Want to better understand weather patterns? This study presents a physical discussion of vorticity and its change by stretching and tilting, leading to the conservation of quasi-geostrophic potential vorticity (PV). Using maps of PV on isentropic surfaces and potential temperature on PV surfaces, the authors illustrate synoptic developments in the North Atlantic-Europe regions. Examples include a summer situation and a major blocking event in January 1996, thus promoting the role of potential vorticity in forecasting weather. The discussion naturally leads on to the conservation of quasi‐geostrophic potential vorticity, q, and the flow associated with anomalies in q. The extension to full potential vorticity (PV) and the associated conservation and inversion properties is made. The use for illustrating and understanding synoptic developments of maps of PV on isentropic surfaces and potential temperature (θ) on PV surfaces is shown by considering two recent examples in the North Atlantic–Europe regions. This work highlights the value of PV diagnostics in illustrating and understanding synoptic developments, with concluding remarks on the role of diabatic processes and other possible uses of these diagnostics.
This paper, published in Meteorological Applications, is well-suited for the journal's focus on practical applications of meteorological science. By presenting a physical discussion of potential vorticity and illustrating its use in understanding synoptic developments, the research offers insights that can be directly applied in weather forecasting and climate analysis, aligning with the journal's aim of promoting the use of meteorological knowledge in real-world scenarios.