Impact of initial SST fields on Hurricane Edouard (2014) forecasts with the HWRF model

Sea surface temperatures (SST) can directly affect the evolution and structure of tropical

cyclones (TCs) by modulating enthalpy fluxes at the air-sea interface, thus affecting TC intensity

forecasts. The Atlantic warm pool, defined by SST exceeding 28.5ºC, is known to have

significant impact on the North Atlantic hurricane activity. In 2014, Hurricane Edouard passed

over a warm pool and experienced rapid intensification and an eyewall replacement cycle while

entering and exiting this pool. This case study investigates the influence of initial SST fields on

Hurricane Edouard (2014) forecasts using the Hurricane Weather and Research Forecasting

(HWRF) model with the inner most grid resolution at ~ 2 km. Experiments employ SST fields

that provide different locations and strength of the warm pool. In addition to using the

Generalized Digital Environmental Model (GDEM) climatology, Navy Coupled Ocean Data

Assimilation (NCODA) analysis products for the month of September each year from 2010-2014

are used as initial conditions to drive the forecasts of Hurricane Edouard. Sensitivity of

Hurricane Edouard intensity prediction, wind and thermal structure, evolution, and specifically

the eyewall replacement cycle to different SST fields is examined and discussed.