The Impact of Western Pacific Tropical Cyclones on North Pacific Jet Circulations

The interaction between a tropical cyclone (TC) and a midlatitude jet-front system can result in substantial changes to the structure of the extratropical tropopause and the midlatitude Rossby waveguide. As TC outflow encroaches upon an extratopical jet-front system, a region of diabatically reduced PV and static stability is introduced into the vicinity of that jet-front system. Previous work focused on nontropical convection proximate to a jet-front system has shown that the reduction in static stability resulting from the diabatically generated convective outflow is associated with a robust response from the dynamically forced frontal circulations in the vicinity of the extratropical tropopause. These robust vertical circulations are associated with tilting frontogenesis above the jet core along the lower stratospheric front. In addition, the vertical circulations provide a mechanism to tilt the tropopause into a more upright orientation that subsequently alters the structure of the extratropical jet-front system. This presentation will expand upon previous work by addressing the interactions of the convectively generated TC outflow with the dynamically driven vertical circulations in an extratropical jet-front system. The present work focuses on Western Pacific TCs from the 2001-2010 period and the impacts of TC outflow on the North Pacific jet. The analysis highlights several representative cases that illustrate the subsynoptic scale TC-jet interaction, as well as the downstream high impact weather consequences of the TC-altered jet.