Abstract A study of several configurations of numerical forecast models was conducted to evaluate their skill to forecast tropical cyclones track and intensity. For this, four configurations of the horizontal domain were selected with 27-9 and 18-6 km of resolution for HWRF (Hurricane Weather Research and Forecasting Model) and four configurations for the WRF (Weather Research and Forecasting Model), using the dynamic core NMM (Non-hydrostatic Mesoscale Model) with the vortex tracker option. Simulations corresponding to Hurricane Irma were done from 1st to 12th September 2017, initialized with GFS (Global Forecast System) forecast outputs. No notable differences were observed between the eight configurations, although the forecast of the intensity of Hurricane Irma was deficient, with an error in the forecast of the maximum wind speed above 50 km/h. The comparison of the outputs of each configuration with buoys and surface meteorological stations data showed that the behavior of the wind speed and atmospheric pressure variables has a similar tendency to the registered values in the stations, with errors lower than 3.8 m/s for wind speed and 3 hPa for atmospheric pressure. HWRF 18-6-m (referred to the model and the horizontal domain resolution) was the configuration that showed the best ability for tropical cyclones forecast, although it require large time to compute.

Resumen Se realizó un estudio de caso de varias configuraciones de modelos de pronóstico numérico para evaluar la habilidad de los mismos en el pronóstico de la intensidad y trayectoria de los ciclones tropicales. Para ello se seleccionaron 4 configuraciones del dominio de cómputo con 27-9 y 18-6 km de resolución para el HWRF (Hurricane Weather Research and Forecasting Model) y 4 configuraciones para el WRF (Weather Research and Forecasting Model), empleando el núcleo dinámico NMM (Non-hydrostatic Mesoscale Model) con la opción de seguimiento de vórtice. Se realizaron las simulaciones correspondientes al huracán Irma desde el 1ro al 12 de septiembre del 2017 inicializadas con salidas de pronóstico del GFS (Global Forecast System). En la evaluación realizada no se observaron diferencias notables entre las 8 configuraciones, aunque fue deficiente el pronóstico de la intensidad del huracán Irma, con un error en el pronóstico de la velocidad máxima del viento superior a los 50 km/h. La comparación de las salidas de cada configuración con los registros de las boyas y estaciones meteorológicas de superficie evidenció que el comportamiento de las variables viento y presión atmosférica tiene una tendencia similar a los valores registrados en las estaciones, con errores inferiores a los 3.8 m/s para la velocidad del viento y 3 hPa para la presión atmosférica. La configuración que mostró mejor habilidad para el pronóstico de ciclones tropicales fue HWRF_18-6-m (referida al modelo y la resolución horizontal empleada), aunque es la que más capacidad de cómputo requiere.

ABSTRACT The feasibility of an operational near-real-time forecasting system to simulate the ocean-atmosphere behaviour for the Inter-American Seas and Cuba is presented. The modelling system includes the combination of the WRF atmospheric model, the Wavewatch III and SWAN wave models and the ROMS hydrodynamic model. The main atmospheric and oceanic variables are predicted twice per day for up to 72 hours. WRF initial and boundary conditions are supplied by the GFS global atmospheric model outputs with a resolution of 1/2 degree. Ocean boundary conditions are derived from the HYCOM global ocean model outputs with 1/12 degrees of spatial resolution and the tidal data used is obtained from the Oregon State University global model of oceanic tides TPXO7. Results from WRF were used as atmospheric forcing to run the wave and ocean models. To validate the forecast results, real-time monitoring data from NDBC (National Data Buoy Center) and Cuban weather stations for 2013 were used. Results show a reasonably good performance of the system developed. This operational modelling system was originally developed for the National Meteorological Service but it also provides forecasts for public services.

A study of the oceanic surface layer is presented, taking into account its vertical thermal structure and time-space variability. Oceanographic data from 37 cruises were used. The thickness of the isothermal layer and depth of the 26°C isotherm were determined. The possible connection between the thermal characteristics of the sea surface layer and tropical cyclone activity was analyzed. The presence of ENSO was considered. We show that the thermal characteristics of Cuban waters are always favorable for tropical cyclone development.

Se presenta un estudio de la estructura térmica vertical y la variabilidad espaciotemporal de la capa superficial oceánica en aguas cubanas, utilizando datos de 37 expediciones oceanográficas realizadas de 1966 a 1993. Se determinaron el espesor de la capa isotérmica y la profundidad de la isoterma de 26°C. Se analizó el posible enlace entre las características térmicas de la capa superficial oceánica y el comportamiento de los ciclones tropicales. Se tuvo en cuenta la presencia de la Oscilación del Sur El Niño (ENOS). Se concluye que las características térmicas de las aguas cubanas siempre son favorables al desarrollo de los ciclones tropicales, independientemente de la presencia de ENOS.