Study of Two Upper Cold Lows and Their Relationship with Locally Intense Rain

Abstract

The main objective of the research was to determine the synoptic and mesoscale conditions, which, under the influence of two Upper Cold Lows (UCL), favor the occurrence of locally intense rain in Cuba. From the outputs of the Rapid Refresh (RAP) model, the characteristics of two UCL with four cases of locally intense rain associated with them were analyzed. The variables that were studied are relative humidity, temperature, geopotential height, vertical speed, wind force, divergence and vorticity. Mesoscale conditions were analyzed by using the Weather Research and Forecast System (WRF) model. Vertical cuts, numerical soundings and analysis of radar observations and satellite images were carried out. The CAPE shows extreme values higher than 6000 J/kg near the center of both systems and the LI reaches −13. The cases were developed in an environment of weak vertical wind shear in the surface layer −500 hPa and moderate to strong in the upper troposphere. High relative humidity values were identified at low levels, a dry layer was identified at medium levels and an increase in relative humidity was identified in the 300–200 hPa layer.