Solar Terrestrial Activity Report

Last major update issued on June 16, 2005 at 03:55 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update June 4, 2005)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update June 4, 2005)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update June 4, 2005)]
[Historical solar and geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports (last update June 4, 2005)]

Recent activity

The geomagnetic field was quiet to minor storm on June 15. Solar wind speed ranged between 448 and 532 km/sec, slowly decreasing after 14h UTC.

Solar flux measured at 20h UTC on 2.8 GHz was 94.5. The planetary A index was 21 (STAR Ap - based on the mean of three hour interval ap indices: 21.4).
Three hour interval K indices: 35334332 (planetary), 34344332 (Boulder).

The background x-ray flux is at the class B1 level.

At midnight there were 4 spotted regions on the visible solar disk. The solar flare activity level was low. A total of 1 C class event was recorded during the day.

Region 10775 was quiet and stable and will rotate over the northwest limb today.
Region 10776 was mostly unchanged.  Flare: C2.2 at 18:43 UTC.
New region 10778 emerged in the northwest quadrant on June 14 and was numbered the next day by SEC.
New region 10779 emerged in the southeast quadrant on June 14 and was noticed by SEC the next day. The region developed quickly and could produce C flares.

Coronal mass ejections (CMEs)

June 14: A full halo CME was observed in LASCO images after a long duration C4 event in region 10775 during the morning. With no available LASCO images covering the C7 long duration event later in the day, it is uncertain if there was another full halo CME then.
June 13 and 15: No obvious fully or partly Earth directed CMEs were observed in LASCO images.

Coronal holes

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

An elongated coronal hole (CH170) in the northern hemisphere was in an Earth facing position on June 11-13.

Processed SOHO/EIT 284 image at 01:06 UTC on June 6. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to minor storm on June 16 due to a high speed stream from CH170. The CME observed on June 14 could arrive during the latter half of June 16 or early on June 17 and cause unsettled to major storm conditions. Quiet to active is likely on June 18 becoming quiet to unsettled on June 19.

Coronal holes (1) Coronal mass ejections (2) M and X class flares (3)
Coronal hole indicator CME indicator M and X class flare indicator

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.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is very poor. Propagation along long distance north-south paths is poor to fair. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay. Rádio Metropolitana on 930 and Rádio Eldorado on 700 kHz both had impressive signals,  weak signals from other stations from Brazil were observed on several other frequencies,

Active solar regions (Recent map)

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
spot
count
STAR
spot
count
Location at midnight Area Classification Comment
10775 2005.06.04 4 1 N09W74 0230 DHO classification was HAX at midnight, area 0180
10776 2005.06.05 5 1 S05W64 0320 CHO classification was HHX at midnight
10777 2005.06.10     N05W11     plage
10778 2005.06.15 1 3 N07W38 0030 HSX formerly region S558
10779 2005.06.15 14 12 S17E08 0150 DAI formerly region S559
S556 2005.06.09     N05W73     plage
Total spot count: 24 17  
SSN: 64 57  

Monthly solar cycle data

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)
2004.04 101.2 39.3 45.5 (-1.6)
2004.05 99.8 41.5 43.8 (-1.7)
2004.06 97.4 43.2 41.6 (-2.2)
2004.07 119.1 51.1 40.2 (-1.4)
2004.08 109.6 40.9 39.2 (-1.0)
2004.09 103.1 27.7 37.5 (-1.7)
2004.10 105.9 48.0 35.9 (-1.6)
2004.11 113.2 43.5 35.3 (-0.6)
2004.12 94.5 17.9 (34.8 predicted, -0.5)
2005.01 102.2 31.3 (32.8 predicted, -2.0)
2005.02 97.2 29.1 (30.4 predicted, -2.4)
2005.03 89.9 24.8 (28.8 predicted, -1.6)
2005.04 86.0 24.4 (26.9 predicted, -1.9)
2005.05 99.3 42.6 (24.3 predicted, -2.6)
2005.06 102.6 (1) 40.2 (2) (22.8 predicted, -1.5)

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% lower.

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.


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