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 - Introduction For Very Short Range Forecast

02 August 1997/06.00 UTC - Meteosat IR image; yellow: thermal front parameter (TFP) 500/850 hPa 06.00 UTC, green: thermal front parameter (TFP) 500/850 hPa 12.00 UTC, blue: thermal front parameter (TFP) 500/850 hPa 18.00 UTC	02 August 1997/06.00 UTC - Meteosat IR image; yellow: temperature advection - WA 1000 hPa 06.00 UTC, green: temperature advection - WA 1000 hPa 12.00 UTC, blue: temperature advection - WA 1000 hPa 18.00 UTC
02 August 1997/06.00 UTC - Meteosat IR image; yellow: positive vorticity advection (PVA) 300 hPa 06.00 UTC, green: positive vorticity advection (PVA) 300 hPa 12.00 UTC, blue: positive vorticity advection (PVA) 300 hPa 18.00 UTC	02 August 1997/06.00 UTC - Meteosat IR image; yellow: height contours 1000 hPa 06.00 UTC, green: height contours 1000 hPa 12.00 UTC, blue: height contours 1000 hPa 18.00 UTC

The images show the displacement of the key parameters TFP (left image top), WA (right image top), PVA at 300 hPa (left image bottom), surface (right image bottom) and finally upper level height (image below).

03 August 1997/06.00 UTC - Meteosat IR image; yellow: height contours 500 hPa 06.00 UTC, green: height contours 500 hPa 12.00 UTC, blue: height contours 500 hPa 18.00 UTC

Some of the key parameters clearly support the development of Rapid Cyclogenesis, such as the TFP which for the first time during this case study develops an Occlusion - like configuration extending from Cornwall to south-east Ireland for 18.00 UTC. Also the WA maximum intensifies markedly by 18 UTC over Cornwall and Ireland. On the other hand the surface low retains its strength without any intensification during its eastward movement, as does the PVA maximum. As can be seen, the upper level low moves slowly south-south-eastwards, while its vertical axis becomes more perpendicular.

Summarizing, from the diagnosis of the 06.00 UTC situation and the VSRF of all relevant key parameters, many clues can be found for the occurence of Rapid Cyclogenesis. This will be verified by the sequence of images.