Case Study: 29 July 1997

• Introduction and Conceptual Models for 29 July 1997/06.00 UTC
  • Overview of satellite features and conceptual models
  • Frontal diagnosis
  • Diagnosis of the western cloud feature - Conceptual model "Front Intensification by Jet Crossing"
  • Diagnosis of the eastern cloud feature - Conceptual models "Convergence Cloudiness" and "Cumulonimbus (Cb) and Mesoscale Convective System (MCS)"
  • Diagnosis for 06.00 UTC with help of vertical cross sections
  • Very Short Range Forecast (VSRF) till 18.00 UTC
• Conceptual Models - Diagnosis for 29 July 1997/12.00 UTC
  • Satellite features and frontal diagnosis for 12.00 UTC
  • The western cloud system
  • The eastern cloud system
  • Instability 12.00 UTC
  • Diagnosis for 12.00 UTC with help of vertical cross sections
• Conceptual Models - Diagnosis for 29 July 1997/18.00 UTC
  • Satellite features and frontal diagnosis for 18.00 UTC
  • Upper level features
  • Instability 18.00 UTC
  • Diagnosis for 18.00 UTC with help of vertical cross sections
  • Summary

29 July 1997 - Summary

This case study shows a non-frontal situation where a distinct upper level feature, namely an upper level trough and jet streak producing PVA and cloudiness, crosses a completely different feature of a convergence band with some instability embedded. This mergence leads to a highly unstable troposphere and the development of intensive thunderstorms.

The model was very well able to diagnose and forecast the situation as a whole. But as expected, it was not able to forecast the location of single thunderstorm developments. For this purpose only methods used for nowcasting are appropriate tools at the present time.