by KNMI and DHMZ
04 August 2005/18.00 UTC - Meteosat 8 IR10.8 image
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04 August 2005/18.00 UTC - synop observations in the area of interest
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Environment favourable for development of convection, equivalent thickness ridge
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04 August 2005/18.00 UTC - ECMWF model analysis field; green: equivalent thickness
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Environment favourable for development of convection, Potential Temperature (ThetaW) at 850 hPa
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04 August 2005/18.00 UTC - ECMWF model analysis field; cyan: equipotential temperature 850 hPa
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Environment favourable for development of convection, Low Level Divergence
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04 August 2005/18.00 UTC - ECMWF model analysis field; magenta: Divergence 925 hPa
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Environment favourable for development of convection, Boyden Index
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04 August 2005/18.00 UTC - ECMWF model analysis field; orange: Boyden Index
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09 July 2006/12.00 UTC - Meteosat 8 HRVIS image
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09 July 2006/12.00 UTC - Radio sounding Zagreb
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09 July 2006/12.00 UTC - Radar Image
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09 July 2006/12.00 UTC - Meteosat 8 IR10.8 image with nowcasting product Convective Cell Detection
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Furthermore, radar images are essential in diagnosing the strength of a Cb Clusters in terms of precipitation amount and dangerous weather events like wind gusts, heavy hail or downbursts (see "Radar" in Cumulonimbus (Cb) and Mesoscale Convective System (MCS) - Key Parameters ).
On the bases of radar and satellite images more and more nowcasting tools are developed. Nowcasting algorithm used in this investigations (Convective Cells Detection in the image above) detects convective cells on the basis of their top temperature and radius, with three temperature thresholds where blue cross indicates the cell with cloud top temperature lower than -33°C, yellow lower than -42°C and red lower than -50°C.
The height of the cloud top is a good indication of the potential activity of the cell. Besides radar derived data, cloud top temperatures can be retrieved from IR images. The estimated top height is computed using the IR temperature and the temperature height profile derived from the nearest available radio sounding. In the diagram shown below, the average cloud top height in the early studies for this manual is 275 hPa (with dispersion about 100 hPa) lying just below the mean value of the tropopause height.