Relationships between Tropical Cyclones and Madden–Julian Oscillation-Associated Extratropical Circulation Patterns

As a fundamental part of the global circulation, the Madden–Julian oscillation (MJO) influences the evolution of large-scale circulation patterns proximate to and far from its convective envelope. Tropical cyclones (TCs) also modulate large-scale circulation patterns across the globe, especially following their recurvature and interaction with mid- and high-latitude circulations. Consequently, TCs that occur in conjunction with active MJO events often modify extratropical circulation outcomes associated with the MJO and possibly contribute to particular patterns of forecast error.

Composites based on MJO phase without regard for TC track or location, and different combinations of MJO phase and TC track type (i.e., recurving and non-recurving), will be presented and compared. Composite patterns will help to elucidate the relative extent to which TCs contribute to or interfere with large-scale extratropical circulation patterns associated with the MJO. Results will be extended to GFS reforecast data to identify systematic model errors associated with the MJO, TCs, and combinations thereof. Statistical methods developed to improve associated model performance will then be discussed.