Frontal System across Europe with Wave Development - Case Study 12 - 13 November 1997

• I. Synoptic Situation for 12 November 06.00 UTC
• Overview and frontal diagnosis
• Wave development in the area Sardinia - Corsica
• Intensification of frontal cloudiness and activity by jet streak crossing
• Cloudiness over Italy and the Balkan peninsula in front of the Cold Front: Relative Streams
• II. Development During the next 12 Hours
• Frontal displacement with help of the Thermal Front Parameter
• Displacement of the Wave
• Front Intensification by Jet Crossing
• III. Synoptic Situation for 12 November 12.00 UTC
• Overview and new aspects
• Diagnosis of front and Wave(s)
• Relative streams: Cloudiness over the Balkan peninsula
• IV. Synoptic Situation for 12 November 18.00 UTC
• Comparison of cloud configurations between 12.00 and 18.00 UTC
• Overall situation and frontal diagnosis
• Relative streams
• V. Synoptic Situation for 13 November 00.00 UTC
• Introduction for 13 November 00.00 UTC
• Overview and frontal situation
• Relative streams: Frontal and pre-frontal situation
• VI. Development of Thunderstorms and MCSs During the Whole Period
• Introduction for the diagnosis of conceptual modles for convective developments
• The period 12 November 05.00 - 07.00 UTC
• The period 12 November 11.00 - 12.00 UTC
• The period 12 November 14.00 - 18.30 UTC
• The period 12 November 21.00 UTC - 13 November 00.00 UTC
• Some summarizing ideas

Introduction for the diagnosis of conceptual modles for convective developments

There will be two different approaches for the diagnosis of conceptual models for convective developments:

The small scale approach

The diagnosis of convective developments with help of observations; the following material will be used:

• Satellite imagery: cold cloud top enhancement
• Weather reports
• Lightning reports
• Development images indicating new development and decay of cloudiness

In the satellite imagery typical configurations like cellular structures, circular and oval shapes and differences between IR and VIS are used for diagnosis. Development images will be used to try to get some information about life cycle and further development.

The meso - to synoptic scale approach

The description and use of conceptual models of the synoptic environment of the convective developments; the following material and tools are used:

• Overview in satellite imagery
• Stability index on isobaric surfaces: Showalter index
• Numerical model parameters on isobaric surfaces
• Numerical model parameters in vertical cross section; special attention is paid to:
  • Vertical distribution of TA
  • Vertical distribution of convergence
  • Vertical distribution of PVA
• Relative streams for discrimination of different air masses
• PV (optionally)

The overview in the satellite imagery is also used to sort out configurations with cold cloud tops which are connected with non-convective conceptual models like, for instance, high Lee Cloud.