The Extratropical Transition of Tropical Storm Banyan
Abstract
During July 2005, Typhoon Banyan recurved and underwent extratropical transition over the western North Pacific. Coincident with the extratropical transition of Banyan, a large mid-tropospheric anticyclone developed immediately east of the recurving typhoon. The anticyclone was associated with a high-amplitude, Rossby wave-like pattern that developed downstream of the anticyclone and extended across the North Pacific. Development of the anticyclone is examined with respect to the interaction between the outflow from Banyan and the midlatitude jet streak. During the poleward movement of TY Banyan, an anticyclonically-curved jet streak was forced by the merger of the upper-level outflow from Banyan and a jet streak associated with an upstream trough. The anticyclonic curvature was accentuated by the presence of a mid-tropospheric cyclone east of Banyan. The anticyclonic curvature increased as Banyan moved poleward and the mid-tropospheric cyclone moved equatorward. Thermodynamic forcing of the mid-tropospheric anticyclone is examined with respect to the poleward movement of warm moist air that ascends as it is advected around the eastern side of the decaying typhoon. The combination of dynamic and thermodynamic factors is examined in a potential vorticity framework to identify the development of the anticyclone east of Banyan and the transformation of Banyan into a midlatitude cyclone.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2006
- Accession Number
- ADA457251
Entities
People
- Michael D. Vancas
Organizations
- Naval Postgraduate School