A composite perspective of the extratropical flow response to recurving western North Pacific tropical cyclones

AMS Citation:
Archambault, H. M., D. Keyser, L. F. Bosart, C. A. Davis, and J. M. Cordeira, 2015: A composite perspective of the extratropical flow response to recurving western North Pacific tropical cyclones. Monthly Weather Review, 143, 1122-1141, doi:10.1175/MWR-D-14-00270.1.
Date:2015-04-01
Resource Type:article
Title:A composite perspective of the extratropical flow response to recurving western North Pacific tropical cyclones
Abstract: This study investigates the composite extratropical flow response to recurving western North Pacific tropical cyclones (WNP TCs), and the dependence of this response on the strength of the TC-extratropical flow interaction as defined by the negative potential vorticity advection (PV) by the irrotational wind associated with the TC. The 2.5° NCEP–NCAR reanalysis is used to construct composite analyses of all 1979-2009 recurving WNP TCs and of subsets that undergo strong and weak TC-extratropical flow interactions. Findings indicate that recurving WNP TCs are associated with the amplification of a preexisting Rossby wave train (RWT) that disperses downstream and modifies the large-scale flow pattern over North America. This RWT affects approximately 240° of longitude and persists for approximately 10 days. Recurving TCs associated with strong TC-extratropical flow interactions are associated with a stronger extratropical flow response than those associated with weak TC–extratropical flow interactions. Compared with weak interactions, strong interactions feature a more distinct upstream trough, stronger and broader divergent outflow associated with stronger midlevel frontogenesis and forcing for ascent over and northeast of the TC, and stronger upper-level PV frontogenesis that promotes more pronounced jet streak intensification. During strong interactions, divergent outflow helps anchor and amplify a downstream ridge, thereby amplifying a preexisting RWT from Asia that disperses downstream to North America. In contrast, during weak interactions, divergent outflow weakly amplifies a downstream ridge, such that a RWT briefly amplifies in situ before dissipating over the western-central North Pacific.
Peer Review:Refereed
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OpenSky citable URL: ark:/85065/d74j0g88
Publisher's Version: 10.1175/MWR-D-14-00270.1
Author(s):
  • Heather Archambault
  • Daniel Keyser
  • Lance Bosart
  • Christopher Davis - NCAR/UCAR
  • Jason Cordeira
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