.
This report has been prepared by Jan Alvestad. It is based partly on my own observations and analysis, and partly on data from some of these solar data sources. All time references are to the UTC day. Comments and suggestions are always welcome.