Publication Date

Fall 2022

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Meteorology and Climate Science

Advisor

Sen Chiao

Subject Areas

Meteorology, Climate change

Abstract

This study evaluates the relationship between tropical cyclone (TC) genesis, also known as tropical cyclogenesis, and precipitation in forecasts produced by the Basin-scale Hurricane Weather Research and Forecasting (HWRF-B) model. Pre-TC (PTC) forecasts from HWRF-B were produced during the 2017-2020 hurricane seasons in the North Atlantic and eastern North Pacific. In PTC forecasts, various precipitation characteristics, including rate, and coverage, were compared for different forecast outcomes of signal detection: hits, misses, false alarms, and correct rejections. Moreover, differences in radar reflectivity, mid-tropospheric moisture, and vertical wind shear (VWS) were studied and compared for developing (i.e., underwent cyclogenesis) and non-developing PTCs. In particular, we focused on comparisons between hits and false alarms (i.e., developing PTC forecasts), as well as between misses and correct negatives (i.e., non-developing PTC forecasts), to distinguish one forecast outcome from the other. In other words, the goal is to determine if developing and non-developing PTC forecasts are accurate based on precipitation, moisture, and wind shear. The result from this study indicates that the developing cases had greater maximum precipitation rates as well as a larger area coverage of higher precipitation rates at most lead/lag times. Further, VWS results revealed that non-developing disturbances also experienced weak upper-level flow. Together, these results indicate that thermodynamic properties play an important role in determining the evolution of disturbances in the North Atlantic basin.

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