Case Study: 02 - 03 August 1997

• I. Introduction and SatRep Diagnosis for 02 August 1997/06.00 UTC
  • Introduction
  • Overview of satellite imagery for 02 August 06.00 UTC
  • Key parameters on isobaric surfaces for 02 August 06.00 UTC
  • Relative streams and conveyor belts for 02 August 06.00 UTC
• II. Development of Upper Level Low and Rapid Cyclogenesis
  • Introduction for Upper Level Low and Rapid Cyclogenesis
  • Very Short Range Forecast from 02 August 06.00 UTC - 18.00 UTC
  • Development of cloud configurations during Very Short Range Forecast
• III. Diagnosis for 03 August 1997/00.00 UTC
  • Overview of satellite imagery for 03 August 00.00 UTC
  • Key parameters on isobaric surfaces for 03 August 00.00 UTC
  • Relative streams and conveyor belts for 03 August 00.00 UTC
  • Summary
• IV. Diagnosis for 03 August 1997/06.00 UTC
  • Overview of satellite imagery for 03 August 06.00 UTC
  • Key parameters on isobaric surfaces for 03 August 06.00 UTC
• V. Very Short Range Forecast from 03 August 1997/06.00 UTC - 18.00 UTC
  • Introduction for Very Short Range Forecast
  • Development of cloud configurations during Very Short Range Forecast for 03 August 06.00 UTC - 18.00 UTC
  • Diagnosis for 03 August 18.00 UTC with parameters on isentropic surfaces

02 - 03 August 1997 - Overview Of Satellite Imagery For 03 August 06.00 UTC

03 August 1997/06.00 UTC - Meteosat IR image; SatRep overlay: names of conceptual models	03 August 1997/06.00 UTC - Meteosat WV image
03 August 1997/06.00 UTC - Meteosat VIS image	03 August 1997/06.00 UTC - Meteosat IR image; red: height contours 1000 hPa, green: height contours 500 hPa

The images show the cloud configurations in the three Meteosat channels. Although the Upper Level Low (ULL) is now indicated in the SatRep (superimposed on the IR image), clear indications of an Upper Level Low cannot be extracted from the IR image alone (left image top). Only WV and VIS structures together with the numerical model key parameters (right image bottom) contribute to this diagnosis. In the VIS image (left image bottom) a circulation centre with two cyclonically curved cloud bands can be identified around 53N/25W; this is the region where also a circulation centre can be noticed within the WV band (right image top).

The intensive dry Black Stripe in the WV is now clearly to the south of the Upper Level Low spiral structure just mentioned; it moved to south Ireland and is connected with the intensified cloud area east of Ireland and a newly developed cellular cloud area over Ireland. This is a new aspect during this case study which could be recognised only now: the encouplement of the spiral feature of the Upper Level Low and the Dark Stripe at the rear of the frontal cloud bands might be an additional factor for an imminent Rapid Cyclogenesis.