Intraseasonal Forecasting of the Madden-Julian Oscillation and Tropical Cyclone 05

Intraseasonal forecasting of the Madden-Julian Oscillation (MJO) and Tropical Cyclone 05 (TC05) that occurred during the DYNAMO period from November to December 2011 is conducted using the Navy's non-hydrostatic COAMPS regional modeling system in a two-way coupled mode. Lateral boundary conditions are provided by NOGAPS (Navy Operational Global Atmospheric Prediction System) analyses. The model domain covers the tropics and subtropics and extends from the eastern Atlantic to the eastern Pacific with 45-km and 27-km horizontal resolutions. Initiation and propagation of the MJO and TC05 and interactions between these two systems from 60-day forecasts are verified using observed outgoing longwave radiation (OLR), TRMM precipitation estimates, and NOGAPS analyses. The results from 27-km provide a better representation of the three MJO events that occurred during this 2-month period. Significant error in the development of TC05 in the 45-km forecast is due to weak vertical wind shear expanded over an excessive area. Examination of two eastward propagating Kelvin waves that influence the initiation of the MJO and interact with TC05 from the 45-km and 27-km forecasts indicates higher horizontal resolution is necessary to improve intraseasonal forecasting for the MJO and TC05.