The Effects of Western Pacific Basin Tropical Cyclones on the Extratropical Circulation Associated with the MJO and its Propagation

Both the Madden Julian oscillation (MJO) and tropical cyclones are associated with substantial signals in the extratropical atmospheric circulation. Since the MJO influences the formation and movement of TCs, part of the extratropical signal associated with composite MJO events might include circulation outcomes associated with TCs. Also, although clearly not a necessary condition for MJO formation, tropical cyclones that form in association with different phases of the MJO in different geographical locations might also influence its propagation and development or breakdown. This presentation with show the first preliminary results in an ongoing project that investigates the association between the MJO and extratropical circulation outcomes when TCs are located in particular geographical regions or are absent, with special emphasis on TCs in the Northwest Pacific basin during Northern Hemisphere fall. The presentation will also show the potential influence of tropical cyclones on the organization of convection associated with the MJO. Composite analysis of the global atmospheric circulation patterns associated with TCs will show how TCs embedded within the MJO are associated with different preferred circulation outcomes. Circulation patterns associated with TCs in these regions will then be analyzed during selected MJO states.