Advancements in the Prediction of Littoral Quasi-linear Mesoscale Convective Systems

Funds are provided to conduct research to advance our knowledge and improve the prediction of littoral quasi-linear Mesoscale Convective Systems (MCS), a globally ubiquitous and destructive atmospheric phenomenon. Quasi-linear MCSs impact coastal and offshore regions with heavy rains, flash flooding (which can contribute to mud slides), frequent lightning, high winds, hail, tornadoes (waterspouts), and meteotsunamis, and can severely damage coastal and offshore Naval assets and operations. Improved forecasts of littoral quasi-linear MCSs require a more complete understanding of the combined role the MABL and coastal topography on storm lifecycle, severity, and the governing physical processes. The PI will use cloud resolving numerical simulations to quantify the influence of littoral terrain and MABL on the environmental conditions important to quasi-linear MCSs (instability, vertical wind shear), and the subsequent impacts on storm characteristics (ascent mechanism type and structure, contribution of buoyant versus dynamic ascent, propagation speed), evolution (probability of coastal crossing), and severity (convective and stratiform precipitation structure, severe wind potential). Numerical sensitivity experiments will be conducted exploring a phase space of topographic (terrain height, slope; escarpment, island) and MABL (depth, thermal perturbation) characteristics. Anticipated benefits include a deeper understanding of the physical processes important to littoral MCS evolution and severity, the identification of topographic-MABL regimes most influential on MCS lifecycle, and improved forecasts of the destructive phenomenon.