Understanding the Impact of Radar and In Situ Observations on the Prediction of a Nocturnal Convection Initiation Event on 25 June 2013 Using an Ensemble-Based Multiscale Data Assimilation System

• DOI: 10.1175/mwr-d-17-0128.1
• Publication Date: 2018-05-08T20:10:24Z
• Authors: Samuel K. Degelia; Xuguang Wang; David J. Stensrud; Aaron Johnson
• Keywords: Mesoscale convective system; Nowcasting

The initiation of new convection at night in the Great Plains contributes to a nocturnal maximum precipitation and produces localized heavy rainfall severe weather hazards region. Although previous work has evaluated numerical model forecasts data assimilation (DA) impacts for (CI), most studies focused only on that initiates during afternoon not explicitly thunderstorms. In this study, we investigate impact assimilating situ radar observations CI event 25 June 2013 using an ensemble-based DA forecast system. Results study show successful resulted when conventional inner, convection-allowing domain. Assimilating strengthened preexisting southwestern Kansas by enhancing buoyancy locally strengthening low-level convergence. enhanced produced cold pool that, together with increased convergence along northwestern jet (LLJ) terminus near region CI, was important mechanism lifting parcels their level free convection. Gravity waves were also atop provided further elevated ascent. improved suppressing spurious reducing number ensemble members outflow boundary. fact assimilated suggests accurately capturing preconvective environment specific mesoscale features is especially forecasts.