THE RELATIONSHIP BETWEEN EMEX MESOSCALE PRECIPITATION FEATURE PROPERTIES AND THEIR ENVIRONMENTAL CHARACTERISTICS

Characteristics of the prestorm environment of Equatorial Mesoscale Ex periment (EMEX) mesoscale precipitation features (MPFs) are related to properties of these systems using regression analysis. Although envir onmental thermodynamic parameters are poorly correlated with EMEX MPF properties (mainly because environmental thermodynamic conditions vari ed little among MPFs), kinematic parameters are well correlated to the se properties. Lines whose environments have low-level shear (the shea r between about 950 and 750 mb) exceeding 5 m s-1 are oriented normal to the direction of this shear; lines where the low-level shear is und er 5 m s-1 are oriented along the direction of the midlevel shear (the shear between about 800 and 400 mb). Convective line speeds correlate well with the maximum speed of the rear-to-front flow in the troposph ere below 300 mb. Direction of MPF motion is nearly coincident with th e tropospheric mean wind direction. Peak convective line length is pro portional to the magnitude of the mean along-line wind in the cloud la yer. The lower-tropospheric drying that a system causes is proportiona l to the shear within two different layers-800-400 and 1000-800 mb.